Django Tutorial for Beginners - 10 - Filtering Database Results Video Lecture | Django: The Ultimate Beginners Guide - Back-End Programming

do you remember at the beginning of the
video where I tried to print out all the
objects or all the album's let's go
ahead and try do that again now that we
have some albums in there so album
objects all alright so you can see that
we have two albums or two objects in our
database so this one in this one however
I mean unless you're a computer this
isn't really useful information
they just say album object album object
and whenever I printed out these objects
I was kind of you know hoping for like
the album title or like the artist or
something other than this generic thing
I mean I know that it worked is just
that we don't have a really detailed
explanation of what these albums are so
let's go ahead and fix that right now so
if you actually go over to music models
go ahead in your class album and what we
need to do is we need to specify hey
whenever we're looking through the bad
base and we say give me all the elbows
we just don't want to say oh okay
there's the album object no what we want
is I don't know maybe the album title
and the artist so how do we do that well
we can make a special method called
under string now when I say dunder I
mean double underscore and what this
method is is a built in syntax that
means a string representation of this
object so we already know that we can
you know get the album title
specifically or the artist well what
happens when we just print out the album
well what's that mean do you want
everything you just want part of it this
is where we specify what it's supposed
to print out and there are no rules to
what you have to print out you can kind
of just print out whatever makes sense
so what I'm going to do is I'm just
going to return self and I'll say uh
album title and maybe I will let's do
this let's print out the album title and
we'll also print out the um I don't know
artist so self artist re so what we're
going to have to do after this is we
need to exit the show now we need to
exit
because we need to restart it anytime
you make changes to your models what it
does is it still has the old structure
in there so anytime you want to exit
this just go ahead and right exit the
exit function and that does that and let
me clear this and give us a new screen
now if you guys remember how to start it
up
Python managed Qi shell and remember the
first thing that we always need to do is
we need to import those models so from
music models import album and song
alright so now let's go ahead and try to
print our album objects all re so that's
a little bit better now it does is it
prints out read Taylor Swift high school
myth and it did this because we didn't
save middle school again so you see it I
was talking about unless you hit save it
doesn't explicitly save your data it
just shaped saves it in the shell it's
about to say shaves it in the cell which
would be kind of weird but anyways there
you go now a couple last things I want
to talk to you guys about maybe three
more examples is you can actually look
up specific albums and you can do this
in a couple of different ways whenever
we get to it in code I'm going to show
you like the useful ways but now I just
want to kind of show you guys what this
is capable of so what this is going to
do is it's going to get all the objects
but what we want to do is we just want
to filter some specific ones out so the
criteria is let's go ahead and get the
album's with the ID of one and that's
just going to be Taylor Swift so there
you go of course you can do it with two
if you do it with something like three
that doesn't exist
so of course you don't get any results
now another cool filter that you can use
is if you say something like album what
was the album title I think now let's
get up let's get artist
so we'll say we're going to filter with
artists double underscore starts with
equals uh Taylor so there you go it's
going to look through all of your albums
and find the artist whose name starts
with Taylor and I don't know if you guys
can see it but between artists and
starts with there's actually two
underscores so just remember that so the
reason that I'm teaching you guys this
is because if you ever want to add
objects or delete them from your
database then this is a really
convenient way also the code that we
wrote for example just right here this
isn't a specific to your Python data API
shell this is the exact code that we're
going to be writing in here so it's the
same thing it's just a lot faster and
easier to play around with it when you
get your results instantly and you don't
have to refresh any page over and over
again so anyways that is your
introduction pretty cool I'll see you
guys next video