Exclusivity

We can use the filter method to filter records based on the value of their own 0:00 attributes, or the value of a related model's attributes. 0:04 But what if we need to filter based on a condition of the attribute, like 0:07 that it contains the characters D-O-G, or that it's a number greater than five? 0:11 We can do that with field lookups. 0:16 Let's go check them out. 0:17 I think we should make a search form and a view, like right over here. 0:20 That we can use to look for courses that are specific words or 0:25 characters in their title. 0:28 So first we need to add the form to our layout template. 0:30 Now this might seem a little weird to some of you that I'm gonna do it this way. 0:34 It's not in the new site it's in templates. 0:40 Layout. 0:44 But I promise you there's a method to this madness. 0:46 So let me add this in real quick, and then I'll talk about what we're gonna do. 0:49 So section class equals top bar right. 0:53 And then, form action. 1:00 We don't have an action just yet. 1:02 Method is, GET, by default, but it's nice to be explicit. 1:05 And type equals search. 1:16 Name equals Q and then. 1:18 And we'll say search on the button because our life form is actually. 1:33 Okay, so now, why am I doing it here? 1:39 Why am I writing the HTML and the reason is actually pretty simple? 1:42 The reason I am writing the HTML is because if I don't write 1:45 the HTML then I have to go and instantiate this form on 1:50 every view where I have to make it a template tag or something like that. 1:55 And while I can do that and it's totally cool and 1:58 fine to do that, it's not really a thing I wanna do. 2:00 I'd rather just hard code thing and be done with it. 2:06 So we're gonna do search, And 2:09 I'm just gonna go to views.search and our name will be search. 2:12 Pretty simple. 2:18 So let's go fix this with our URL will be courses:search. 2:20 All right cool. 2:28 So we have the URL, we have the template. 2:29 We need to go and create the view. 2:31 All right. 2:35 So this is gonna be very similar to our courses by teacher. 2:36 So we will do Def search, 2:40 and it's gonna take a request. 2:45 And term is gonna be equal to request.GET.get Q. 2:48 So hopefully it's there. 2:53 And then we will do courses=models.Course.objects.filter. 2:56 Title. 3:03 I don't want to do title equals though I want to title__icontains. 3:04 And then the term. 3:09 And so 3:11 up here we use the double underscore to go from one model to the next. 3:12 Right, like we're on the course model gonna look at their teacher. 3:18 The teacher is a foreign key. 3:21 Okay on that foreign key related model, there should be a field called user name. 3:22 What we're doing here is kind of similar. 3:26 We have the course model. 3:29 Go look at the title. 3:30 Title is in a foreign key, title's an actual thing. 3:31 The title should contain whatever this term is and 3:34 the i says make this case insensitive. 3:38 So if I search for the word apple, all in uppercase, and 3:41 the title has the word apple in lowercase, but with a capital a, it'll still match. 3:44 So cool. 3:50 And then we want to return render request, 3:52 courses/course list.html and 3:55 courses as courses. 4:02 All right, cool. 4:06 So let's go over here and let's refresh our page. 4:08 Nothing here by geoduck still. 4:12 And then let's search for something, so 4:14 I'm gonna search for testing, actually search for test. 4:15 Look, cool, I got one thing. 4:19 Python testing. 4:20 So that's there, let's try like OBJ. 4:21 All right I'll return a Python Java objects. 4:26 All right cool. 4:28 So let's try searching for something that shouldn't exist. 4:29 Let's try earthworm. 4:31 I don't think earthworm is in any of our courses and it's not cool. 4:32 So we could expand this a little bit further we could look for 4:37 letter sequences in our descriptions. 4:41 Or we could like make sure they I mean is I can submit A, and 4:43 that's gonna find everything everything as an A in it somewhere. 4:47 We could do it so that doesn't do that, we could do those things. 4:49 Those are going to require a little more knowledge than we already have, 4:52 at least the descriptions one will. 4:54 So we'll come back to that in a little bit. 4:56 You go ahead and do the things that are too short. 4:58 If you want. 5:00 Now what if you wanna skip records that match your query? 5:01 Instead of using filter we can use exclude and 5:04 find records that we don't want to include. 5:07 I think is a little easier to try in the shell. 5:10 So let's pop this up and I'm going to Python manage.py shell. 5:13 I'll add up a little higher with that even, all right. 5:21 And so then I had to do from courses.models 5:24 import course, and here's what I want. 5:28 I wanna do course.objects.exclude where the subject 5:32 is in Python or Java. 5:37 So I want all the courses that are not about Python or 5:41 about Java and I get a lot of stuff. 5:44 Now why did I get these one, two, three, four things? 5:48 Because those existed 5:52 before I loaded the fiction data they don't have a subject set. 5:53 But nothing else in here has that. 5:57 In fact, let's go python = 5:59 Course.objects.filter(title_icontains 'Python'). 6:01 All right? 6:11 For course in python: course.subject="Python, 6:12 course.save(). 6:19 All right, cool. 6:22 So, now if we were to rerun this thing. 6:24 And we don't get ours so cool. 6:29 Now everything works and my data is correct. 6:30 Yeah. 6:32 There are a lot more field lookups available and 6:34 we'll be using some of them during the rest of this course. 6:36 I've also put a link into the teacher's notes to the documentation about them so 6:39 be sure to check it out and play around with them by yourself. 6:42 All right. Take a little break get a drink. 6:45 Take a walk around the block and then come back for my next update video. 6:47 The next video is about updating records. 6:51