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>> [MUSIC PLAYING]

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ALLISON BUCHHOLTZ-AU: All right,
everyone, welcome back to section.

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Hopefully you all had a great
Halloween weekend, or Halloweekend,

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as I like to say, all
rested and recovered.

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And thankfully it's not snowing anymore.

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It's actually sunny outside.

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I was real happy about that.

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Not ready to drag out my winter boots.

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Hopefully, pset6 went pretty well.

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>> If you are tired of C, I'm happy
to say you're done with C for now.

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We have fully transitioned
into web programming,

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so you'll be working in HTML, PHP,
maybe a little bit of JavaScript.

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I don't know what next week's
pset is, so I can't guarantee

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what your next pset will
be, but this week's pset

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is CS50 Finance, which is basically
implementing the sort of web page

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that allows you to buy and sell
stock, and keep track of them.

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And it's pretty cool, because all
of it is dynamically generated.

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You can have different users who
each have their own information,

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and you're going to be
implementing all of that.

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It takes a while.

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I definitely think this is easier
than C psets, but it takes longer.

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You're learning a new language,
PHP, which is very similar to C,

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but of course is going to require
you to look up syntax and understand

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how to convert between the languages.

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>> But I don't think there's anything
super conceptually hard about this pset.

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It's just learning the
new language and getting

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through all these little pieces.

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If you guys have read through
the spec, it's pretty long.

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I think this one is like 21
pages, if I remember correctly.

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It's a long spec.

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So if you haven't read it-- 22.

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32.

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>> Wow.

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So I was off by 50% there.

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So, 32 pages.

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So it's long.

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There are lots of pieces, but none
of the pieces should be that bad.

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It's just a lot.

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So definitely get started early
if possible, as per usual,

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but I think it should feel a little
nicer than especially the psets like

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recover and resize that are just
very hard to wrap your head around.

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>> So with that, we're going to dive in.

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I don't have your agenda
slide today, but we're

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going to be talking about PHP.

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I'll be giving you kind of a
crash course on some things

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that you might want to know about PHP.

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Different syntax things,
things to look out for.

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We're going to be talking
a little bit about SQL.

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Just very simple things
there, and then also MVC

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is Model View Controller, which
is how your pset is set up,

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so understanding how that
works will be super useful.

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All right.

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So PHP.

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You guys should have done
something very, very simple

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with PHP, which is
this bottom thing here,

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where you submitted some form on the
top here that had some name that you

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input, and it would say like hello, Ben,
or hello, Allison, and it would pop up.

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So this is actually what it
should've looked like from your pset,

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in case you guys wanted to know
or didn't quite figure it out.

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>> But we have these question marks
here that indicate that this is PHP.

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They wrap it, and then
htmlspecialcharge, remember, is just,

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make sure that you're safe
from any crazy injection attack

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or if someone tries to put
crazy malicious characters

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into your name field, it doesn't
like up your server or whatnot.

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>> And then if we notice, this HTML
form had a method of $_GET, which,

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if we remember our superglobals
from PHP, $_GET, $_POST,

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we'll be going into
those in a little bit.

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But we know that we have some name
here that corresponds to the name

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that we submitted.

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So this is just kind of like the
very simple PHP HTML collaboration

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that you guys had from pset six.

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>> But that doesn't really
answer what is PHP.

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Obviously it's a language,
but we haven't really

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talked about it in this section,
so there's a little bit more

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about what PHP actually is.

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So PHP is just PHP
hypertext preprocessor.

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>> It's actually considered
a programming language

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because it has logic, whereas if
we remember talking about HTML,

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we called that a markup language versus
a programming language because HTML

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is strictly modifying how
things look on the page.

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It's just modifying
whether something's bold,

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or whether it's a form,
element, or something like that.

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It doesn't have any logic.

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It doesn't have loops or conditions.

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You can't error check things.

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You would either display things
in a certain way or ask for things

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from the user.

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That's it.

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>> So with PHP, it actually does allow us
to do all of these more logical things,

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like validate the input or
manipulate it in some way.

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We can combine it with HTML, as we just
saw in your last pset and right now,

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and it allows us to create
these dynamic web pages.

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So if you guys ever-- I don't know if
you were like me, but in middle school

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they had us take this IT class where
we created just HTML web pages,

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and they were static and click around
to other things, but they never changed.

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>> With dynamic ones, what we can
do is, like with CS50 Finance,

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you're going to have different users.

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Depending on those users'
preferences, and what they're buying

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or what they're selling
for their stocks,

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you're going to display
different things.

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So if there's some
identifying characteristic

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for your user using this
web page, we can dynamically

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decide what to display for them.

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It's not the same thing for every single
person, which if we just had HTML,

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the page would be the same for
every single person who visited.

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PHP allows us to personalize pages.

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>> And then we can either put them in
the same file, which, as in the case

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before here, we saw that
we have HTML all here

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and then we have this little bit of PHP.

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We can do like that,
or with CS50 Finance,

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if you guys have looked at the
files-- and we should have time

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to step through a couple of them
together at the end of the section-- we

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can see how you can
actually keep them separate,

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which is actually a better thing to do.

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>> So.

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Crash course.

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All the quick simple things
you might need to know for PHP.

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Declaring variables.

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That blue's a little annoying,
but hopefully you guys can see it.

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If not, I'll write it
on the chalk board.

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The declaring variables.

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One thing to know is that, unlike C,
PHP is loosely or dynamically typed,

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which means that you don't need to
tell a variable what type it is.

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You can just simply say some variable
is equal to whatever you want it to,

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and it will decide the type of
that variable at run time for you.

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>> As you'll see, this can create
some very interesting things.

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But for most purposes, you
don't need to specify the type.

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You can, and you can type
cast things like you normally

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wouldn't see if you want to
force it to be a certain type,

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but you don't have to.

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It's not going to yell at you
if you just declare a variable

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and don't specify a type for it.

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>> So in case you can't read
this-- I know it's not the best.

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I thought it would show up better-- the
way you initialize any variable is just

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with a dollar sign, what
you want it to be called,

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and then what you're assigning it.

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So in this case, this is some $var = 3.

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So if we ever use $var
somewhere, it will just

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be the same as putting 3 there.

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OK?

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>> So, any variable, just
dollar sign, whatever

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you want to call your variable,
and whatever you want it to equal.

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Little cooler.

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Less to write for initializing
a variable, right?

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Does that make sense to everyone?

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Just quick syntax difference
between C and PHP.

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>> Arrays are much cooler in PHP.

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We can give them keys.

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So the way to think about
it is that, if we ever

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wanted to access an
element within an array,

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we needed to know the
index of it, right?

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So we know that with C, we
could access the first element

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by doing array bracket zero, or if we
want the first element, array bracket

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one.

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And if we wanted something
in there, we might just

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have to iterate through, unless
we actually knew the index.

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>> One thing that is really
cool with PHP arrays

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is that they're what
we call associative.

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So we can associate
some key to some value,

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and we're actually going
to-- I will show you

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how we can use this in a second.

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But basically, if you ever want
to initialize an array like that,

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you have some $array.

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>> So in the same way, it's just
some variable that we're creating.

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This could be called
whatever you wanted.

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This could be $example.

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Just another variable.

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What makes it an array is the
bracket syntax that we have here.

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Just like normal C. And we
have some key to some value.

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So key1 goes to value1,
key2 two goes to value2.

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These pairs are separated with a
comma, just like normal arrays.

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>> However.

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Big one.

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Keys are optional.

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You don't have to use them.

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And if you don't, then it's just normal.

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Question?

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Or, oh.

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>> AUDIENCE: Well, about the right.

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Where's the memory coming from?

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Can it also be the same like
[INAUDIBLE] and from the stack?

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Is that also using PHP?

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Like when we're linking them?

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>> ALLISON BUCHHOLTZ-AU:
With PHP, We don't tend

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to worry about where our
memory's coming from.

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We don't spend a lot of
time talking about that,

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so it's not really anything
you need to worry about.

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So keys are optional.

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In the same way, if you don't
want to make this associated,

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you just want a normal array where
array zero is the first element

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and array one is the second
element, you can do it exactly

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as you would in C. You have some
variable that's going to be your array,

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and it equals these brackets here.

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Yes.

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>> AUDIENCE: Does it have the
same point to notation.

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Like, I can do like a array++,
and that points to the second one.

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>> ALLISON BUCHHOLTZ-AU: You can do--
Well, you can have some iterator, i,

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that you can do i++ and do a
array of i in the same way.

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But that's it.

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So, like in this case,
array of 1 would equal 20.

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Same sort of indexing notation.

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This is basically just an implicit thing
here, where it says zero, zero to 10,

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to 1 to 20, 2 to 30.

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It's just implicit keys for it.

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What changes with PHP is
that you now have the power

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to reassign those keys to
do whatever you'd like.

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>> So one thing is here.

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So I have just some examples
here that I wrote up for you guys

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because I feel like examples always
help more than just the abstract.

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So, in this case here, we
have some associative array

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that is my first name,
my last name, and I

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am echoing, which is just
for all purposes here

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going to print out to the output here.

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>> And it says, OK.

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Print out the value that
corresponds to array at key Allison.

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And I can also send you guys
all this code after class.

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So, when we run this, what do
you think is going to happen?

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What's going to print out?

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AUDIENCE: Your last name.

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ALLISON BUCHHOLTZ-AU: My last name.

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It does.

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Right here.

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Print out.

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So if we were to change this and we
were to add someone else to our list--

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So let's say we have Emma here,
and we associate your last name--

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Let's see if I spell this right.

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>> AUDIENCE: Yeah.

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>> ALLISON BUCHHOLTZ-AU: Yes.

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>> AUDIENCE: Good job.

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>> ALLISON BUCHHOLTZ-AU: Lovely.

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So now if we have this here and
we wanted to find your last name,

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you have it there.

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So you can just think of it
as replacing this key here.

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You're just replacing the index.

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So it allows you to just search
through an array much easier.

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You don't need to know the index.

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As long as this key that you're looking
for exists somewhere in the array,

239
00:12:43,470 --> 00:12:47,660
PHP will find it and it will return
the value associated with it.

240
00:12:47,660 --> 00:12:49,840
So it gives you a lot more
power with your arrays.

241
00:12:49,840 --> 00:12:50,340
Yes.

242
00:12:50,340 --> 00:12:53,131
>> AUDIENCE: If you have two keys the
same, will it give you an error?

243
00:12:53,131 --> 00:12:55,830
ALLISON BUCHHOLTZ-AU: It
should give you an error, yeah.

244
00:12:55,830 --> 00:12:58,520
Does that make a little
more sense for you guys?

245
00:12:58,520 --> 00:13:07,640
And in the same way, we have an array
here that doesn't have any keys.

246
00:13:07,640 --> 00:13:10,910
Also this is a syntax
that you might want

247
00:13:10,910 --> 00:13:13,550
to be aware of, because you'll
have to use this in your pset.

248
00:13:13,550 --> 00:13:17,317
>> Whenever you're doing an
echo, you have these quotes,

249
00:13:17,317 --> 00:13:19,400
and whenever you're referring
to part of an array,

250
00:13:19,400 --> 00:13:22,180
you have to have these
curly braces around them.

251
00:13:22,180 --> 00:13:25,630
It's kind of annoying, but
you just have to do it.

252
00:13:25,630 --> 00:13:28,010
So just something to keep in mind.

253
00:13:28,010 --> 00:13:31,490
If you're running into errors of,
I know that this exists in my array

254
00:13:31,490 --> 00:13:34,523
but it's throwing errors at me,
try putting braces around it

255
00:13:34,523 --> 00:13:37,180
and it should work.

256
00:13:37,180 --> 00:13:40,810
>> So in this case here, this is a
normal C array that we're used to.

257
00:13:40,810 --> 00:13:45,810
Has three, five, and six, and we just
want to print out the first element,

258
00:13:45,810 --> 00:13:47,850
so this should print out three.

259
00:13:47,850 --> 00:13:51,830
And I did run all these, so
hopefully nothing changed.

260
00:13:51,830 --> 00:13:54,460
We see at the bottom here,
it just prints out three.

261
00:13:54,460 --> 00:13:57,050

262
00:13:57,050 --> 00:13:58,040
Cool.

263
00:13:58,040 --> 00:14:00,000
That make sense for everyone?

264
00:14:00,000 --> 00:14:01,280
Associative arrays.

265
00:14:01,280 --> 00:14:03,150
Much cooler than normal arrays.

266
00:14:03,150 --> 00:14:09,640
>> This is why-- Did David show you
the PHP implementation of pset6

267
00:14:09,640 --> 00:14:11,751
during lecture at all?

268
00:14:11,751 --> 00:14:12,250
OK.

269
00:14:12,250 --> 00:14:13,300
So, I'll show you.

270
00:14:13,300 --> 00:14:13,770
I don't know it off the t--

271
00:14:13,770 --> 00:14:14,680
>> AUDIENCE: He did last week.

272
00:14:14,680 --> 00:14:15,560
>> ALLISON BUCHHOLTZ-AU: Was it last week?

273
00:14:15,560 --> 00:14:15,870
>> AUDIENCE: Yeah.

274
00:14:15,870 --> 00:14:16,995
>> ALLISON BUCHHOLTZ-AU: Yeah.

275
00:14:16,995 --> 00:14:20,800
So speller can be done in like six lines
with PHP, and part of the power of that

276
00:14:20,800 --> 00:14:25,640
is this associative array where
you can just load each word in,

277
00:14:25,640 --> 00:14:28,290
and you have it equal to true or false.

278
00:14:28,290 --> 00:14:31,410
And so you can say, oh.

279
00:14:31,410 --> 00:14:39,130
Return dictionary at some word, and
if it's there, it will return true.

280
00:14:39,130 --> 00:14:42,130
Otherwise, it won't find
it and it'll return false.

281
00:14:42,130 --> 00:14:45,810
So kind of a cool little thing.

282
00:14:45,810 --> 00:14:46,750
>> All right.

283
00:14:46,750 --> 00:14:48,990
So those are associative arrays.

284
00:14:48,990 --> 00:14:50,150
They're pretty cool.

285
00:14:50,150 --> 00:14:51,830
I really like them.

286
00:14:51,830 --> 00:14:55,340
And obviously this-- Ah.

287
00:14:55,340 --> 00:14:56,290
OK.

288
00:14:56,290 --> 00:14:57,880
Now it's working.

289
00:14:57,880 --> 00:15:00,700
Maybe.

290
00:15:00,700 --> 00:15:01,537
OK.

291
00:15:01,537 --> 00:15:02,120
Another thing.

292
00:15:02,120 --> 00:15:07,680
So, with equality, just a
cool thing to keep in mind.

293
00:15:07,680 --> 00:15:12,140
With PHP, because it
is dynamically typed,

294
00:15:12,140 --> 00:15:16,110
the type can change depending on when
you run it, how you're running it.

295
00:15:16,110 --> 00:15:19,890
I actually have some cool
examples that I'll show you guys.

296
00:15:19,890 --> 00:15:23,350
>> But == just checks for
equality after type juggling.

297
00:15:23,350 --> 00:15:28,890
So if you have something that's
like the character 1 and number 1,

298
00:15:28,890 --> 00:15:31,890
PHP would tell you that
those are equal because it

299
00:15:31,890 --> 00:15:35,990
can juggle the types of the
two of them until it's equal,

300
00:15:35,990 --> 00:15:38,480
which maybe for your case is fine.

301
00:15:38,480 --> 00:15:44,170
>> If you need to see if they are the
same kind of value and the same type,

302
00:15:44,170 --> 00:15:45,305
you want this ===.

303
00:15:45,305 --> 00:15:48,150
And I don't think you have any
case where you need to use that

304
00:15:48,150 --> 00:15:52,570
in your pset, but for a lot of
you who will go on to do web pages

305
00:15:52,570 --> 00:15:57,340
for your final projects and things, it's
a good thing to know that == and ===

306
00:15:57,340 --> 00:16:01,690
are different, and it's a good
distinction to understand.

307
00:16:01,690 --> 00:16:02,400
>> OK.

308
00:16:02,400 --> 00:16:02,980
So.

309
00:16:02,980 --> 00:16:04,460
Foreach loops.

310
00:16:04,460 --> 00:16:07,920
They are a way to
iterate through an array.

311
00:16:07,920 --> 00:16:11,714
So, just like arrays became
so much cooler in PHP,

312
00:16:11,714 --> 00:16:13,630
your way to iterate
through an array, I think,

313
00:16:13,630 --> 00:16:16,250
also becomes much cooler
and much more powerful.

314
00:16:16,250 --> 00:16:22,710
So instead of having to create
some for i equals 0 and whatever,

315
00:16:22,710 --> 00:16:24,890
and then update that
i as you go through,

316
00:16:24,890 --> 00:16:27,730
we have this awesome foreach loop.

317
00:16:27,730 --> 00:16:36,340
>> So here's the standard general
structure of these two.

318
00:16:36,340 --> 00:16:41,180
So you either have foreach some array
as the value you want to iterate as.

319
00:16:41,180 --> 00:16:46,750
So this is the name of the array
variable that you want to reference,

320
00:16:46,750 --> 00:16:50,600
and this is what you want
to call it within the loop.

321
00:16:50,600 --> 00:16:51,420
OK?

322
00:16:51,420 --> 00:16:56,810
So this corresponds to
each element of the array,

323
00:16:56,810 --> 00:16:59,500
and you use this value within this loop.

324
00:16:59,500 --> 00:17:00,675
>> I have an example.

325
00:17:00,675 --> 00:17:02,930
I know examples are so much better.

326
00:17:02,930 --> 00:17:05,119
And so this is if there are
no keys, so this is like

327
00:17:05,119 --> 00:17:11,170
if we just have one where the keys
are the normal indices for your array.

328
00:17:11,170 --> 00:17:14,770
Or this is also in the case if
you have no use for the keys.

329
00:17:14,770 --> 00:17:16,690
If you don't care about
the keys and you just

330
00:17:16,690 --> 00:17:20,260
want to iterate through with the values
for each of those in whatever order,

331
00:17:20,260 --> 00:17:20,950
that's fine.

332
00:17:20,950 --> 00:17:22,609
>> You can use the structure.

333
00:17:22,609 --> 00:17:28,640
Otherwise, if there are keys, our
$value just changes to $key value.

334
00:17:28,640 --> 00:17:30,660
So it just changes to a key value pair.

335
00:17:30,660 --> 00:17:34,780
And then we can refer to $key
and $value within our loop.

336
00:17:34,780 --> 00:17:35,900
OK?

337
00:17:35,900 --> 00:17:36,660
So.

338
00:17:36,660 --> 00:17:37,810
Example.

339
00:17:37,810 --> 00:17:38,610
Make it nicer.

340
00:17:38,610 --> 00:17:48,910

341
00:17:48,910 --> 00:17:49,410
OK.

342
00:17:49,410 --> 00:17:56,780
>> So we have this one
here, which we have some

343
00:17:56,780 --> 00:18:01,460
are-- You can also
create an array like this

344
00:18:01,460 --> 00:18:05,690
by having some variable equal
to array with parentheses,

345
00:18:05,690 --> 00:18:08,340
or you can just do bracket.

346
00:18:08,340 --> 00:18:11,890
You should do the bracket, but
this is another way to do it.

347
00:18:11,890 --> 00:18:16,220
So here we have some array of three
elements of one, two, and three,

348
00:18:16,220 --> 00:18:18,300
and we have our foreach.

349
00:18:18,300 --> 00:18:23,510
>> Notice this one corresponds to the
array that we're iterating over,

350
00:18:23,510 --> 00:18:28,330
and this is what we're calling
each thing in our array.

351
00:18:28,330 --> 00:18:32,670
And all this is doing is it's
going to print out each value.

352
00:18:32,670 --> 00:18:45,590
So if we run it, we notice that we
have value one, value two, value three.

353
00:18:45,590 --> 00:18:54,080
>> And in the same way that typically
arrays need to be of one type,

354
00:18:54,080 --> 00:18:57,570
arrays don't have to all
be the same type here.

355
00:18:57,570 --> 00:18:58,690
So now we have some int.

356
00:18:58,690 --> 00:19:00,910
We have two strings.

357
00:19:00,910 --> 00:19:05,332
So your arrays can
get much more powerful

358
00:19:05,332 --> 00:19:07,040
and maybe a little
bit messier, depending

359
00:19:07,040 --> 00:19:08,500
on the way you want to look at it.

360
00:19:08,500 --> 00:19:10,970
So we can change this
to whatever we want.

361
00:19:10,970 --> 00:19:12,860
We use value.

362
00:19:12,860 --> 00:19:14,630
That's just the standard thing we use.

363
00:19:14,630 --> 00:19:19,650
But, just important to know that we can
call this like counter if we wanted.

364
00:19:19,650 --> 00:19:25,070
And as long as they match up,
obviously everyone's happy.

365
00:19:25,070 --> 00:19:30,600
If you ever want to run a PHP
run something like this command

366
00:19:30,600 --> 00:19:33,800
line you know this
here, you just do PHP,

367
00:19:33,800 --> 00:19:36,090
and then whatever file you want to run.

368
00:19:36,090 --> 00:19:39,130
>> So if you want to mess around
with PHP, and more the logic

369
00:19:39,130 --> 00:19:42,710
and you don't really need to
see like in a web browser,

370
00:19:42,710 --> 00:19:44,830
you can just run it in
the command line like that

371
00:19:44,830 --> 00:19:48,290
and echo will print
out whatever you like.

372
00:19:48,290 --> 00:19:50,880
OK.

373
00:19:50,880 --> 00:20:00,640
The other way that we have is like this.

374
00:20:00,640 --> 00:20:06,974
So this is a case where maybe you want
to use both the key and the value,

375
00:20:06,974 --> 00:20:08,890
I know these are like
super contrived examples

376
00:20:08,890 --> 00:20:11,950
but I hope they make
it a little clearer.

377
00:20:11,950 --> 00:20:14,940
So here we have some array
again, but this time,

378
00:20:14,940 --> 00:20:19,450
instead of just having
you know there's no key.

379
00:20:19,450 --> 00:20:20,870
We have keys for each of these.

380
00:20:20,870 --> 00:20:24,670
So a is gonna be one, b will correspond
to two, and c will correspond to three.

381
00:20:24,670 --> 00:20:27,030
And in this case, if
we write it this way,

382
00:20:27,030 --> 00:20:31,580
we have access to both key
and value for each of these.

383
00:20:31,580 --> 00:20:36,570
>> So when we run this,
we get each of those.

384
00:20:36,570 --> 00:20:41,530
So it prints out our keys
and corresponding values.

385
00:20:41,530 --> 00:20:46,940
Another cool thing is that, and I know
said like this one didn't have keys,

386
00:20:46,940 --> 00:20:51,540
but it always implicitly has a
key because if you don't delegate

387
00:20:51,540 --> 00:20:54,050
a key, of course, your
keys are just your indexes

388
00:20:54,050 --> 00:20:59,230
or indices so we could
always also do this one.

389
00:20:59,230 --> 00:20:59,730
Like this.

390
00:20:59,730 --> 00:21:02,500

391
00:21:02,500 --> 00:21:03,400
I will print out.

392
00:21:03,400 --> 00:21:09,240

393
00:21:09,240 --> 00:21:13,420
So in this case, if you notice,
we have our implicit keys

394
00:21:13,420 --> 00:21:15,930
of zero, one, and two here.

395
00:21:15,930 --> 00:21:20,020

396
00:21:20,020 --> 00:21:25,600
>> And the same way with this one,
you can always just say r as value,

397
00:21:25,600 --> 00:21:27,910
and you just have access to the value.

398
00:21:27,910 --> 00:21:30,685
You don't care about your
keys, even if your has keys,

399
00:21:30,685 --> 00:21:32,810
if you don't care about
them, you don't necessarily

400
00:21:32,810 --> 00:21:35,970
need to put them in your foreach loop.

401
00:21:35,970 --> 00:21:37,953
Does that makes sense for everyone?

402
00:21:37,953 --> 00:21:39,764
>> AUDIENCE: Can you just
call the keys, too?

403
00:21:39,764 --> 00:21:42,180
ALLISON BUCHHOLTZ-AU: Yeah you
could totally do that, too.

404
00:21:42,180 --> 00:21:44,945

405
00:21:44,945 --> 00:21:45,570
Actually, wait.

406
00:21:45,570 --> 00:21:45,840
Hold on.

407
00:21:45,840 --> 00:21:46,630
would it-- No.

408
00:21:46,630 --> 00:21:49,663
If you want the key, then
you need to do key to value.

409
00:21:49,663 --> 00:21:50,496
AUDIENCE: Add value.

410
00:21:50,496 --> 00:21:50,870
ALLISON BUCHHOLTZ-AU: Yeah.

411
00:21:50,870 --> 00:21:52,530
And you just never use value is all.

412
00:21:52,530 --> 00:21:53,236
>> AUDIENCE: OK.

413
00:21:53,236 --> 00:21:55,610
ALLISON BUCHHOLTZ-AU: If you
just put one thing in there,

414
00:21:55,610 --> 00:22:00,010
it's going to assume that you're
talking about the value, not the key.

415
00:22:00,010 --> 00:22:02,070
Great question.

416
00:22:02,070 --> 00:22:02,600
All right.

417
00:22:02,600 --> 00:22:06,390

418
00:22:06,390 --> 00:22:08,170
Cool.

419
00:22:08,170 --> 00:22:09,032
Actually, hold on.

420
00:22:09,032 --> 00:22:09,990
Let me see what I have.

421
00:22:09,990 --> 00:22:13,600

422
00:22:13,600 --> 00:22:18,260
So before we get into post and get, I
just want to show you guys a little bit

423
00:22:18,260 --> 00:22:23,680
about how it's dynamically
typed, which is kind of cool.

424
00:22:23,680 --> 00:22:24,450
I have all these.

425
00:22:24,450 --> 00:22:28,160
I have like four examples up here,
and I will send you all this code

426
00:22:28,160 --> 00:22:30,580
after class.

427
00:22:30,580 --> 00:22:34,440
>> So here we have some variable a.

428
00:22:34,440 --> 00:22:36,500
That's just 1 plus 1, right?

429
00:22:36,500 --> 00:22:40,930
And we're going to print out what that's
equal to, and then we have some type.

430
00:22:40,930 --> 00:22:46,066
And anyone have any guesses
about what type it's going to be?

431
00:22:46,066 --> 00:22:46,890
>> AUDIENCE: An int.

432
00:22:46,890 --> 00:22:48,560
>> ALLISON BUCHHOLTZ-AU: Yeah, it's an int.

433
00:22:48,560 --> 00:22:49,890
So it just adds them together.

434
00:22:49,890 --> 00:22:51,671
It's an int.

435
00:22:51,671 --> 00:22:52,170
All good.

436
00:22:52,170 --> 00:22:56,440

437
00:22:56,440 --> 00:23:05,590
So this next one, we have
what look like strings.

438
00:23:05,590 --> 00:23:11,000
When we run this, it thinks, oh.

439
00:23:11,000 --> 00:23:13,720
You're actually trying
to just add things.

440
00:23:13,720 --> 00:23:15,140
You just got confused.

441
00:23:15,140 --> 00:23:17,410
So I'm just going to fix it for you.

442
00:23:17,410 --> 00:23:18,090
You meant int.

443
00:23:18,090 --> 00:23:19,160
I know you meant int.

444
00:23:19,160 --> 00:23:25,190
>> So this is one of the ways you can
see, PHP has a mind of its own.

445
00:23:25,190 --> 00:23:28,800
Even though we explicitly said,
look, these ones are strings.

446
00:23:28,800 --> 00:23:30,120
I mean the string one.

447
00:23:30,120 --> 00:23:32,160
But it says, oh, but
you're trying to add them,

448
00:23:32,160 --> 00:23:34,460
so you must mean it's an integer.

449
00:23:34,460 --> 00:23:35,950
Just trust me on this.

450
00:23:35,950 --> 00:23:38,920
So it says it's an integer,
and it adds them like normal.

451
00:23:38,920 --> 00:23:42,460
So kind of cool if you're going
to get lazy with your things,

452
00:23:42,460 --> 00:23:45,470
or you want to add something.

453
00:23:45,470 --> 00:23:48,690
>> A great thing is that, if
you think back to pset2,

454
00:23:48,690 --> 00:23:51,840
something that was user
inputted, right, that we think

455
00:23:51,840 --> 00:23:54,010
is a char or a string at first.

456
00:23:54,010 --> 00:23:57,950
Now we don't have to explicitly
say, oh, make this an int.

457
00:23:57,950 --> 00:23:59,790
PHP would just be like, oh yeah.

458
00:23:59,790 --> 00:24:01,215
I know you meant an int.

459
00:24:01,215 --> 00:24:01,830
Silly you.

460
00:24:01,830 --> 00:24:04,640
You didn't mean a string.

461
00:24:04,640 --> 00:24:12,596
>> So in that case, now
that we have this, what

462
00:24:12,596 --> 00:24:14,330
do you guys think it's going to do here?

463
00:24:14,330 --> 00:24:17,220

464
00:24:17,220 --> 00:24:20,495
We have a string and an int now.

465
00:24:20,495 --> 00:24:21,980
>> AUDIENCE: It's still an int.

466
00:24:21,980 --> 00:24:24,040
>> ALLISON BUCHHOLTZ-AU: It's still an int.

467
00:24:24,040 --> 00:24:26,790
And the reason is-- I would put
more examples, but this one's fun.

468
00:24:26,790 --> 00:24:30,110
The reason it's doing it is because
it's like you're trying to add things.

469
00:24:30,110 --> 00:24:33,310
So if you're trying to add
things, I'm going to assume,

470
00:24:33,310 --> 00:24:36,030
reasonably, you have something
reasonable that you could add.

471
00:24:36,030 --> 00:24:40,032
I'm just going to make it an int, and
we're just going to add it, like usual.

472
00:24:40,032 --> 00:24:42,240
And then the same way, I
think you guys get the idea.

473
00:24:42,240 --> 00:24:47,400
We also have this one here, which is
just chars, and it does the same thing.

474
00:24:47,400 --> 00:24:49,210
It's like, you silly user.

475
00:24:49,210 --> 00:24:51,400
you know you want an int.

476
00:24:51,400 --> 00:24:54,491
>> AUDIENCE: If we put a letter, will
it do the [INAUDIBLE] value or not?

477
00:24:54,491 --> 00:24:56,532
ALLISON BUCHHOLTZ-AU: Oh,
that's a good question.

478
00:24:56,532 --> 00:24:57,518
Let's see.

479
00:24:57,518 --> 00:25:00,480

480
00:25:00,480 --> 00:25:03,430
Nope, still is an int.

481
00:25:03,430 --> 00:25:06,700
So it's a little crazy.

482
00:25:06,700 --> 00:25:12,170
This is just kind of to show you PHP
can sometimes behave in irrational-- Not

483
00:25:12,170 --> 00:25:16,670
totally irrational, but it might behave
in ways that you don't really expect.

484
00:25:16,670 --> 00:25:18,970
So, when in doubt, check
the types of things.

485
00:25:18,970 --> 00:25:22,570
This function gettype
can be super useful.

486
00:25:22,570 --> 00:25:26,930
>> Typically, if you're doing anything with
plusses or any mathematical operators,

487
00:25:26,930 --> 00:25:32,010
it's going to assume anything
reasonable is just an int.

488
00:25:32,010 --> 00:25:36,530
So, you have char 1, or a
string 1, or the actual int 1,

489
00:25:36,530 --> 00:25:38,200
it's going to assume that.

490
00:25:38,200 --> 00:25:41,410
If you want to typecast
anything, you totally can.

491
00:25:41,410 --> 00:25:46,540
You could do something like
double here, I believe.

492
00:25:46,540 --> 00:25:50,370

493
00:25:50,370 --> 00:25:53,420
And in that case, it's going to say, oh.

494
00:25:53,420 --> 00:25:56,550
I'll make this a double because
you explicitly said it's a double.

495
00:25:56,550 --> 00:26:00,370
You can always explicitly
make PHP do something, but.

496
00:26:00,370 --> 00:26:02,174
>> AUDIENCE: Wait, why is A plus 1 there?

497
00:26:02,174 --> 00:26:03,215
>> ALLISON BUCHHOLTZ-AU: Oh.

498
00:26:03,215 --> 00:26:06,512

499
00:26:06,512 --> 00:26:07,490
There.

500
00:26:07,490 --> 00:26:08,400
It was just an echo.

501
00:26:08,400 --> 00:26:10,820
That was my fault.

502
00:26:10,820 --> 00:26:14,240
So, you can explicitly tell it to
make something of a certain type,

503
00:26:14,240 --> 00:26:17,980
but most of the time, it's going to
dynamically decide that at runtime.

504
00:26:17,980 --> 00:26:20,730
So it's going to keep going through
and it's going to be like, OK.

505
00:26:20,730 --> 00:26:23,229
What makes the most
sense for this to be?

506
00:26:23,229 --> 00:26:24,520
Should it actually be a string?

507
00:26:24,520 --> 00:26:25,090
Should it be an int?

508
00:26:25,090 --> 00:26:25,770
Should it be a float?

509
00:26:25,770 --> 00:26:26,810
Should it be a double?

510
00:26:26,810 --> 00:26:29,456
And it will decide that for you.

511
00:26:29,456 --> 00:26:31,980
>> You can force it to do
what you want, but--

512
00:26:31,980 --> 00:26:35,032
>> AUDIENCE: Does that make it slower?

513
00:26:35,032 --> 00:26:37,365
ALLISON BUCHHOLTZ-AU: Well,
I mean, C is very efficient.

514
00:26:37,365 --> 00:26:41,760
I think it's definitely slower because
it has to the process as it's going.

515
00:26:41,760 --> 00:26:45,200
C, I'm almost sure is faster.

516
00:26:45,200 --> 00:26:47,620
But obviously there's a
lot of cool things in here

517
00:26:47,620 --> 00:26:49,190
that we don't have to worry about.

518
00:26:49,190 --> 00:26:50,981
So, if we're searching
through an array, we

519
00:26:50,981 --> 00:26:54,290
don't have to actually create
some search through the array.

520
00:26:54,290 --> 00:26:56,920
We can just ask for the key
and PHP will take care of it.

521
00:26:56,920 --> 00:26:59,510

522
00:26:59,510 --> 00:27:00,630
>> Cool.

523
00:27:00,630 --> 00:27:01,130
Awesome.

524
00:27:01,130 --> 00:27:03,937
Looks like the end of my examples.

525
00:27:03,937 --> 00:27:05,770
You guys are never going
to forget that now.

526
00:27:05,770 --> 00:27:08,450
You're going to be like, oh, PHP is just
like that mom who's like no, no, no.

527
00:27:08,450 --> 00:27:09,325
I know what you mean.

528
00:27:09,325 --> 00:27:11,000
I know what you want.

529
00:27:11,000 --> 00:27:11,580
OK.

530
00:27:11,580 --> 00:27:15,040
So this is, hopefully, useful for your
pset, at least in the very beginning,

531
00:27:15,040 --> 00:27:20,290
because you are all about dealing
with forms and things from the user.

532
00:27:20,290 --> 00:27:24,460
>> So there are two ways that we
pass around info with PHP and HTML

533
00:27:24,460 --> 00:27:26,700
when we're passing
between those two things.

534
00:27:26,700 --> 00:27:32,330
So we have $_GET, which is passed
through the URL, and we have $_POST,

535
00:27:32,330 --> 00:27:36,600
which is passed in the message
body, and so we consider it hidden.

536
00:27:36,600 --> 00:27:41,660
But one thing to understand is that
neither of these are considered secure.

537
00:27:41,660 --> 00:27:45,580
>> If you have someone who is
intercepting the messages going

538
00:27:45,580 --> 00:27:49,180
back and forth between you and the
server, they can still get this data.

539
00:27:49,180 --> 00:27:50,810
They just have to look a little harder.

540
00:27:50,810 --> 00:27:54,690
It's not really that-- it's
just hidden from the URL.

541
00:27:54,690 --> 00:27:58,820
It's still in the message body,
though, so if they have access to that,

542
00:27:58,820 --> 00:27:59,920
it's really just like--

543
00:27:59,920 --> 00:28:01,710
>> It's like the difference
between something

544
00:28:01,710 --> 00:28:05,010
being written on the outside of
an envelope and something being

545
00:28:05,010 --> 00:28:06,980
written on a piece of paper inside.

546
00:28:06,980 --> 00:28:10,270
It's not that hard to open the envelope
and get the piece of paper inside.

547
00:28:10,270 --> 00:28:12,414
Granted, it'd be much easier
just read the outside.

548
00:28:12,414 --> 00:28:14,330
But that's how you can
kind of think of these.

549
00:28:14,330 --> 00:28:16,940
Neither of these are
really considered secure.

550
00:28:16,940 --> 00:28:17,790
OK?

551
00:28:17,790 --> 00:28:19,750
>> Granted, doesn't really
matter for your pset

552
00:28:19,750 --> 00:28:22,050
because you're not dealing
with trade secrets,

553
00:28:22,050 --> 00:28:25,850
but it's typically one
thing that we really

554
00:28:25,850 --> 00:28:29,260
like to emphasize because people
think, oh, well, it's hidden.

555
00:28:29,260 --> 00:28:30,610
It must be super secure.

556
00:28:30,610 --> 00:28:31,140
No.

557
00:28:31,140 --> 00:28:32,570
It's not secure.

558
00:28:32,570 --> 00:28:35,808
It's just slightly
less insecure, I guess.

559
00:28:35,808 --> 00:28:38,500
Or unsecure.

560
00:28:38,500 --> 00:28:41,625
>> So we actually have an example.

561
00:28:41,625 --> 00:28:43,500
As you know, I love
teach more with examples.

562
00:28:43,500 --> 00:28:45,070
I feel like this helps better.

563
00:28:45,070 --> 00:28:49,590
So, we have some simple form here
which actually, if you guys are ever

564
00:28:49,590 --> 00:28:51,940
confused about PHP,
this is really small,

565
00:28:51,940 --> 00:28:55,630
but php.net is actually
really good documentation.

566
00:28:55,630 --> 00:28:56,500
I really like it.

567
00:28:56,500 --> 00:29:02,900
I was using it to prepare for this
section, so I can vet it for you.

568
00:29:02,900 --> 00:29:07,760
>> This is an example from them
on how $_POST and $_GET work.

569
00:29:07,760 --> 00:29:09,970
The only difference
between the two of these,

570
00:29:09,970 --> 00:29:13,285
besides where the information is
displayed, whether it's in the URL

571
00:29:13,285 --> 00:29:16,430
or in the body, is also
what the method is.

572
00:29:16,430 --> 00:29:21,350
So in your form for HTML-- This
is a very simple HTML form.

573
00:29:21,350 --> 00:29:22,760
Can anyone tell me what it does?

574
00:29:22,760 --> 00:29:29,471

575
00:29:29,471 --> 00:29:30,970
AUDIENCE: Ask for your name and age.

576
00:29:30,970 --> 00:29:31,230
ALLISON BUCHHOLTZ-AU: Exactly.

577
00:29:31,230 --> 00:29:33,330
So we have some form actions.

578
00:29:33,330 --> 00:29:36,260
That lets us know it's some act form.

579
00:29:36,260 --> 00:29:39,330
And what's going to happen
is, when we hit Submit,

580
00:29:39,330 --> 00:29:44,280
it's going to call action.php,
which is what this is,

581
00:29:44,280 --> 00:29:47,180
and it's going to call it
with a method of $_POST.

582
00:29:47,180 --> 00:29:51,340
So in this case, your
information is hidden.

583
00:29:51,340 --> 00:29:57,020
and it's just your name, some
input type called name, some age,

584
00:29:57,020 --> 00:30:01,270
input type="text" that we also call age.

585
00:30:01,270 --> 00:30:05,110
And then if we hit Submit,
Submit will call action.php.

586
00:30:05,110 --> 00:30:09,800
>> So when we actually hit Submit, we
know that it has posted, per se,

587
00:30:09,800 --> 00:30:15,290
and we'll actually see this in your
problem set that hopefully we'll

588
00:30:15,290 --> 00:30:16,760
get to walk through a little bit.

589
00:30:16,760 --> 00:30:21,690
And all it's doing here is POST
is some superglobal variable

590
00:30:21,690 --> 00:30:23,300
that we talked about during lecture.

591
00:30:23,300 --> 00:30:30,170
And how you can think about $_POST is
that it's just an associative array.

592
00:30:30,170 --> 00:30:30,960
OK?

593
00:30:30,960 --> 00:30:35,930
So this is some key, this
is some key, and whatever

594
00:30:35,930 --> 00:30:39,270
the user input becomes a
value for each of those.

595
00:30:39,270 --> 00:30:39,960
OK?

596
00:30:39,960 --> 00:30:47,240
>> So if we were to write what this array
actually looked like right after we

597
00:30:47,240 --> 00:30:56,000
submitted the form, we would
have, this is our $_POST,

598
00:30:56,000 --> 00:31:04,380
and some array where we have some name.

599
00:31:04,380 --> 00:31:17,670
Let's just say we'll do my name,
and then we have some age, 21.

600
00:31:17,670 --> 00:31:19,420
Woo.

601
00:31:19,420 --> 00:31:23,550
So this is all $_POST is. $_POST
is just an associative array, OK?

602
00:31:23,550 --> 00:31:24,807
>> It just says, OK.

603
00:31:24,807 --> 00:31:26,890
What are the things we've
asked for from the user?

604
00:31:26,890 --> 00:31:28,889
What are the variables
that we're passing around

605
00:31:28,889 --> 00:31:30,730
that we've asked for in this form?

606
00:31:30,730 --> 00:31:33,830
And then what are the
values associated with that?

607
00:31:33,830 --> 00:31:38,750
So in this case, if I submitted it
with a name of Ally and an age of 21,

608
00:31:38,750 --> 00:31:40,890
this is what $_POST looks like.

609
00:31:40,890 --> 00:31:41,570
OK?

610
00:31:41,570 --> 00:31:45,150
And this is what this
PHP file has access to.

611
00:31:45,150 --> 00:31:46,680
All right?

612
00:31:46,680 --> 00:31:51,730
>> So in this case, this is just like
getting any other thing from our array.

613
00:31:51,730 --> 00:31:55,370
Instead of an index in our
array, we have some key.

614
00:31:55,370 --> 00:32:00,790
So this is going to give
me the value at key name.

615
00:32:00,790 --> 00:32:05,400
So this is going to be Ally, and
this right here is going to give me

616
00:32:05,400 --> 00:32:08,840
the value at $_POST where the
key is age, which will be 21.

617
00:32:08,840 --> 00:32:12,541

618
00:32:12,541 --> 00:32:14,290
You're going to be
doing this quite a bit.

619
00:32:14,290 --> 00:32:18,920

620
00:32:18,920 --> 00:32:21,590
Yeah, from which part?

621
00:32:21,590 --> 00:32:24,235
>> AUDIENCE: When you were
pointing at the bottom part.

622
00:32:24,235 --> 00:32:25,860
ALLISON BUCHHOLTZ-AU: This bottom part?

623
00:32:25,860 --> 00:32:26,359
OK.

624
00:32:26,359 --> 00:32:31,897
So, you understand this is our HTML
form, and we have some method $_POST,

625
00:32:31,897 --> 00:32:32,480
which matters.

626
00:32:32,480 --> 00:32:35,410
This could also be $_GET,
but for this purpose,

627
00:32:35,410 --> 00:32:36,910
we're just going to say it's $_POST.

628
00:32:36,910 --> 00:32:42,700
When we submit this form, this is
part of a PHP file that's called.

629
00:32:42,700 --> 00:32:48,530
So this PHP file is now going to execute
given the information from our HTML

630
00:32:48,530 --> 00:32:49,840
form.

631
00:32:49,840 --> 00:32:52,670
>> So what it's doing is, when we
hit Submit on our HTML form,

632
00:32:52,670 --> 00:32:59,220
it's passing you this superglobal,
which is just an associative array.

633
00:32:59,220 --> 00:33:00,306
It's this.

634
00:33:00,306 --> 00:33:02,840
It's just like passing that to the file.

635
00:33:02,840 --> 00:33:04,540
And what it says is, OK, here's $_POST.

636
00:33:04,540 --> 00:33:05,706
It's your associative array.

637
00:33:05,706 --> 00:33:07,000
Do with it what you want.

638
00:33:07,000 --> 00:33:08,980
And we're saying, OK.

639
00:33:08,980 --> 00:33:13,620
Give me the value at name,
and give me the value at age.

640
00:33:13,620 --> 00:33:18,150
>> So these are just keys,
and this is our array.

641
00:33:18,150 --> 00:33:19,190
Does that makes sense?

642
00:33:19,190 --> 00:33:19,815
>> AUDIENCE: Mhmm.

643
00:33:19,815 --> 00:33:21,266
ALLISON BUCHHOLTZ-AU: Awesome.

644
00:33:21,266 --> 00:33:24,432
AUDIENCE: If you have to resubmit the
form does it just write over the data?

645
00:33:24,432 --> 00:33:25,557
ALLISON BUCHHOLTZ-AU: Yeah.

646
00:33:25,557 --> 00:33:26,160
Mhmm?

647
00:33:26,160 --> 00:33:30,300
>> AUDIENCE: Why do you have
to specify that it's an int?

648
00:33:30,300 --> 00:33:34,950
>> ALLISON BUCHHOLTZ-AU: In this case, the
user is just forcing it to be an int.

649
00:33:34,950 --> 00:33:35,749
>> AUDIENCE: OK.

650
00:33:35,749 --> 00:33:38,540
ALLISON BUCHHOLTZ-AU: I don't know
if you would actually need that,

651
00:33:38,540 --> 00:33:43,850
but for their purposes, they decided
that they wanted it to be an int.

652
00:33:43,850 --> 00:33:45,590
They're just typecasting it.

653
00:33:45,590 --> 00:33:47,760
Maybe they're using it as
something else later on.

654
00:33:47,760 --> 00:33:49,872
This is just one snippet.

655
00:33:49,872 --> 00:33:50,372
Yes?

656
00:33:50,372 --> 00:33:57,246
>> AUDIENCE: What if they typed
12, T-W-E-L-V-E, for age?

657
00:33:57,246 --> 00:33:59,704
ALLISON BUCHHOLTZ-AU: If they
tried to type that as an int?

658
00:33:59,704 --> 00:34:00,160
AUDIENCE: Yeah.

659
00:34:00,160 --> 00:34:02,076
ALLISON BUCHHOLTZ-AU: I
forget what that does.

660
00:34:02,076 --> 00:34:05,540
I think it might try to convert
the first character to an int,

661
00:34:05,540 --> 00:34:11,360
or take the value and convert
it, but I forget exactly what it.

662
00:34:11,360 --> 00:34:14,570
Be a fun thing to write
a program and try.

663
00:34:14,570 --> 00:34:16,389
Do a couple lines.

664
00:34:16,389 --> 00:34:21,310
OK, so this is one of the main
things that you're going to be doing.

665
00:34:21,310 --> 00:34:23,969
I'm going to hopefully walk
through a couple of the files

666
00:34:23,969 --> 00:34:25,260
from the pset with you guys.

667
00:34:25,260 --> 00:34:28,850
It looks like we're going to
have time, so we can do that.

668
00:34:28,850 --> 00:34:31,190
>> But you're going to be
doing a lot of things

669
00:34:31,190 --> 00:34:36,130
like this, where you're passing
things from an HTML form

670
00:34:36,130 --> 00:34:42,130
into this PHP form that will then
execute some set of instructions

671
00:34:42,130 --> 00:34:44,460
on the data that was provided.

672
00:34:44,460 --> 00:34:46,864
That's literally the gist of your pset.

673
00:34:46,864 --> 00:34:48,130
Yeah.

674
00:34:48,130 --> 00:34:52,040
>> AUDIENCE: The type="submit", that
makes a button on the HTML form.

675
00:34:52,040 --> 00:34:54,280
Is there way to call
that button something?

676
00:34:54,280 --> 00:34:56,040
So would you be like name="submit"?

677
00:34:56,040 --> 00:34:59,170
Or is that button just going to be
empty right now, because you only

678
00:34:59,170 --> 00:35:00,970
gave it a type, not a name.

679
00:35:00,970 --> 00:35:03,803
>> ALLISON BUCHHOLTZ-AU: I think it's
just going to be empty right now.

680
00:35:03,803 --> 00:35:07,320
We can definitely look in the
pset, because we will definitely

681
00:35:07,320 --> 00:35:10,265
be looking at the
register kind of thing.

682
00:35:10,265 --> 00:35:14,610
But yeah, you can definitely specify
the text that you want on your button.

683
00:35:14,610 --> 00:35:17,560
OK, so SQL.

684
00:35:17,560 --> 00:35:21,880
>> When you're buying and selling stocks,
you need to keep track of those.

685
00:35:21,880 --> 00:35:25,760
So the way we're going to do that is
with SQL, which is just a database.

686
00:35:25,760 --> 00:35:29,200
Think of it as a table where
you're keeping all this information

687
00:35:29,200 --> 00:35:30,649
about your different users.

688
00:35:30,649 --> 00:35:32,940
And you guys are actually
going to create one of these.

689
00:35:32,940 --> 00:35:34,290
It's pretty cool.

690
00:35:34,290 --> 00:35:38,470
>> And there are just four main things
that you need to know for this pset,

691
00:35:38,470 --> 00:35:43,120
and they are update, so you
basically update the data.

692
00:35:43,120 --> 00:35:45,190
That assumes that it's already there.

693
00:35:45,190 --> 00:35:48,320
If it's not there, it's going
to hit you with an error,

694
00:35:48,320 --> 00:35:51,300
so maybe you want to check.

695
00:35:51,300 --> 00:35:55,882
And you will update on-- I
should actually- I have time,

696
00:35:55,882 --> 00:35:57,090
I'll write a couple of these.

697
00:35:57,090 --> 00:36:03,370
I will actually give you guys a
couple of sample, full SQL commands,

698
00:36:03,370 --> 00:36:06,530
because these are just the main
ones, but you can join them together.

699
00:36:06,530 --> 00:36:09,780
So I'll do that and I'll send
that out to you with these notes.

700
00:36:09,780 --> 00:36:14,580
>> So if you want to update something,
need to tell it what you're updating

701
00:36:14,580 --> 00:36:16,390
and where you're updating it.

702
00:36:16,390 --> 00:36:27,770
So a typical SQL command would be update
ID where something equals something.

703
00:36:27,770 --> 00:36:31,490
Or like update address
where ID equals 3,

704
00:36:31,490 --> 00:36:37,040
and this would update the address field
of your user who has an ID of three.

705
00:36:37,040 --> 00:36:37,630
OK?

706
00:36:37,630 --> 00:36:44,300
>> So if you go to SQL and W3Schools,
they have awesome examples.

707
00:36:44,300 --> 00:36:46,880
In fact, I might pull
some up in a little bit.

708
00:36:46,880 --> 00:36:49,810
And then insert into, you're just
inserting certain values there.

709
00:36:49,810 --> 00:36:56,810
So if you're trying to create some new
entry, so you're creating a new user,

710
00:36:56,810 --> 00:37:00,970
you could do insert into
whatever your database is called,

711
00:37:00,970 --> 00:37:03,540
and you would have all these values.

712
00:37:03,540 --> 00:37:06,250
>> Then you have select,
select values to view.

713
00:37:06,250 --> 00:37:09,640
So if you're trying to check to
see if a user exists or you're

714
00:37:09,640 --> 00:37:12,030
trying to grab specific
information about a user

715
00:37:12,030 --> 00:37:13,790
you're going to be using select.

716
00:37:13,790 --> 00:37:17,564
And then delete, I think,
is pretty simple there.

717
00:37:17,564 --> 00:37:19,480
You're just deleting
something from the table.

718
00:37:19,480 --> 00:37:25,960
And in fact, let me actually pull
up some examples for you guys.

719
00:37:25,960 --> 00:37:29,350
Oh look, it's my 61 page.

720
00:37:29,350 --> 00:37:32,940
>> So if we go to W3Schools,
hopefully it's up again.

721
00:37:32,940 --> 00:37:35,640
Yes, Love it.

722
00:37:35,640 --> 00:37:37,680
We go to SQL.

723
00:37:37,680 --> 00:37:39,160
So, this is something here.

724
00:37:39,160 --> 00:37:42,548
So, this is a very simple SELECT.

725
00:37:42,548 --> 00:37:45,620
Man, I love this function.

726
00:37:45,620 --> 00:37:50,030
So, you can have SELECT
some field FROM customers.

727
00:37:50,030 --> 00:37:55,340
In this case, customers refers to the
online database that you're using,

728
00:37:55,340 --> 00:38:00,480
so whatever your table is called, and
star just means select everything.

729
00:38:00,480 --> 00:38:01,710
Give me every one.

730
00:38:01,710 --> 00:38:05,810

731
00:38:05,810 --> 00:38:10,720
>> So, I just want to give you guys a
couple of examples of where this is.

732
00:38:10,720 --> 00:38:15,570

733
00:38:15,570 --> 00:38:17,960
So we have SELECT, UPDATE.

734
00:38:17,960 --> 00:38:21,460

735
00:38:21,460 --> 00:38:25,420
So here is kind of the general syntax.

736
00:38:25,420 --> 00:38:31,080
So UPDATE, whatever your
table name is, and then SET

737
00:38:31,080 --> 00:38:35,060
is where you're actually going
to be what data you're changing.

738
00:38:35,060 --> 00:38:38,340
So this could be-- Let
me make an example here.

739
00:38:38,340 --> 00:38:44,146

740
00:38:44,146 --> 00:38:45,145
So this is going to be--

741
00:38:45,145 --> 00:39:10,250

742
00:39:10,250 --> 00:39:10,750
>> OK.

743
00:39:10,750 --> 00:39:13,585
So I created a little database for us.

744
00:39:13,585 --> 00:39:16,260
We're going to have some ID,
some year, and some named.

745
00:39:16,260 --> 00:39:23,022
So ID one going to be year '15,
and we're just going to make it me.

746
00:39:23,022 --> 00:39:24,980
Who wants to be the second
person in our table?

747
00:39:24,980 --> 00:39:25,480
Anyone.

748
00:39:25,480 --> 00:39:28,192

749
00:39:28,192 --> 00:39:30,525
I'm just going to choose Emma
because your name's quick.

750
00:39:30,525 --> 00:39:32,220
Emma, what year are you?

751
00:39:32,220 --> 00:39:33,180
>> AUDIENCE: What year?

752
00:39:33,180 --> 00:39:33,600
>> ALLISON BUCHHOLTZ-AU: Yeah.

753
00:39:33,600 --> 00:39:34,183
>> AUDIENCE: '16.

754
00:39:34,183 --> 00:39:35,780
ALLISON BUCHHOLTZ-AU: '16.

755
00:39:35,780 --> 00:39:37,920
You're just going to be
my guinea pig for today.

756
00:39:37,920 --> 00:39:40,490
OK, so we have these two people.

757
00:39:40,490 --> 00:39:42,194
Actually, let me do this.

758
00:39:42,194 --> 00:39:45,110
Let's say I heard her wrong, and I
actually said she's a year younger.

759
00:39:45,110 --> 00:39:46,980
She's '17.

760
00:39:46,980 --> 00:39:50,790
What we want to do here, if we
wanted to update Emma's year

761
00:39:50,790 --> 00:39:57,480
to be correct using that, what we'd
do is we'd say UPDATE data over here.

762
00:39:57,480 --> 00:40:05,140

763
00:40:05,140 --> 00:40:09,130
>> And this can all be on one line, but
since I'm compressed for space here,

764
00:40:09,130 --> 00:40:11,450
I'm going to write here.

765
00:40:11,450 --> 00:40:12,740
And we want to set.

766
00:40:12,740 --> 00:40:16,770
So this is the table we're updating.

767
00:40:16,770 --> 00:40:21,600
SET is going to be what column or
what data are we actually changing.

768
00:40:21,600 --> 00:40:30,670
What we're changing is year, so
we're going to say SET year = 16,

769
00:40:30,670 --> 00:40:39,470
and then WHERE tells us which user or
what row are we actually updating this.

770
00:40:39,470 --> 00:40:40,980
>> So where?

771
00:40:40,980 --> 00:40:42,600
We have two options here.

772
00:40:42,600 --> 00:40:43,450
What are the two?

773
00:40:43,450 --> 00:40:44,580
These are unique, right?

774
00:40:44,580 --> 00:40:47,150
So our names are unique
and our ID is unique,

775
00:40:47,150 --> 00:40:50,880
so what are the two options
for where we could do this?

776
00:40:50,880 --> 00:40:51,970
I'll give you one.

777
00:40:51,970 --> 00:40:57,450
We could do WHERE ID =
2, or we could do what

778
00:40:57,450 --> 00:41:00,920
if we're going off this paradigm here.

779
00:41:00,920 --> 00:41:02,180
>> AUDIENCE: [INAUDIBLE].

780
00:41:02,180 --> 00:41:03,430
ALLISON BUCHHOLTZ-AU: Exactly.

781
00:41:03,430 --> 00:41:07,300
So we could also do name = Emma.

782
00:41:07,300 --> 00:41:10,189

783
00:41:10,189 --> 00:41:11,480
And either of these would work.

784
00:41:11,480 --> 00:41:14,040
And we ran this, it'd be like, OK.

785
00:41:14,040 --> 00:41:15,300
We'll change it.

786
00:41:15,300 --> 00:41:17,680
You're actually 16, so
now you're right again.

787
00:41:17,680 --> 00:41:21,410
OK, so this would be
super useful in your pset

788
00:41:21,410 --> 00:41:25,157
where maybe someone decided
to buy 100 shares of Apple,

789
00:41:25,157 --> 00:41:26,740
and then they were like, just kidding.

790
00:41:26,740 --> 00:41:28,320
I only want 90 shares.

791
00:41:28,320 --> 00:41:33,630
And so they sell 10 of them, so you
need to update the amount of stocks

792
00:41:33,630 --> 00:41:34,330
that they have.

793
00:41:34,330 --> 00:41:39,050
So, updating stocks, updating table.

794
00:41:39,050 --> 00:41:39,950
>> OK.

795
00:41:39,950 --> 00:41:42,710
So that's one example there.

796
00:41:42,710 --> 00:41:45,131
That's the update syntax.

797
00:41:45,131 --> 00:41:45,630
DELETE.

798
00:41:45,630 --> 00:41:50,391

799
00:41:50,391 --> 00:41:50,890
Oh.

800
00:41:50,890 --> 00:41:53,580
Insert into is our other one.

801
00:41:53,580 --> 00:41:57,950
So, this one here is very similar.

802
00:41:57,950 --> 00:42:00,430
We could just say, in this
case let's add someone.

803
00:42:00,430 --> 00:42:02,310
We can add Ben this time.

804
00:42:02,310 --> 00:42:13,300
We do INSERT INTO, and we
want the name of our table.

805
00:42:13,300 --> 00:42:16,580
In this case it's data.

806
00:42:16,580 --> 00:42:25,790
>> And then we just want, you're going to
say VALUES, and what you're going to do

807
00:42:25,790 --> 00:42:29,147
is, you actually need to make sure
that you have something for each row

808
00:42:29,147 --> 00:42:29,730
that you want.

809
00:42:29,730 --> 00:42:31,090
You just put them in order.

810
00:42:31,090 --> 00:42:33,920
So in this case, we would say 3.

811
00:42:33,920 --> 00:42:35,280
You're 18, right Ben?

812
00:42:35,280 --> 00:42:36,439
>> AUDIENCE: 19.

813
00:42:36,439 --> 00:42:37,480
ALLISON BUCHHOLTZ-AU: 19?

814
00:42:37,480 --> 00:42:38,360
AUDIENCE: 19.

815
00:42:38,360 --> 00:42:39,943
ALLISON BUCHHOLTZ-AU: Your year's '19?

816
00:42:39,943 --> 00:42:41,459
You graduate in '18, right?

817
00:42:41,459 --> 00:42:42,000
AUDIENCE: Oh.

818
00:42:42,000 --> 00:42:42,870
ALLISON BUCHHOLTZ-AU: Graduation year.

819
00:42:42,870 --> 00:42:43,842
AUDIENCE: OK.

820
00:42:43,842 --> 00:42:46,070
ALLISON BUCHHOLTZ-AU:
I was like, are you

821
00:42:46,070 --> 00:42:48,550
already planning to
take a year off here?

822
00:42:48,550 --> 00:42:52,590
So, '18, we have Ben.

823
00:42:52,590 --> 00:43:01,950
So in this case, it would go through,
it would create a new entry here.

824
00:43:01,950 --> 00:43:04,520

825
00:43:04,520 --> 00:43:05,750
Cool.

826
00:43:05,750 --> 00:43:07,570
Not too bad, right?

827
00:43:07,570 --> 00:43:09,850
A lot of this is going to
be syntax for you guys.

828
00:43:09,850 --> 00:43:13,280
Concepts should come,
hopefully, relatively easily.

829
00:43:13,280 --> 00:43:17,270
The syntax is the only thing
that can be a little tricky.

830
00:43:17,270 --> 00:43:20,590
>> And then our last one is
DELETE, and as you notice,

831
00:43:20,590 --> 00:43:22,260
I highly recommend this website.

832
00:43:22,260 --> 00:43:24,110
It's great.

833
00:43:24,110 --> 00:43:25,620
There's a ton of stuff.

834
00:43:25,620 --> 00:43:30,550
So, in the same way that we had
some UPDATE, DELETE is very similar.

835
00:43:30,550 --> 00:43:33,800
Instead we have Delete from Data.

836
00:43:33,800 --> 00:43:37,506
So in this case, our last
one I'll write down here.

837
00:43:37,506 --> 00:43:38,880
Let's say we wanted to delete me.

838
00:43:38,880 --> 00:43:44,670

839
00:43:44,670 --> 00:43:48,750
I cannot write today.

840
00:43:48,750 --> 00:43:51,720
DELETE from whatever
table we're in, data.

841
00:43:51,720 --> 00:43:56,160

842
00:43:56,160 --> 00:44:02,128
And there are actually three ways
we could choose to delete me.

843
00:44:02,128 --> 00:44:06,040

844
00:44:06,040 --> 00:44:09,780
>> Can you guys tell me what the three
ways are, how you could delete me?

845
00:44:09,780 --> 00:44:12,880

846
00:44:12,880 --> 00:44:15,400
ID equals 1, where ID equals 1.

847
00:44:15,400 --> 00:44:19,470
We could do where year equals
15, or where name equals Allison.

848
00:44:19,470 --> 00:44:21,540
of course, there are only
three different ways,

849
00:44:21,540 --> 00:44:24,570
because these are all unique.

850
00:44:24,570 --> 00:44:28,000
Typically in your table,
and especially in your pset,

851
00:44:28,000 --> 00:44:32,105
you're going to set one of
these columns to be unique.

852
00:44:32,105 --> 00:44:36,252
>> It's probably going to be some unique ID
number, because if you have-- actually,

853
00:44:36,252 --> 00:44:37,710
it might actually let you have two.

854
00:44:37,710 --> 00:44:40,520
I can't remember if it'll let
you have two of the same thing.

855
00:44:40,520 --> 00:44:42,000
>> AUDIENCE: Then it would
change their behavior.

856
00:44:42,000 --> 00:44:43,291
>> ALLISON BUCHHOLTZ-AU: It would.

857
00:44:43,291 --> 00:44:46,280
It'll cause behavior that is unexpected,
that you can't really predict.

858
00:44:46,280 --> 00:44:53,040
So you will definitely have one column
in your database that will be unique,

859
00:44:53,040 --> 00:44:55,760
and it's typically you can set
it so that it's like a unique ID,

860
00:44:55,760 --> 00:44:59,884
and it will just update every
time you insert into the table.

861
00:44:59,884 --> 00:45:02,050
Any time you create a new
row, it will automatically

862
00:45:02,050 --> 00:45:04,190
increment and give it some unique ID.

863
00:45:04,190 --> 00:45:05,960
So hint for your pset.

864
00:45:05,960 --> 00:45:08,560

865
00:45:08,560 --> 00:45:09,160
OK.

866
00:45:09,160 --> 00:45:11,575
So that is SQL.

867
00:45:11,575 --> 00:45:18,170

868
00:45:18,170 --> 00:45:22,140
>> So now we're going to talk about
the very last thing, which ties in

869
00:45:22,140 --> 00:45:24,770
actually pretty well with your
pset, if it would go forward.

870
00:45:24,770 --> 00:45:28,210
So MVC, model view controller.

871
00:45:28,210 --> 00:45:32,480
This is really just a way
to keep things organized.

872
00:45:32,480 --> 00:45:36,910
In the same way with C we ask you guys
to create functions and separate things

873
00:45:36,910 --> 00:45:42,350
out, this is just a way to separate out
code when you're doing web development.

874
00:45:42,350 --> 00:45:46,850
>> So it makes things much
more elegant and simplified,

875
00:45:46,850 --> 00:45:49,310
and this is actually the way
that your pset is actually

876
00:45:49,310 --> 00:45:52,460
set up, so whether you like it
or not, you're going to learn it,

877
00:45:52,460 --> 00:45:54,251
even if you don't think
you're learning it.

878
00:45:54,251 --> 00:45:56,580

879
00:45:56,580 --> 00:46:01,950
And one thing is, it also allows you to
do much more like a user collaboration.

880
00:46:01,950 --> 00:46:05,770
>> So when I took CS50, I did a
website for my final project,

881
00:46:05,770 --> 00:46:09,190
and I was like, I'll
handle the database stuff.

882
00:46:09,190 --> 00:46:12,450
I'll do back end stuff, and my
roommate who I was taking with it

883
00:46:12,450 --> 00:46:14,270
was very artsy.

884
00:46:14,270 --> 00:46:17,370
She does stage design, and she
wanted to make it all pretty.

885
00:46:17,370 --> 00:46:18,435
So I'm like, OK.

886
00:46:18,435 --> 00:46:20,310
You can take care of
all the front end stuff.

887
00:46:20,310 --> 00:46:22,660
>> And the thing is, as
we'll see very soon,

888
00:46:22,660 --> 00:46:26,130
that model view controller lets you
completely separate that code so

889
00:46:26,130 --> 00:46:29,260
that I could work on
implementing our pages,

890
00:46:29,260 --> 00:46:31,266
and manipulating information
in our databases,

891
00:46:31,266 --> 00:46:34,140
and she could just make things
pretty, and we were both really happy,

892
00:46:34,140 --> 00:46:36,750
because we got to do what
we both wanted and we

893
00:46:36,750 --> 00:46:38,400
didn't have to deal with the other one.

894
00:46:38,400 --> 00:46:40,377
>> So we hung out together.

895
00:46:40,377 --> 00:46:41,210
We like to hang out.

896
00:46:41,210 --> 00:46:45,649
I just didn't want to deal with
all the CSS and HTML stuff.

897
00:46:45,649 --> 00:46:46,940
I was like, you make it pretty.

898
00:46:46,940 --> 00:46:49,420
I'll deal with the database.

899
00:46:49,420 --> 00:46:52,620
So we have this really
cool, great little table.

900
00:46:52,620 --> 00:46:55,440
I love tables.

901
00:46:55,440 --> 00:46:59,680
And basically, the model you can
think about is just your database.

902
00:46:59,680 --> 00:47:03,630
>> I was the model person for my project.

903
00:47:03,630 --> 00:47:06,800
It's all about the storage of
information and organizing that data.

904
00:47:06,800 --> 00:47:09,790
So it's what we like to call back end.

905
00:47:09,790 --> 00:47:13,260
So you guys will be dealing with
the SQL database and the data files.

906
00:47:13,260 --> 00:47:14,650
That's your model.

907
00:47:14,650 --> 00:47:17,800
>> Your view, as you might
think, kind of makes sense,

908
00:47:17,800 --> 00:47:20,610
is what your user actually sees.

909
00:47:20,610 --> 00:47:22,110
It's the user interface.

910
00:47:22,110 --> 00:47:24,359
It's that front facing component.

911
00:47:24,359 --> 00:47:26,650
So that's what my roommate
got to work on all the time.

912
00:47:26,650 --> 00:47:27,660
She was super happy.

913
00:47:27,660 --> 00:47:31,580
So that's all of the HTML,
and there's very little PHP.

914
00:47:31,580 --> 00:47:34,420
>> If you're just talking about
what's being displayed to the user,

915
00:47:34,420 --> 00:47:36,576
we're talking about hypertext.

916
00:47:36,576 --> 00:47:37,950
We're talking about how it looks.

917
00:47:37,950 --> 00:47:41,400
We're not talking about logic,
or conditions, or whatnot.

918
00:47:41,400 --> 00:47:45,620
All of that gets handled
by the controller, OK?

919
00:47:45,620 --> 00:47:49,470
So that handles the user requests
and gets the information.

920
00:47:49,470 --> 00:47:54,750
>> So one thing you should know about
your pset is that, in your views,

921
00:47:54,750 --> 00:47:57,650
anything that is actually
displaying information

922
00:47:57,650 --> 00:48:00,530
should never be making
calls to your model.

923
00:48:00,530 --> 00:48:02,570
All of that is handled
in your controller.

924
00:48:02,570 --> 00:48:06,950
Your controller is the one
mediating between these two.

925
00:48:06,950 --> 00:48:10,280
It will ask the model
for certain information.

926
00:48:10,280 --> 00:48:12,610
It can iterate over that
information, figure out

927
00:48:12,610 --> 00:48:15,110
what you actually need from
it, what to do with it,

928
00:48:15,110 --> 00:48:17,860
and then it will pass on
just the information you

929
00:48:17,860 --> 00:48:24,670
need to the view for you to print it
out or display it to the user, OK?

930
00:48:24,670 --> 00:48:28,690
>> Because we see the view as
whatever is facing the user,

931
00:48:28,690 --> 00:48:31,340
so it will be much easier
for them to figure out,

932
00:48:31,340 --> 00:48:34,980
oh, if you're making
some call to your model

933
00:48:34,980 --> 00:48:39,152
and you're asking for all users
who start with the letter A,

934
00:48:39,152 --> 00:48:41,985
and you're doing that in your view,
anyone who can see your web page

935
00:48:41,985 --> 00:48:43,350
could potentially access that.

936
00:48:43,350 --> 00:48:44,740
>> You don't necessarily want that.

937
00:48:44,740 --> 00:48:48,560
You don't want people to see
more into the database than what

938
00:48:48,560 --> 00:48:49,800
they should be seeing.

939
00:48:49,800 --> 00:48:51,560
Just their specific preferences.

940
00:48:51,560 --> 00:48:53,840
So the controller handles all of that.

941
00:48:53,840 --> 00:48:59,800
So all of your .php files that we'll see
you can consider your controller files.

942
00:48:59,800 --> 00:49:02,710
And that's where you're
really going to be

943
00:49:02,710 --> 00:49:06,500
asking for things from your database,
and iterating or manipulating

944
00:49:06,500 --> 00:49:10,670
it as necessary before
passing it on to be viewed.

945
00:49:10,670 --> 00:49:12,830
>> It's a really cool pset, in my opinion.

946
00:49:12,830 --> 00:49:15,580
I think it's a little more
like instant gratification,

947
00:49:15,580 --> 00:49:17,990
because you implement a
lot of little tiny things,

948
00:49:17,990 --> 00:49:20,250
and each thing should work on its own.

949
00:49:20,250 --> 00:49:24,180
Not like, do everything
and then see if it works.

950
00:49:24,180 --> 00:49:26,570
Like with software
where you're like, I'm

951
00:49:26,570 --> 00:49:28,910
really hoping this is
right, because if it's not,

952
00:49:28,910 --> 00:49:30,743
there are a lot of
places it could be wrong.

953
00:49:30,743 --> 00:49:34,220

954
00:49:34,220 --> 00:49:35,110
>> All right.

955
00:49:35,110 --> 00:49:39,744
Just making sure that I said
everything I needed to say about MVC.

956
00:49:39,744 --> 00:49:40,680
Yeah.

957
00:49:40,680 --> 00:49:41,347
Cool.

958
00:49:41,347 --> 00:49:47,340
>> So in CS50 Finance, we have
our model, as I just said here.

959
00:49:47,340 --> 00:49:51,810
It's going to be MySQL and phpMyAdmin.

960
00:49:51,810 --> 00:49:55,130
I can definitely pull those up so
you guys get a chance to look at it.

961
00:49:55,130 --> 00:49:59,250
Like I said before, it your SQL
database acts as your model,

962
00:49:59,250 --> 00:50:03,600
and you can send what we call queries,
which are just these sorts of things.

963
00:50:03,600 --> 00:50:04,914
These are called a query.

964
00:50:04,914 --> 00:50:07,830
This is a query, where you're just
asking your database for something,

965
00:50:07,830 --> 00:50:09,810
or you're changing your
database in some way.

966
00:50:09,810 --> 00:50:11,470
That's all it is.

967
00:50:11,470 --> 00:50:16,040
And you do that with the
functions we've given you here.

968
00:50:16,040 --> 00:50:20,500
>> You can also manipulate
them by hand via phpMyAdmin,

969
00:50:20,500 --> 00:50:22,170
which we can definitely take a look at.

970
00:50:22,170 --> 00:50:25,160
I'll create a sample
database with you guys.

971
00:50:25,160 --> 00:50:25,660
OK.

972
00:50:25,660 --> 00:50:26,680
So, controller.

973
00:50:26,680 --> 00:50:30,730
So in this case, if you
notice, this is all PHP.

974
00:50:30,730 --> 00:50:33,430
Notice that's kind of your
main thing of your controller

975
00:50:33,430 --> 00:50:35,410
is that it should be mostly PHP.

976
00:50:35,410 --> 00:50:39,590
If you have HTML in your controller,
not really sure what's going on there.

977
00:50:39,590 --> 00:50:42,495
The same way as I said, if you
manage to [INAUDIBLE] with HTML,

978
00:50:42,495 --> 00:50:43,810
I'm real interested.

979
00:50:43,810 --> 00:50:49,150
>> So what we have here
is you have some query.

980
00:50:49,150 --> 00:50:53,700
Query is a function that
we built for you guys.

981
00:50:53,700 --> 00:50:56,935
It's like a wrapper to make queries
to your database a little easier.

982
00:50:56,935 --> 00:51:01,441
If you didn't have that, the syntax for
actually talking to your SQL database

983
00:51:01,441 --> 00:51:03,690
would be different, so we
just supply it for you guys.

984
00:51:03,690 --> 00:51:05,490
We like to make life easy.

985
00:51:05,490 --> 00:51:09,050
>> So in this case, can you guys
tell me what this line is doing?

986
00:51:09,050 --> 00:51:11,860

987
00:51:11,860 --> 00:51:13,487
SELECT * from some table.

988
00:51:13,487 --> 00:51:15,320
AUDIENCE: Select
everything from this table.

989
00:51:15,320 --> 00:51:16,570
ALLISON BUCHHOLTZ-AU: Exactly.

990
00:51:16,570 --> 00:51:18,750
So it's saying, give me
everything from this table.

991
00:51:18,750 --> 00:51:22,430
And it's storing it in
some variable result.

992
00:51:22,430 --> 00:51:27,720
And this says, if result is not equal
to false, then we do each of this.

993
00:51:27,720 --> 00:51:32,390
So if there's nothing here, if your
table's empty or it just doesn't exist,

994
00:51:32,390 --> 00:51:33,640
it's going to return false.

995
00:51:33,640 --> 00:51:36,431
So in this case, we're just making
sure that something was actually

996
00:51:36,431 --> 00:51:37,520
returned to us.

997
00:51:37,520 --> 00:51:40,070
>> And then here, we have
our great foreach loop

998
00:51:40,070 --> 00:51:44,380
that we're iterating over our
result, and we're calling it row,

999
00:51:44,380 --> 00:51:51,080
and we say render this template
where your data is this result.

1000
00:51:51,080 --> 00:51:52,170
OK?

1001
00:51:52,170 --> 00:51:54,440
So it's just processing
the row of the result.

1002
00:51:54,440 --> 00:51:56,790
Otherwise, it yells.

1003
00:51:56,790 --> 00:51:59,770
So, this is an example
of the controller.

1004
00:51:59,770 --> 00:52:02,842
As you see, this is the
only place-- Yeah, sorry?

1005
00:52:02,842 --> 00:52:04,960
>> AUDIENCE: Why is there
an ampersand before row?

1006
00:52:04,960 --> 00:52:07,000
>> ALLISON BUCHHOLTZ-AU:
An ampersand before row.

1007
00:52:07,000 --> 00:52:11,000
We are just iterating.

1008
00:52:11,000 --> 00:52:13,490
That's also an address of--

1009
00:52:13,490 --> 00:52:16,400
>> AUDIENCE: So it's like C referencing.

1010
00:52:16,400 --> 00:52:22,080
>> ALLISON BUCHHOLTZ-AU: It's
making sure that you're actually

1011
00:52:22,080 --> 00:52:24,730
modifying the original and not a copy.

1012
00:52:24,730 --> 00:52:28,580
It's in the same way with C where
we're passing by reference here, just

1013
00:52:28,580 --> 00:52:30,449
to make sure.

1014
00:52:30,449 --> 00:52:33,530
>> AUDIENCE: Is it not ==
instead of not = in PHP?

1015
00:52:33,530 --> 00:52:35,400
>> ALLISON BUCHHOLTZ-AU: It's not the ==.

1016
00:52:35,400 --> 00:52:37,240
>> AUDIENCE: Because equals in C is just--

1017
00:52:37,240 --> 00:52:37,970
>> ALLISON BUCHHOLTZ-AU: It's just not =.

1018
00:52:37,970 --> 00:52:38,470
Yeah, no.

1019
00:52:38,470 --> 00:52:39,656
It's not ==.

1020
00:52:39,656 --> 00:52:45,610
Because == in PHP checks for
equality with toggling, granted,

1021
00:52:45,610 --> 00:52:47,650
but extra quality.

1022
00:52:47,650 --> 00:52:51,050
So, it's not == in PHP.

1023
00:52:51,050 --> 00:52:53,025
It's one of the little
syntax differences.

1024
00:52:53,025 --> 00:52:55,330

1025
00:52:55,330 --> 00:52:55,830
Yeah.

1026
00:52:55,830 --> 00:52:57,538
So we're just iterating
through each row,

1027
00:52:57,538 --> 00:53:00,850
and render, if you guys
read through your spec,

1028
00:53:00,850 --> 00:53:05,360
is just some other function that is
actually going to process all the HTML

1029
00:53:05,360 --> 00:53:09,760
and display it in your
web browser for you.

1030
00:53:09,760 --> 00:53:10,610
>> OK.

1031
00:53:10,610 --> 00:53:15,360
So, we like to think of your controllers
as what handles the business logic.

1032
00:53:15,360 --> 00:53:18,550
As you see here, this is where we're
taking our data from the table,

1033
00:53:18,550 --> 00:53:23,530
we are processing it in some way,
and then we're passing it off.

1034
00:53:23,530 --> 00:53:27,930
When we do render some template,
some template is our view,

1035
00:53:27,930 --> 00:53:31,810
and we're passing it only
the data that it should get.

1036
00:53:31,810 --> 00:53:33,340
Not all the data.

1037
00:53:33,340 --> 00:53:35,340
Just the data that we want it to get.

1038
00:53:35,340 --> 00:53:37,520
OK?

1039
00:53:37,520 --> 00:53:40,270
Basically the data after processing.

1040
00:53:40,270 --> 00:53:44,780
>> So this is the view, this is
the sum template that we have,

1041
00:53:44,780 --> 00:53:49,810
and all this is doing is, you can
have a little PHP in your view.

1042
00:53:49,810 --> 00:53:52,620
It's not like a no PHP in view.

1043
00:53:52,620 --> 00:53:55,650
You should just have
very minimal PHP in view,

1044
00:53:55,650 --> 00:53:58,860
and you should never be
querying in your view.

1045
00:53:58,860 --> 00:54:01,580
You should never be talking
to your database in your view.

1046
00:54:01,580 --> 00:54:02,760
That's the big difference.

1047
00:54:02,760 --> 00:54:07,886
>> So what's going on here is, we have
PHP that's iterating through the row.

1048
00:54:07,886 --> 00:54:10,260
So in this case, since we were
iterating through each row

1049
00:54:10,260 --> 00:54:14,370
and rendering something, this was
probably like a two dimensional array

1050
00:54:14,370 --> 00:54:18,240
where we have some row that
is, in itself, an array,

1051
00:54:18,240 --> 00:54:20,520
because we're iterating
through it again.

1052
00:54:20,520 --> 00:54:26,730
And we're just printing out
the row name, then end it.

1053
00:54:26,730 --> 00:54:28,470
>> You shouldn't need this in the foreach.

1054
00:54:28,470 --> 00:54:30,560
I've never seen that before actually.

1055
00:54:30,560 --> 00:54:33,160
I just do foreach.

1056
00:54:33,160 --> 00:54:35,140
OK, so that's the view.

1057
00:54:35,140 --> 00:54:40,170
Let's see if we can walk through
a little bit of your pset.

1058
00:54:40,170 --> 00:54:45,380
We have 15 minutes, so I'm sure you
guys would like that more than just

1059
00:54:45,380 --> 00:54:45,935
ending early.

1060
00:54:45,935 --> 00:54:48,980

1061
00:54:48,980 --> 00:54:52,680
Let me see if I can bring this up.

1062
00:54:52,680 --> 00:54:57,130
>> So I don't know how many of you guys
have downloaded it and whatnot yet,

1063
00:54:57,130 --> 00:55:00,660
but we have username here,
and we have some password.

1064
00:55:00,660 --> 00:55:05,310
And unfortunately, right
now the database is empty,

1065
00:55:05,310 --> 00:55:10,390
so we actually need
to create a database.

1066
00:55:10,390 --> 00:55:13,470
Well, that's weird.

1067
00:55:13,470 --> 00:55:14,450
Did not expect that.

1068
00:55:14,450 --> 00:55:15,375
Technical errors.

1069
00:55:15,375 --> 00:55:17,139
Technical difficulties.

1070
00:55:17,139 --> 00:55:17,930
We have some pset7.

1071
00:55:17,930 --> 00:55:22,470

1072
00:55:22,470 --> 00:55:23,180
Cool.

1073
00:55:23,180 --> 00:55:29,660
>> So, one thing you can do is, with
a query-- I'll create a table.

1074
00:55:29,660 --> 00:55:38,570
So this is going to be users-- what
you can do here is, if we have some--

1075
00:55:38,570 --> 00:55:39,830
Really now?

1076
00:55:39,830 --> 00:55:40,330
OK.

1077
00:55:40,330 --> 00:55:44,510
Obviously I'm not doing so hot.

1078
00:55:44,510 --> 00:55:45,010
Oh.

1079
00:55:45,010 --> 00:55:45,740
I know why.

1080
00:55:45,740 --> 00:55:49,070
Because I never created
my actual tables.

1081
00:55:49,070 --> 00:55:52,400
So when you first start with
a database, you obviously

1082
00:55:52,400 --> 00:55:56,550
have to decide what are the
things I need to have in here?

1083
00:55:56,550 --> 00:56:00,850
>> So if we just go off
our data table here,

1084
00:56:00,850 --> 00:56:06,410
we had some ID, which
can just stay an int.

1085
00:56:06,410 --> 00:56:12,460
And if we look over here, there's
a cool thing that-- So index.

1086
00:56:12,460 --> 00:56:18,060
If you do primary, it will make it the
thing that your table is organized by,

1087
00:56:18,060 --> 00:56:19,410
and it will also make it unique.

1088
00:56:19,410 --> 00:56:25,790
So in this case, we'll make it primary,
and I'm going to make this name,

1089
00:56:25,790 --> 00:56:34,500
then we'll just make it a varchar
of like 26 letters, because why not?

1090
00:56:34,500 --> 00:56:39,060
>> And then you can go to Save, and then
if you see, we have some users here.

1091
00:56:39,060 --> 00:56:42,950
So if we wanted to do an
insert, we could do it

1092
00:56:42,950 --> 00:56:51,807
this way, or if you wanted practice
with your queries-- Oh boy.

1093
00:56:51,807 --> 00:56:53,140
I have not used this in forever.

1094
00:56:53,140 --> 00:56:53,980
I take this back.

1095
00:56:53,980 --> 00:56:57,620

1096
00:56:57,620 --> 00:57:04,030
>> You can edit this on your own either
just by manually inserting information

1097
00:57:04,030 --> 00:57:08,270
with something like, you
can change any of these

1098
00:57:08,270 --> 00:57:13,730
if you wanted to make-- If you want to
suddenly get rid of name, you can drop,

1099
00:57:13,730 --> 00:57:15,220
you can do all those things.

1100
00:57:15,220 --> 00:57:17,560
If you need to ever
manually change your table,

1101
00:57:17,560 --> 00:57:20,200
I suggest doing it in
phpMyAdmin versus trying

1102
00:57:20,200 --> 00:57:24,475
to figure out the SQL
queries in general.

1103
00:57:24,475 --> 00:57:27,350
When you first start your pset,
you're going to have to work in here,

1104
00:57:27,350 --> 00:57:29,650
so get used to that.

1105
00:57:29,650 --> 00:57:35,650
And then when you actually want
to insert things into your table--

1106
00:57:35,650 --> 00:57:38,310
I really wonder where that is,
because there's-- Here it is.

1107
00:57:38,310 --> 00:57:39,310
That's what I wanted.

1108
00:57:39,310 --> 00:57:44,320
So if you go to SQL, you could
actually see, as we see here,

1109
00:57:44,320 --> 00:57:45,870
we have SQL queries.

1110
00:57:45,870 --> 00:57:54,100
>> So if we wanted to select something
or if we wanted to insert something,

1111
00:57:54,100 --> 00:58:00,320
we can do insert into the users, right?

1112
00:58:00,320 --> 00:58:04,460

1113
00:58:04,460 --> 00:58:07,230
I think you need the backslash.

1114
00:58:07,230 --> 00:58:10,210
One thing to know is, if
you're ever using this,

1115
00:58:10,210 --> 00:58:14,800
you have to use these back
apostrophes, which are typically,

1116
00:58:14,800 --> 00:58:16,790
if you're on a Mac, right above tab.

1117
00:58:16,790 --> 00:58:17,840
So a good thing to know.

1118
00:58:17,840 --> 00:58:23,330
>> You could insert into users,
and we have our values, right?

1119
00:58:23,330 --> 00:58:29,700
So we have values, and our values
in this case would just be,

1120
00:58:29,700 --> 00:58:33,910
we only have an ID so we
could do one if we wanted.

1121
00:58:33,910 --> 00:58:35,320
That's weird.

1122
00:58:35,320 --> 00:58:36,730
OK.

1123
00:58:36,730 --> 00:58:41,800
So that's just like a brief
little thing with SQL,

1124
00:58:41,800 --> 00:58:48,300
but it might be more useful to actually
look at some of the files in here.

1125
00:58:48,300 --> 00:58:50,985
>> So go to Downloads.

1126
00:58:50,985 --> 00:58:51,950
Oh, not Downloads.

1127
00:58:51,950 --> 00:58:55,260

1128
00:58:55,260 --> 00:58:58,690
So, just a quick walkthrough of
what's in each of these folders.

1129
00:58:58,690 --> 00:59:03,090
It includes, we just have things
that configure your browser,

1130
00:59:03,090 --> 00:59:05,370
we have these constants,
and we have these functions.

1131
00:59:05,370 --> 00:59:10,470
If you're interested in any of them,
I recommend looking at functions.

1132
00:59:10,470 --> 00:59:17,400
One of them that is super useful,
actually is this one here, dump.

1133
00:59:17,400 --> 00:59:20,020
>> So if you use this,
it will actually just

1134
00:59:20,020 --> 00:59:23,120
print out whatever variable
that you like it to.

1135
00:59:23,120 --> 00:59:29,000
So if you are having trouble figuring
out what this array looks like,

1136
00:59:29,000 --> 00:59:31,920
or what this data actually,
how it's formatted,

1137
00:59:31,920 --> 00:59:33,280
this is a great thing to use.

1138
00:59:33,280 --> 00:59:39,889
Especially when you have a
user with multiple stock,

1139
00:59:39,889 --> 00:59:41,680
this is going to be
something great to use.

1140
00:59:41,680 --> 00:59:42,890
Because it might be formatted--

1141
00:59:42,890 --> 00:59:45,806
>> I know at least for me when I did
this pset, it was formatted in a way

1142
00:59:45,806 --> 00:59:47,210
that I didn't quite expect.

1143
00:59:47,210 --> 00:59:49,960
So I was trying to iterate over
it and trying to manipulate it,

1144
00:59:49,960 --> 00:59:52,350
but I didn't really
understand what I was doing.

1145
00:59:52,350 --> 00:59:56,830
So if you just dump it, it will
print it out to the browser,

1146
00:59:56,830 --> 00:59:59,220
and you can see exactly
how it's formatted.

1147
00:59:59,220 --> 01:00:03,530
It'll typically print it out as an
array with its keys and its values.

1148
01:00:03,530 --> 01:00:04,637
So it can help there.

1149
01:00:04,637 --> 01:00:06,720
It can also help to make
sure that you're actually

1150
01:00:06,720 --> 01:00:09,070
grabbing the data that
you thought you were.

1151
01:00:09,070 --> 01:00:12,950
So if you were like, my table definitely
says there's a user with this ID,

1152
01:00:12,950 --> 01:00:15,260
but when you go to dump the
variable, it's not there,

1153
01:00:15,260 --> 01:00:17,551
you obviously know that's
where an error's going to be.

1154
01:00:17,551 --> 01:00:22,180
This is one of the best tools
for debugging, in my opinion.

1155
01:00:22,180 --> 01:00:24,480
And then there's a
couple other things here,

1156
01:00:24,480 --> 01:00:27,660
but for the most part, that's the
one I want to draw your attention to,

1157
01:00:27,660 --> 01:00:31,060
because it is very helpful.

1158
01:00:31,060 --> 01:00:35,800
>> Public, what we have here is,
this is all of our CSS stuff.

1159
01:00:35,800 --> 01:00:40,520
So CSS, fonts, our images, whatnot.

1160
01:00:40,520 --> 01:00:43,255
This is all stuff that
you don't have to modify.

1161
01:00:43,255 --> 01:00:46,070

1162
01:00:46,070 --> 01:00:50,080
Can you guys think about if this
has things like CSS in the fonts,

1163
01:00:50,080 --> 01:00:54,039
would this be a model, or
a view, or a controller?

1164
01:00:54,039 --> 01:00:54,914
AUDIENCE: [INAUDIBLE]

1165
01:00:54,914 --> 01:00:57,080
ALLISON BUCHHOLTZ-AU: It'd
be more of a view, right?

1166
01:00:57,080 --> 01:01:00,510
This is handling all
things, how things look.

1167
01:01:00,510 --> 01:01:03,500
So if we open this here, we see
that all that's happening here

1168
01:01:03,500 --> 01:01:05,060
is we're rendering something.

1169
01:01:05,060 --> 01:01:05,820
OK?

1170
01:01:05,820 --> 01:01:09,710
So this would very much
qualify as a view for this.

1171
01:01:09,710 --> 01:01:14,810
So this is just taking some,
it's calling some portfolio.php

1172
01:01:14,810 --> 01:01:19,430
that we have, and it's passing
in title and portfolio.

1173
01:01:19,430 --> 01:01:20,696
And it's just rendering that.

1174
01:01:20,696 --> 01:01:21,820
Actually, I take that back.

1175
01:01:21,820 --> 01:01:27,890
This is a controller, because
render, remember, renders the view.

1176
01:01:27,890 --> 01:01:30,832
So portfolio.php in this
case would be your view.

1177
01:01:30,832 --> 01:01:32,480
Sorry, guys.

1178
01:01:32,480 --> 01:01:36,160
Portfolio.php is going to be
your view, and this would just

1179
01:01:36,160 --> 01:01:38,730
be your controller for that.

1180
01:01:38,730 --> 01:01:43,120
And if we take a look at this
last one here, templates,

1181
01:01:43,120 --> 01:01:47,330
templates are all of your views here.

1182
01:01:47,330 --> 01:01:52,420
So if we look, obviously
we see a lot of HTML here.

1183
01:01:52,420 --> 01:01:58,920
>> So this one is just showing you what
the login page should look like.

1184
01:01:58,920 --> 01:02:04,810
You notice we have some
form groups, have submit.

1185
01:02:04,810 --> 01:02:08,510
Here's how you decide what
is displayed on there.

1186
01:02:08,510 --> 01:02:14,320
You have some button type="submit",
and then you have what you want it

1187
01:02:14,320 --> 01:02:16,670
to display in button.

1188
01:02:16,670 --> 01:02:19,860
So that's how you would make it
show up as whatever you'd like.

1189
01:02:19,860 --> 01:02:24,520
>> And we see here we have some
username, some password,

1190
01:02:24,520 --> 01:02:30,590
and when we actually hit Submit,
it's going to be some post,

1191
01:02:30,590 --> 01:02:33,346
and it's going to post to what?

1192
01:02:33,346 --> 01:02:35,430
What's the controller for this view?

1193
01:02:35,430 --> 01:02:38,040

1194
01:02:38,040 --> 01:02:40,940
When we hit Submit,
what's going to be called?

1195
01:02:40,940 --> 01:02:42,990
Do we know?

1196
01:02:42,990 --> 01:02:45,560
It's right here, so login.php.

1197
01:02:45,560 --> 01:02:47,600
Something you guys are
going to implement.

1198
01:02:47,600 --> 01:02:50,580
>> So you can always tell
what's going to be

1199
01:02:50,580 --> 01:02:53,740
called after you hit Submit
by this first line here.

1200
01:02:53,740 --> 01:02:55,440
What the form action is.

1201
01:02:55,440 --> 01:02:58,350
When this form is submitted,
what action do we take?

1202
01:02:58,350 --> 01:03:01,440
We call login.php, and we
call it with this method

1203
01:03:01,440 --> 01:03:05,500
of post, which has the
hidden information.

1204
01:03:05,500 --> 01:03:06,210
OK?

1205
01:03:06,210 --> 01:03:14,485
So this is your view, and then obviously
if we went to login.php-- Do we have it

1206
01:03:14,485 --> 01:03:16,025
yet?

1207
01:03:16,025 --> 01:03:17,970
Yeah.

1208
01:03:17,970 --> 01:03:21,950
>> So as we see here, this
has a lot more logic.

1209
01:03:21,950 --> 01:03:23,570
It's all our PHP here.

1210
01:03:23,570 --> 01:03:28,870
We're trying to see if it was $_GET,
if it was $_POST, validating things,

1211
01:03:28,870 --> 01:03:31,370
querying, all this stuff.

1212
01:03:31,370 --> 01:03:34,950

1213
01:03:34,950 --> 01:03:40,200
So those are just the three
different things here.

1214
01:03:40,200 --> 01:03:43,750
you don't have to change things.

1215
01:03:43,750 --> 01:03:46,540
You'll be creating things
in template, possibly,

1216
01:03:46,540 --> 01:03:51,350
but as far as HTML or the
styling of any of this goes,

1217
01:03:51,350 --> 01:03:54,550
you can leave it as plain or
as intricate as you'd like.

1218
01:03:54,550 --> 01:03:59,800
>> Some people get really into it and
make some pretty awesome websites.

1219
01:03:59,800 --> 01:04:00,940
You don't have to do that.

1220
01:04:00,940 --> 01:04:03,750
If you have time, it's
a really cool thing.

1221
01:04:03,750 --> 01:04:08,260
You can mess around with CSS and HTML
and get a much better feel for it,

1222
01:04:08,260 --> 01:04:10,810
but don't feel pressured to.

1223
01:04:10,810 --> 01:04:14,760
There's plenty for you to do on the
back end with implementing log in,

1224
01:04:14,760 --> 01:04:17,170
and register, and all of these things.

1225
01:04:17,170 --> 01:04:20,490
>> So hopefully that helps a little bit.

1226
01:04:20,490 --> 01:04:23,430
do you guys have any questions
about anything we've gone over,

1227
01:04:23,430 --> 01:04:25,690
any other resources?

1228
01:04:25,690 --> 01:04:31,160
I will definitely send all of
my example PHP code to you guys,

1229
01:04:31,160 --> 01:04:35,020
and then feel free to take
pictures or whatnot of this.

1230
01:04:35,020 --> 01:04:36,180
Also it's online.

1231
01:04:36,180 --> 01:04:39,010
You can always just watch again.

1232
01:04:39,010 --> 01:04:42,190
So if that's it, everyone good?

1233
01:04:42,190 --> 01:04:42,690
Yes.

1234
01:04:42,690 --> 01:04:44,523
>> AUDIENCE: I just want
to confirm, when we're

1235
01:04:44,523 --> 01:04:47,447
doing select in SQL, the
star means everything, right?

1236
01:04:47,447 --> 01:04:48,530
ALLISON BUCHHOLTZ-AU: Yes.

1237
01:04:48,530 --> 01:04:50,446
AUDIENCE: And then if
you don't have the star,

1238
01:04:50,446 --> 01:04:53,732
if you want it to take from a specific
row, then you just put the name of--

1239
01:04:53,732 --> 01:04:55,440
ALLISON BUCHHOLTZ-AU:
The name of the row

1240
01:04:55,440 --> 01:04:56,240
and what you want you want the value of.

1241
01:04:56,240 --> 01:04:57,577
>> AUDIENCE: And then the date.

1242
01:04:57,577 --> 01:04:59,910
ALLISON BUCHHOLTZ-AU: Whatever
you're looking for, yeah.

1243
01:04:59,910 --> 01:05:05,100
In the same way, if you do DELETE * from
some table, it'll delete everything.

1244
01:05:05,100 --> 01:05:08,896
So, * is just a wild
card for everything.

1245
01:05:08,896 --> 01:05:09,788
>> AUDIENCE: OK.

1246
01:05:09,788 --> 01:05:10,930
>> ALLISON BUCHHOLTZ-AU: Cool.

1247
01:05:10,930 --> 01:05:11,430
Awesome.

1248
01:05:11,430 --> 01:05:12,800
Well, have a great Monday, guys.

1249
01:05:12,800 --> 01:05:13,760
I'll see you next week.

1250
01:05:13,760 --> 01:05:15,530
Good luck on your pset.

1251
01:05:15,530 --> 01:05:16,992