Beginner PHP Tutorial - 29 - die and exit Functions Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

now this Alex from PHP academy' to org
and welcome to another video tutorial
for the new Boston now I'm going to be
talking about PHP die and exit and these
are two really useful functions that you
should get used to using in your program
so you can cut the script at any point
where you may receive a fatal error
in which you don't want to execute any
more code now let me just show you
demonstrate how this works let's say I
want to echo out hello and a space and
down here I want to echo out a space and
world now if we were to run this if we
to run this normally refresh our browser
you can see it will just produce the
result hello world because we've
included hello with a space and we've
included world now let me just use the
die feature in here and what this is
going to do is it from this point
onwards is going to kill the rest of the
page
okay so let's have a look at the result
in the browser okay so we're just
receiving the string hello now why is
this useful
I mean Barrowman you can also use exit
as well and this does exactly the same
thing if we refresh we're getting the
same result now why would we want to
kill our script in the middle of a page
I mean first of all dottie using dine
exit exactly the same thing bear in mind
you can also part of this function you
can specify an error in here so you can
use some string to output so error page
has ended for example and let's just
echo again the world part of this page
so if we refresh you can see that we've
received this message so you can do that
if you want and you can do exactly the
same thing with exit as well
and we go same thing so how do we use
this in a real-life example and why is
it useful
okay so without overcomplicating things
I'm going to attempt now to connect to a
database now whether you've come across
databases yet or not this is an example
to show you how died or exit can be used
now to connect to a MySQL database we
use the MySQL connect function and we
supply it with three I mean we've looked
at functions anyway so that you should
really understand this at this point and
anyway so I'm connecting to localhost my
username is Alex and I don't I don't
specify a password because I'm running
on a local server so what do I do if
this is wrong now at the moment if i
refresh the page
nothing oh okay Oh No okay so sorry my
username is root so I've already
produced myself an error so if i refresh
there okay so that's that's connected
absolutely fine so we know that that's
connected because we've not received an
error that might not necessarily be the
case but I know that my username is root
my password is blank and the and I'm
connecting to my local server so what
happens if we want to specify our own
error if this hasn't connected so for
example or die could not connect to
database what I've essentially done here
is used or so it's a logical operator
we've said or you can also say or like
this so or die if this is unsuccessful
we want to die and produce this error to
the page so at the moment nothing's
happening so I can echo down here
connected and I refresh and a refresh
and I received the error the message
connected now what if I change this
around so I want to connect to in fact
let's just change this back to Alex
because I know that's not my username
now when i refresh you can see that
we've killed the page this has produced
an error and we've specified our our own
error as well now what if we want to get
rid of this error and we just want to
display this error
we've already displayed user-friendly we
just pop an apt before just pop an Apps
beforehand now when we refresh we
basically are just left with could not
connect database so this is essentially
a user friendly way of connecting to the
database or killing the page obviously
we're not now outputting connected
killing the page and saying could not
connect to database so that's
essentially what we've done like I said
before you can replace that with the
double vertical lines and it will do
exactly the same job we're just using
logical operators there which we've
already covered so you've now seen a
real-life example of where you can use
die obviously this can also be exit so
if we refresh the page it is exactly the
same thing could not connect to database
so that is basically the die and exit
functions within PHP and how useful they
can actually be