Multiple Choice and True/False Questions

When we extended our Step model, we made an abstract and 0:00 then extended it with our Text and Quiz models. 0:03 This was great, 0:06 because we didn't need another model in the database, our step table. 0:07 But I think it makes more sense to have one question table. 0:10 And then a new table for each of multiple choice questions and true false questions. 0:13 This type of inheritance, where we have more than one table in the database, 0:19 is called multi-table inheritance or MTI. 0:22 Let's take a look at this in Workspaces. 0:26 So we have our Question model, which is a very generic question. 0:28 It just has a prompt and it will have answers that are associated with it. 0:32 Even though I may not always have something specific to a certain 0:36 type of question, I wanna be able to put in multiple types of questions. 0:42 So I wanna have a multiple choice question, and 0:48 I wanna have a true false question, maybe I'd have a fill in the blank. 0:51 Yeah, I don't even know what other kinds of questions, I could have. 0:56 So I wanna be able to represent each of these in the database and 0:59 in it's own particular way. 1:02 So, let's do that. 1:04 So let's a MultipleChoiceQuestion and this is going to inherit from Question. 1:07 And now Question is not abstract. 1:10 We did not put that abstract = True inside Question's Meta. 1:14 So Question will have a table and MultipleChoiceQuestion will have a table. 1:17 And every time we look up a MultipleChoiceQuestion, 1:22 we'll work our way back to the actual question through a foreign key. 1:24 But we don't have to specify that foreign key, 1:28 Django knows there's one because this one is an abstract and this one inherits. 1:30 So let's add in shuffle_answers. 1:35 And this will be a BoleanField and the default will be False. 1:40 So by default we don't wanna shuffle our answers. 1:47 And then let's add in a TrueFalseQuestion, which is the question. 1:51 And you know what, I don't have anything special I want to do in that model. 1:57 That model's very, just plain. 2:03 You know what, I just realized I was about to 2:05 do something I told you not to do a minute ago. 2:08 Let's [LAUGH] do our migrations. 2:11 So there's our multiple choice. 2:18 And then we'll uncomment our TrueFalse and 2:19 make a new migration for TrueFalse. 2:24 And then we'll migrate. 2:28 Cool, ran both of those. 2:30 Run our server. 2:33 All right we're back up. 2:35 So now if we look at this we still just have question, and 2:39 if we were to just add a question, there's nothing special here. 2:42 So what we wanna do is we wanna go over here to admin. 2:47 So remember, we're gonna keep putting all these things in. 2:52 And we should be able to just do MultipleChoiceQuestion, 2:54 And TrueFalseQuestion. 3:03 Let's see what that gives us in the admin. 3:07 So I'm gonna add a multiple choice question. 3:09 And you can see I still get the Quiz, and I still get the Order, and 3:12 I still get the Prompt, and I still get the Shuffle answers, my new one. 3:15 I don't have to go and make a question, and 3:20 then go make a multiple choice question. 3:21 I don't have to keep going back and forth between those two. 3:23 So that's a really nice thing for the admin. 3:27 Many Django developers will warn you, appropriately, not to use MTI. 3:31 In fact, you can include me in that list. 3:35 But the caveat there is to not use it when you don't absolutely need it or 3:38 can't do it cleanly. 3:42 Our approach here, though, is a good, safe approach. 3:43 Okay, I think our models are in good shape. 3:47 So let's look at the major type of Django form known as a model form. 3:49