Add a Detail View

Let's take a look at what all we've done so far. 0:00 We have a project with an app, we have a global project wide view, our homepage, 0:01 that renders a template. 0:06 That template also uses a master layout template. 0:07 In our app we have two models and two migrations. 0:11 We have our models registered with Django's admin and 0:14 we have a view to see all of the courses that we've created. 0:17 We've come a long way. 0:19 Great job. 0:21 Now let's go see about showing the details of a single course. 0:22 So now we have two models and our admin is set up to edit both of them pretty nicely. 0:26 So let's see about adding a view for looking at a single course as a student. 0:31 Let's get over here and let's look at views. 0:36 We have a way to view all of the courses. 0:38 We get all the course names, right? 0:43 It'd be really cool. 0:45 Let's open this up, we're going to get another. 0:47 All right, so we have our admin, we have our view, we have our editor. 0:53 A lot of tabs for editing Django sometimes. 0:58 So, anyway, it'd be nice if we could just click on, like, a course name, like, Boop! 1:00 Click on Python Basics, and go see all the steps that are in that course. 1:05 Normally we call this kind of view, 1:10 when where you're drilling into just a single item, a detail view. 1:12 Because you're viewing the details of a particular item. 1:15 So we've got views.pi open, and let's create this new view. 1:19 We don't have to import anything. 1:27 Because we've already got the render. 1:28 We've already have our course model. 1:37 We've already got that stuff. 1:38 Okay. 1:40 We do need to catch the Primary Key which is the ID field by default though. 1:40 And, I know, we didn't define one. 1:45 You remember talking about that a while ago. 1:47 Django automatically creates one for us. 1:49 So we're cool. 1:51 We're good on that. 1:52 Django saved us time. 1:53 Thanks a lot Django. 1:54 So let's say course_detail, and it of course has to take the request. 1:55 And then we'll say that it's going to take a PK as well. 2:00 Now this tells Python that we're going to have two arguments to our view. 2:03 Django's going to automatically supply the request when it calls the view function, 2:08 and we will provide the PK through our URL. 2:12 But we'll worry about that in a minute, 2:16 the rest of our view is pretty straightforward. 2:18 We need to get the course with the given PK and 2:21 then render the template, so let's do that. 2:22 Course equals course.objects.get, where PK is equal to PK and 2:24 then we're going to return render the request object. 2:30 Courses slash course detail, that HTML Course is going to equal course. 2:36 Okay. 2:43 Now we didn't define a PK attribute either. 2:44 So where did PK come from? 2:48 Well, Django knows what field is our primary 2:49 key which is what PK stands for, Primary Key. 2:55 By default, it's the ID. 2:58 So, Django's like, oh, cool. 3:00 You want the primary key, you want the ID? 3:01 Great, here you go. 3:03 Let's just go to it. 3:04 So we'll deal with what happens if the course doesn't exist, 3:06 a little bit later on. 3:09 For now, though, let's just pretend that nobody's ever going to type in a bad URL. 3:10 [LAUGH] And that reminds me, we need a URL for this. 3:14 So let's go check out our URLs. 3:17 So we need to add a new line for the next URL. 3:21 And this URL is going to be really, really similar. 3:25 So we're going to do r and a quote and then we're going to catch a PK, 3:28 with a cap P there, and then we're going to do a slash d. 3:34 And there's going to be one or more of those, and that's going to end the line. 3:40 Now it's going to go to views.course_detail and that's it. 3:45 So what does this do? 3:50 This is a named group right here, and we're going to call this group PK, 3:51 that's the name of the group, is PK. 3:55 And it's going to be one or more digits that come in the URL. 3:58 That's going to go to course detail. 4:03 All right. 4:05 But, notice that we left off the chevron. 4:07 That's because our other URLs, where are they, right here. 4:11 We have this chevron here. 4:15 So the string starts with courses. 4:16 It can't start with the vk. 4:19 Just a little bit of logic there, I guess. 4:20 All right, [LAUGH] so last piece, we need a template. 4:23 So let's get our template. 4:25 So inside of our templates directory, inside of our courses directory, 4:27 we're going to create new file and we're going to call it course detail.html and 4:30 inside course detail.html we want to extend 4:36 our layout.html. 4:41 And then we want to be able to set some stuff. 4:46 So let's set block title is equal to whatever course we're looking at. 4:47 That course is title. 4:53 All right, and then we're going to have block content. 4:58 So inside block content, 5:04 we're going to do any little bit of extra HTML just to make our designers happy. 5:06 So, we're going to have an article tag, we're going to have an H2 tag, 5:12 with the course title. 5:16 And, then let's do the course description. 5:22 And then, 5:26 we should probably also print out the name for each step in our course. 5:30 Now we can do that by looping through a new. 5:34 Let's add a couple of things here first. 5:38 So we're going to do a section so 5:40 we can loop through a special new attribute. 5:43 That's called Stepset, and 5:49 Stepset is a query set. 5:54 So it's a bunch of records. 5:57 And, since it's a query set, we can query against it. 5:59 So we're going to use all to get all of them. 6:04 And notice we don't include the parenthesis when we're inside of 6:07 Django's templates. 6:10 So inside here we have each thing called step. 6:12 And we're going to print out something. 6:14 So let's do step.title and 6:19 then let's do step.description. 6:23 So, we have our article tag. 6:29 We have an H2, we have a description. 6:31 We have our section tag. 6:33 Inside here, we have an H3 and a description. 6:35 We end our section, we end our article. 6:37 Pretty simple HTML, yeah? 6:40 So let's see how it renders. 6:42 So, we can't get to it from here. 6:44 But let's go. 6:49 We know that Python Basics is number one. 6:49 And we forgot to close something. 6:52 We did. This should be endfor not endblock. 6:55 Endfor. 6:59 Refresh. 7:02 There we go. 7:03 Python Basics is the title of our course. 7:05 Learn the basics of Python. 7:07 And then What's the deal with strings is one of the steps, and 7:08 there's the description of that step. 7:10 Not too bad. 7:13 Django's ORM really helped us out there with step set attribute. 7:14 Sometimes though that ends up being a less than optimal addition to your queries. 7:18 I'll link to a couple of really handy RM functions named select related and 7:22 prefectrulated. 7:26 They're outside of the scope of this course, but they can come in really handy. 7:27 We'll definitely cover them in a later course, but check them out right now. 7:30