Django Tutorial Walkthrough 2

Part 2 of a coding walkthrough of the Django web framework's official tutorial: https://docs.djangoproject.com/en/4.0/intro/. You may follow along if you are learning too.

Transcript

The following transcript was automatically generated by an algorithm.

00:00 : welcome to part two of the code tutorial
00:03 : walkthrough for the django web framework
00:05 : uh i
00:06 : uh in the previous video we done part
00:09 : one of the tutorial which is that uh
00:12 : this time we're gonna do part two okay
00:17 : and here we're going to do some database
00:20 : setup if you want to use a database
00:25 : such as postgresql or oracle or
00:28 : mysql or mariadb
00:32 : you can set that up
00:33 : or if you just want to use
00:36 : sqlite
00:38 : which just
00:40 : comes bundled with the django framework
00:42 : itself
00:43 : you can also do that and then you don't
00:45 : have to do anything i'm gonna choose the
00:48 : not do anything option
00:50 : and use sqlite
00:52 : i'm familiar with sqlite myself
00:56 : i'm also familiar with postgres sql uh
00:59 : perhaps later on i might
01:02 : i might show how to switch the database
01:05 : vendor but for now i'm going to stick
01:07 : with sqlite
01:10 : uh but but uh having said that i'm going
01:13 : to open up
01:15 : the settings.py so
01:18 : my site.settings py uh my project is
01:21 : called django touch so
01:23 : i would find it under django tut
01:25 : settings py
01:29 : there's a time zone
01:31 : that might matter for
01:34 : certain databases
01:36 : but it's the engine
01:39 : there we go so for databases um
01:42 : we can change what the default is i
01:45 : guess you can also have multiple
01:47 : databases configured
01:49 : but the default currently is sqlite 3.
01:52 : so if i wanted to change it to say
01:55 : postgres sql
01:57 : i could just change this like that but
02:00 : if i had changed it like that i would
02:02 : need to put in some other configuration
02:05 : specifically for postgresql as well
02:09 : but
02:10 : at the moment i'm not gonna do that i'm
02:12 : gonna stick with a sequel light
02:17 : okay
02:18 : so
02:19 : um
02:20 : so i'm gonna stick with sqlite and we're
02:23 : going to actually migrate perform this
02:26 : migrate command and what is migrate
02:29 : let's talk about that
02:31 : why are we migrating um
02:34 : the term migrate means
02:38 : we're migrating a from an older version
02:42 : of
02:43 : the applications database
02:46 : to a newer version
02:48 : a new yeah yeah a new version of the
02:51 : applications database so you might
02:55 : imagine
02:57 : um
02:59 : your old version of the database
03:05 : so i'm gonna call it v1
03:08 : maybe the the first version of your
03:10 : application uh it maybe it supports
03:13 : users
03:17 : uh maybe it supports uh projects i don't
03:20 : know maybe this is a project
03:22 : management application
03:25 : and that's it
03:26 : but
03:27 : um
03:28 : but maybe v2 version two
03:34 : a newer version of your application
03:37 : maybe you support more than that
03:42 : you you support users projects but in
03:45 : addition to that
03:47 : maybe your project's got additional
03:50 : fields in it so like maybe version one
03:53 : it has
03:55 : project id project name
03:58 : and in the next version you have project
04:00 : id name
04:02 : and description
04:08 : and maybe you also have additional
04:10 : tables as well um
04:12 : maybe you added a uh another table
04:15 : called
04:17 : i don't know
04:19 : badges
04:20 : you know because
04:21 : because
04:22 : every app has to have badges
04:25 : um
04:26 : if that was the case then
04:29 : what you would end up doing is basically
04:32 : you have certain
04:36 : you have certain things
04:40 : that
04:41 : are different
04:42 : uh
04:43 : certain changes you made to the database
04:47 : um
04:48 : which your version two has that your
04:50 : version one does not and what migrate
04:53 : does is takes a version one database and
04:56 : migrates it to
04:58 : version two uh and in particular what
05:02 : it'll do is add the bits
05:04 : that were added in
05:07 : in the
05:08 : in the updating of from version one to
05:11 : version two so
05:12 : um
05:14 : so
05:15 : that's what migrate
05:17 : conceptually does let's actually
05:20 : do
05:21 : perform this command and actually see
05:24 : what it does
05:28 : i hope i explained that okay
05:31 : okay
05:32 : so it actually has
05:34 : applied a whole bunch of
05:37 : things
05:38 : a whole bunch of migrations so it
05:42 : each one of these lines is a
05:44 : migration
05:46 : and i believe there are actually files
05:49 : although i don't see them in my project
05:51 : let me see
05:53 : do i have migration files
05:58 : no i don't so these must be like
06:01 : default migration files that are
06:03 : internal to django but are not in my
06:06 : project but these are like
06:08 : default
06:10 : things that every django application has
06:12 : it has users rows
06:15 : um
06:17 : a bunch of stuff that come right out of
06:19 : the box for django um
06:22 : in particular django has this
06:24 : admin
06:26 : functionality which we'll see later
06:29 : and i i bet
06:31 : most of these are used for that
06:33 : functionality
06:34 : but we'll see that later but essentially
06:37 : what it did though
06:39 : was actually create some database tables
06:44 : in our database and since our database
06:48 : is
06:49 : currently a sqlite database
06:54 : i i do want to give a shout out to
06:56 : sqlite because
07:01 : in my opinion sequel light is an awesome
07:04 : project and i have used it with success
07:08 : on other projects that i am working on
07:11 : so
07:12 : in django bundles
07:14 : uh sqlite within itself and
07:18 : so
07:19 : um and
07:21 : you can see that when
07:24 : after this migration happened
07:27 : um we
07:29 : basically brought a database from
07:31 : version zero
07:33 : to version one now where version zero
07:35 : didn't even have anything
07:37 : we've migrated a
07:39 : non-existent database to a version one
07:42 : database that actually has tables in it
07:44 : and those tables are in here in the
07:47 : sqlite 3 database and this db.sqlite3
07:51 : is a file but it's a file that contains
07:54 : everything that
07:56 : that database needs and we can actually
07:58 : take a look
08:00 : inside that database
08:01 : um you can
08:03 : if you have sql lite installed um you
08:07 : can do this
08:08 : and if you don't have sqlite installed
08:10 : you can install sqlite and then do this
08:13 : okay
08:14 : um
08:16 : so i'm going to do sqlite 3
08:19 : db dot sqlite3
08:22 : and then we're in this database and you
08:24 : can see all the tables so
08:28 : i can use the corresponding command
08:30 : depending on which database i'm using
08:32 : sqlite so i should use dot tables
08:36 : to see what tables exist here okay so
08:40 : these are all the tables that exist
08:43 : and
08:43 : [Music]
08:45 : yeah
08:46 : we have django session django migrations
08:50 : oh i can probably select
08:52 : from django
08:55 : migrations
08:56 : to see what migrations are there and
08:58 : these are all the migrations that got
09:01 : applied to this database
09:04 : and
09:04 : [Music]
09:07 : what other things can we look at here
09:11 : we can maybe look at the auth users
09:18 : there are no off users at the moment
09:21 : okay there's another cool uh sqlite tool
09:25 : that i have
09:26 : uh installed for this is mac only
09:29 : however
09:30 : it's called db browser for sqlite
09:37 : so if you're on mac you can use this uh
09:40 : if you're not on mac
09:42 : i
09:43 : pretty sure there are comparable tools
09:46 : like this for windows on or linux
09:49 : but i'm using mac so i use this so what
09:51 : i can do is open up a database
09:55 : and i can navigate to
10:05 : oops
10:11 : navigate to this sqlite3 database file
10:14 : and open it up
10:16 : and now
10:18 : i have a
10:20 : gui
10:21 : a
10:22 : graphical user interface with which
10:26 : to
10:27 : look at the different tables look at the
10:29 : table
10:30 : structures and i can also browse the
10:32 : data within these tables
10:36 : um
10:39 : like this so this is the migrations
10:41 : table which probably is one of the few
10:44 : oh we also have these
10:46 : rows or these oh these are django
10:48 : content types
10:51 : uh
10:52 : there aren't a lot of data in here oh
10:54 : there's auth permission there's all
10:57 : these permissions
10:58 : seeded already in the database so you
11:01 : can take a look around if you're curious
11:03 : at
11:04 : what
11:06 : django has created as it's basically
11:09 : starter database
11:12 : um okay
11:15 : and for minimalist um so some people
11:19 : may not want all this stuff created it's
11:22 : like what is all this do i really need
11:24 : it
11:25 : um is it
11:26 : really useful to me
11:28 : if if you don't want all these things
11:31 : created you can actually turn them off
11:34 : if you want
11:37 : [Music]
11:39 : so in this
11:40 : settings.py file there's a variable
11:44 : called installed apps
11:47 : and these are all the apps
11:50 : these are all the apps that are
11:51 : installed
11:52 : and
11:53 : they come from this django concrete
11:57 : contrib
11:58 : module and i would assume that all of
12:01 : these are basically for the purpose of
12:05 : serving up the django admin app which
12:08 : you will see later
12:11 : and if you think you don't need the
12:12 : django admin app you can by all means
12:14 : delete all of these and then it wouldn't
12:16 : have created all those tables that we
12:18 : saw
12:20 : but i'm going to keep that around
12:22 : you'll see the powerfulness of the
12:24 : django admin app
12:26 : in a bit
12:27 : okay
12:28 : now we're going to create some database
12:30 : models
12:37 : uh which essentially defines your
12:40 : database layout with some additional
12:44 : metadata
12:45 : and the philosophy of django is a model
12:48 : is the single definitive
12:50 : source of information about your data
12:53 : it contains the essential
12:55 : fields and behavior of the data that you
12:57 : are storing
12:59 : django follows the dry principle the way
13:02 : the goal is to define your data model in
13:04 : one place and automatically derive
13:06 : things from it
13:09 : this includes the migrations
13:12 : unlike ruby on rails for example
13:14 : migrations in ruby on rails i believe
13:17 : you
13:19 : developers are expected to hand code
13:21 : migrations
13:22 : whereas in django the migrations are
13:25 : automatically generated
13:27 : based on uh the difference of
13:30 : your model
13:32 : uh from the previous version of the
13:34 : model i believe that's the difference
13:36 : that they are highlighting
13:39 : okay so we're going to create a couple
13:40 : of models i'm going to go into our pose
13:43 : application
13:44 : and open up the models
13:46 : dot py file and here
13:49 : we
13:50 : we want to create two models the
13:52 : question model and the choice model so
13:54 : i'm going to type these in
13:59 : and if it's a model then it has to
14:02 : inherit from a
14:05 : models data model where models is a
14:08 : djangle.db.model
14:11 : and here in the class
14:15 : scope
14:17 : we type in a bunch of fields
15:00 : okay this is actually a foreign key
15:03 : that points from the choice table to the
15:06 : question table so so yeah each each
15:08 : model will end up becoming a database
15:11 : table
15:12 : and a foreign key is a
15:15 : a a pointer from one table in this case
15:18 : choice
15:19 : to another table in this case question
15:24 : and i'm not going to go into too much
15:27 : detail about um
15:30 : relational databases uh i i
15:34 : unfortunately
15:35 : um because that could be a whole
15:38 : separate course
15:41 : and in this video i'm not prepared to
15:44 : give that
16:02 : default equals zero okay
16:06 : so we have two models aka two tables and
16:10 : each model has
16:13 : a bunch of fields aka
16:16 : columns
16:18 : so so yeah so it's like um
16:21 : it's like there's orm speak
16:26 : orm
16:27 : terminology versus a sql terminology or
16:32 : a relational
16:34 : terminology so in orm speak
16:38 : we have models
16:41 : but in sql we just call them tables
16:45 : um
16:46 : in orm we have fields
16:50 : and in sql we have columns
16:53 : okay so this this is how the terms
16:57 : translate and but essentially they mean
16:59 : the same thing
17:11 : each field is represented by an instance
17:15 : of a field class so this a char field is
17:19 : a field a daytime field is a field and
17:21 : even a foreign key is a field
17:24 : um
17:24 : [Music]
17:26 : there will be end up being a translation
17:28 : from this field object to an actual
17:33 : database column and
17:35 : the type the data type on the column is
17:38 : actually determined by
17:40 : what kind of field it is and what kind
17:43 : of
17:44 : parameters you gave to the definition to
17:47 : the of the field um and you can further
17:50 : configure it
17:51 : like this on delete cascade it ends up
17:54 : getting translated to a um
17:57 : database constraint that says when you
18:00 : delete a choice object
18:03 : you should
18:04 : also delete the question
18:08 : maybe or or is it the other way around i
18:10 : think it might be the other way around
18:12 : where
18:12 : if a
18:14 : question if the parent
18:16 : question so like a question and a choice
18:18 : would be like
18:19 : hey what
18:22 : is
18:23 : one plus one and then you have choices a
18:28 : one
18:28 : b
18:29 : two
18:30 : c is three let's let's say so these this
18:33 : is the question and these are
18:36 : this is choice one choice two choice
18:39 : three
18:40 : uh this cascade on delete means if this
18:44 : question gets deleted from the database
18:47 : we're going to cascade delete and delete
18:51 : the all three of the choices that are
18:54 : related to uh this question because
18:57 : we're gonna have this choice that points
19:00 : all three of these choices
19:02 : pointed or
19:04 : had a parent of this question and their
19:07 : existence is no longer meaningful after
19:10 : their parent question goes away so
19:14 : uh so when
19:16 : yeah so that's what a cascading delete
19:18 : means as far as i understand it
19:21 : um
19:22 : and then this is a char field it's just
19:25 : a string field
19:27 : and then about this is an integer field
19:30 : and there's we also have a date field
19:31 : here
19:33 : okay
19:34 : so
19:35 : let's activate
19:37 : these models so we're going to turn
19:39 : these
19:40 : model definitions
19:42 : into actual database tables and the way
19:44 : to do that is
19:48 : what is it
19:49 : what is it i'll give you a minute i'll
19:52 : give you a second to come up with the
19:54 : answer
19:55 : the answer is
19:57 : migrate we're going to use migrate to
19:59 : actually bring the application from
20:03 : version number one of the database that
20:05 : doesn't have a question table and
20:07 : doesn't have a choice table to version
20:09 : two
20:10 : which does have these tables
20:13 : so oh before we do that though
20:16 : we have to go to the settings
20:19 : dot py
20:21 : and add
20:24 : at our polls app
20:31 : to our list of installed apps
20:36 : so if we go to our polls apps
20:39 : is here
20:41 : so there's this post config
20:44 : which apparently
20:46 : we need to include in here
20:49 : um and that's what's needed for this
20:52 : migration thing to work and now we're
20:54 : going to run make migration
20:57 : before we actually run the migrate
20:59 : command we actually need to make the
21:01 : migrations first
21:03 : for the mic
21:04 : for the mic great to have some
21:06 : migrations to migrate
21:10 : we'll we'll look at like we'll look at
21:13 : what those migrations actually look like
21:16 : okay so we're gonna
21:18 : do this command uh paste on manage py
21:21 : make migrations polls we're just gonna
21:24 : make the migration
21:26 : for the polls application
21:31 : and that's our migration that it created
21:34 : uh
21:35 : basically it's a description of what
21:37 : we're going to do to the database
21:40 : if we bring
21:42 : um a database from the previous version
21:44 : to this one
21:46 : and
21:46 : those operations are we're going to
21:48 : create a model uh it's going to have
21:51 : uh
21:52 : the model's name is question and it's
21:54 : going to have these fields we're going
21:56 : to create another model called choice
21:57 : and it has these fields that's what this
22:00 : migration is going to do
22:02 : now that we have this migration we can
22:04 : migrate
22:07 : oh it's telling us that this command is
22:09 : not
22:10 : necessary but it's it's a instructive
22:13 : it's for educational purposes
22:15 : um so i'll do that
22:17 : for educational purposes because this
22:20 : video is
22:21 : educational in nature
22:25 : so i'm going to run
22:27 : run
22:28 : sql
22:30 : migrate.001 and this will actually show
22:32 : you
22:34 : what the sql statements
22:36 : look like when we translate
22:41 : this initial
22:43 : migration this zero zero zero one
22:45 : migration
22:48 : to get the database to do these things
22:51 : create these two models
22:53 : we're going to need to create a table
22:56 : called post underscore question so this
22:59 : the table names are kind of name spaced
23:01 : by the app name so in this case polls
23:04 : and these are all the fields that are
23:07 : going to exist in this polls question
23:09 : table and then we'll also create the
23:11 : polls choice table as well with all of
23:14 : its fields and all of these is written
23:17 : in a sequel that the sequel light
23:20 : dialect of sql and it's going to work on
23:23 : our database if we run this
23:26 : sql directly on the database but it
23:28 : hasn't done it yet
23:30 : it's showing you what it's going to do
23:33 : when you actually migrate which should
23:35 : be the next thing we do now yeah let's
23:38 : go ahead and do that
23:40 : and it's it's written uh uh it's it's
23:43 : going through all the sequel in detail
23:46 : which i'm not gonna bother doing i'm
23:47 : just gonna go right ahead and migrate
23:55 : okay so this should so it has applied
23:59 : this migration
24:01 : and then that those tables should be in
24:03 : my database now
24:04 : so i'm gonna
24:05 : go ahead to my database browser for
24:08 : sqlite again
24:10 : and i'm gonna open up that
24:13 : same database and now it has a pulse
24:16 : choice table
24:18 : it has
24:20 : id choice text votes question id and the
24:22 : post
24:24 : question table as well it has three
24:26 : fields
24:39 : one thing to mention is uh these
24:42 : migration files uh you're expected to
24:44 : check them into your source control
24:48 : and
24:49 : and code review them as well
24:52 : if you're working in a team
24:55 : okay
24:57 : now we're gonna explore the shell
25:00 : so the django
25:03 : framework gives you this very
25:07 : nice and nifty and convenient
25:10 : interactive shell interactive python
25:12 : shell
25:14 : which is similar to what happens when
25:16 : you type python
25:18 : you can just type python code and it'll
25:21 : hit enter and it'll execute
25:23 : the code this is also called a repo
25:27 : read eval
25:29 : print loop
25:31 : so read eval print
25:35 : loop
25:36 : uh rebel
25:38 : um
25:39 : this is what it is we're gonna have one
25:41 : for
25:42 : django
25:43 : so and and this is how you do it you do
25:46 : python managed ipy and then shell
25:50 : and now you have a shell
25:52 : but with access to the internals of your
25:56 : django application so one thing you can
25:58 : do is you can say from polls
26:01 : that models import
26:03 : your models choice and question
26:08 : okay
26:09 : you can say question.objects all
26:15 : and that queries for all the question
26:19 : objects but currently we don't have any
26:22 : we could create them though
26:24 : um
26:28 : let's so this is saying we're going to
26:30 : import the time zone
26:32 : or
26:33 : the time zone mod
26:34 : module so we can create a new question
26:37 : object
26:39 : with
26:40 : this question text
26:43 : what's new question
26:46 : and the publish date we're gonna set
26:48 : that to
26:50 : time zone dot now
26:53 : and now i have a question object now
26:56 : um
26:59 : okay that's a representation of the
27:00 : timezone and we're gonna save that
27:03 : timezone object
27:04 : and presumably
27:06 : now it's in the database
27:08 : um and if i go question
27:11 : [Music]
27:12 : that uh
27:14 : what was it
27:16 : question.objects.org
27:19 : now we get that back and also if i go
27:22 : into the
27:24 : go into my database browser and i go
27:27 : into the question
27:29 : table i can actually see there's data in
27:32 : there and this this is what i just
27:34 : created so
27:36 : that's very cool uh the code is
27:38 : interactive and i can interact with the
27:40 : database directly using django's uh data
27:44 : model
27:46 : classes
27:48 : um it is saying it's not so nice like
27:52 : this
27:53 : representation this text representation
27:55 : of a question object is not super
27:58 : helpful so what we could do
28:00 : is add these
28:03 : override
28:05 : methods
28:06 : the thunderstring
28:08 : methods and have it return the text of
28:11 : the question
28:13 : and if we did that
28:15 : then the representation of the question
28:18 : would be
28:20 : shown
28:21 : directly here in in the shell
28:25 : let's go ahead and do that
28:27 : i thought it was wrapper
28:30 : but they're saying to use thunder string
28:34 : i might try wrapper as well
28:48 : okay so for the question we're gonna use
28:50 : the sort of
28:52 : text of the question um
28:54 : and show it for the choice we're gonna
28:58 : show the choice
29:00 : text
29:02 : and now if i run this
29:04 : i might have to restart the show
29:07 : to get it to
29:10 : okay
29:11 : i'm gonna get back
29:14 : the models and say question.objects.org
29:20 : uh
29:22 : objects plural
29:25 : now it says question colon what's new
29:28 : cool
29:30 : um i wonder if i did
29:33 : wrapper instead of string
29:37 : would it
29:38 : work try it again
29:46 : if i do wrapper then
29:49 : i see it doesn't put question colon in
29:52 : front of it i see okay
29:56 : all right i'll go back to the string
29:58 : just to
29:59 : do it the django way
30:02 : so this is saying we can also add a
30:05 : method
30:07 : to
30:08 : the question class and then that adds
30:11 : more functionality
30:13 : to the class so let's
30:16 : do that as a test
30:18 : um this is saying my published
30:22 : date
30:23 : if it's greater than now
30:28 : minus one day
30:31 : okay if it's
30:33 : publish
30:35 : it is published within 24 hours then it
30:37 : was published
30:39 : recently so if you do that
30:41 : and then go back to the shell
30:47 : it's like
30:48 : question
30:49 : [Music]
30:52 : um
30:53 : i would assume you can
30:55 : get at the zeroth element of the query
30:58 : set yeah so called this q
31:00 : so this is the
31:03 : q is the question i can ask hey were you
31:07 : published
31:09 : recently
31:11 : and this is a method so i use the
31:13 : parentheses to call it
31:16 : um
31:18 : oh time zone is not defined
31:22 : i forgot to uh define time zone i need
31:25 : to import time zone
31:27 : so from
31:29 : triangle
31:32 : django
31:33 : dot utils i'll import time zone and
31:37 : we'll also need to import date time as
31:40 : well apparently
31:44 : try one more time so quit out of the
31:47 : show
31:48 : go back into it
31:52 : [Music]
31:53 : import the models
31:57 : query for the
31:58 : question there's the question and i
32:02 : were you published recently true
32:07 : beautiful
32:08 : that's what i was expecting and if i if
32:11 : i changed it
32:19 : maybe changed it to january here
32:24 : and then i saved it
32:26 : can i save it and then i do it again
32:32 : false yeah so that works
32:37 : okay um
32:38 : [Music]
32:40 : next uh oh you can also there there are
32:44 : other methods so let me show those so
32:46 : you can
32:47 : get
32:49 : a
32:49 : object by
32:52 : filtering on a
32:53 : particular column and the id is a common
32:57 : one to use for that so question dot
33:00 : objects dot get
33:02 : id equals one
33:04 : and then you would get that uh you can
33:06 : probably also filter on the any field
33:11 : maybe question text
33:13 : equals what's
33:16 : new
33:18 : no
33:21 : question
33:23 : and that i used to write
33:26 : what's new
33:29 : question text
33:31 : equals what's new oh question mark
33:34 : i forgot the question mark
33:36 : so that worked yeah
33:38 : so you can
33:40 : query based on any field of the table
33:44 : um and if if it doesn't find it then it
33:48 : will say
33:49 : it will throw an error saying like
33:52 : you'll throw an error
33:54 : that does not exist error question
33:57 : matching query does not exist
33:59 : uh that the same thing would happen if
34:02 : you create by id
34:04 : i imagine so if i curve for
34:07 : id one
34:09 : we find that one question in our
34:12 : database if we query for id number two
34:15 : and we get a does not exist
34:23 : you could also use pk as a special field
34:27 : that means the id
34:30 : although i'm sure you can change the
34:32 : primary key to something else if you
34:34 : wanted to there you probably need to
34:37 : configure the model
34:38 : differently
34:41 : you can also do this create
34:46 : oh choice set oh interesting
34:49 : so this i have a question and i actually
34:53 : have a choice set
34:57 : dot oh and these are all my choices but
35:00 : i could i could create a choice
35:04 : object
35:05 : via the question object
35:08 : by saying
35:10 : choiceset.create
35:14 : um what's new
35:17 : not much okay
35:19 : and then votes equals zero
35:23 : and then we have created a choice did it
35:26 : get into the database yet or do i have
35:28 : to save it
35:35 : it did already go into the database okay
35:41 : and i can twice create
35:44 : what's new
35:47 : my hat
35:50 : okay
35:53 : and now that went into the database as
35:55 : well cool
35:57 : and then
35:58 : this okay this is pretty nifty to have
36:01 : this choice set i mean
36:05 : um
36:07 : you could also
36:08 : uh query for the choices via the choice
36:14 : class
36:15 : choice.objects.org
36:17 : and then you have all the choice objects
36:19 : that i've created um
36:21 : in this way you query for them at a
36:23 : global level instead of having them hang
36:27 : off of this question object
36:32 : it's a very cool api you could also
36:35 : delete stuff obviously
36:38 : so like um
36:40 : maybe i'll get
36:42 : the zeroth choice
36:44 : see not much i'm gonna delete that
36:48 : you can do that and then
36:49 : if we go check in the database it's gone
36:52 : now
36:56 : okay
36:57 : now let's talk about the django admin
37:00 : um
37:01 : so django admin is um
37:05 : is a very powerful feature of django uh
37:09 : it's one of its very strong selling
37:12 : points actually
37:14 : django was written in a newsroom
37:16 : environment like django initially was
37:19 : created
37:21 : in a
37:23 : news
37:24 : publishing company
37:27 : and
37:28 : the
37:29 : basically the
37:32 : content publishers had to modify what
37:35 : would eventually get published on the
37:37 : next issue
37:38 : um
37:40 : constantly so this
37:42 : django admin allows
37:45 : non-developers to do that so
37:48 : it has a full uh
37:50 : sort of crud interface that allows you
37:52 : to edit the database
37:55 : data
37:56 : um
37:57 : which you could also do with a database
38:00 : editing gui editing tool like this
38:03 : but um
38:04 : the django admin tool
38:06 : allows you to do that and it has a bit
38:08 : of a more user-friendly user interface
38:11 : so let's see it
38:13 : so but first we need to create a super
38:15 : user
38:16 : before we can do that so let's do that
38:19 : so python manage dot py
38:21 : create super user
38:26 : um
38:27 : airport yh is my username so i'm gonna
38:30 : just use that and i'm gonna use my email
38:33 : address
38:36 : my super secret password
38:40 : okay and it has created the super user
38:42 : successfully and you can actually see
38:44 : this in the database
38:46 : all user uh that's me
38:49 : that's uh well you can't
38:52 : that's my super secret
38:54 : password hashed and this is my user
38:56 : information went into the database and
38:58 : now
39:00 : i can start the development server just
39:03 : like i did previously
39:06 : but this time i'm going to go to the
39:09 : admin
39:11 : page
39:12 : which i can instead of typing in polls
39:14 : in the address bar i can type in admin
39:19 : like that and i get this and now i can
39:21 : log in
39:23 : uh using the credential that i just
39:24 : created uh it's already been auto filled
39:27 : for me i'm gonna log in
39:29 : and now
39:31 : i have this
39:33 : pretty nice looking pretty kick-ass
39:36 : looking user interface that allows me to
39:39 : edit
39:42 : certain database tables using a very
39:45 : intuitive
39:47 : user interface so
39:49 : for example i can add a user
39:52 : um
39:54 : maybe
39:56 : that user named marty
40:04 : and now save it
40:06 : uh
40:17 : oh the password is too common okay i
40:19 : don't feel like dealing with this so but
40:21 : anyway you can you can add it
40:24 : you can edit uh
40:26 : the database table maybe it'll
40:29 : be easier
40:30 : if i show editing or question and choice
40:33 : tables which let's let's go ahead and do
40:35 : that actually
40:39 : so notice that we don't get the question
40:43 : and choice tables here but we can change
40:45 : that easily
40:47 : by
40:48 : registering our question and choice
40:50 : tables
40:52 : here is saying let's register the
40:54 : question table
40:56 : into polls slash admin dot py
40:59 : i'm going to do both of them
41:10 : okay
41:12 : so from that models
41:15 : import question and choice
41:21 : admin site
41:23 : register
41:25 : question
41:28 : and i'm gonna also register choice so
41:31 : that both of them
41:32 : come up in our admin
41:35 : site
41:37 : i don't think you even have to
41:39 : update
41:40 : you restart the server so i'm going back
41:43 : to the site and now i have questions and
41:45 : choices
41:46 : and i can add a question
41:50 : question hey
41:52 : uh
41:53 : what's for dinner
41:57 : and i just put
41:59 : today and now
42:00 : um save
42:04 : so i have another question called what's
42:06 : for dinner
42:07 : um okay
42:10 : i can also go into choices
42:13 : and add a choice and i can say what's
42:16 : for dinner and my choice is
42:18 : fried chicken
42:22 : save and add another
42:27 : lasagna
42:36 : okay so now i have a few choices in
42:38 : there
42:39 : so
42:40 : um
42:43 : yeah so this is a
42:44 : this is like a full-fledged
42:47 : crud interface
42:49 : correct standing for create
42:51 : when i say crud
42:55 : uh i mean
42:56 : create
42:58 : a retrieve
43:02 : update
43:05 : and delete
43:06 : so whereas in the ruby on rails web
43:09 : framework there's a scaffolding
43:12 : functionality to quickly
43:15 : get your
43:17 : site
43:18 : to to for any particular model to look
43:21 : like this
43:22 : in django it's
43:25 : you're you're basically
43:27 : this is
43:28 : more full featured and it exists
43:33 : in addition to customizations rather
43:36 : than in lieu of the customizations so
43:40 : okay so i think we're gonna stop there
43:43 : for part two