WEBVTT 00:01.300 --> 00:01.900 Okay. 00:01.900 --> 00:10.420 In this video we will be talking about filter options and what are the filter options in our model file? 00:10.420 --> 00:12.040 I can actually remove that comment. 00:12.040 --> 00:12.970 And now. 00:14.010 --> 00:19.690 So we have our model here, which is a book, and we have our one field. 00:19.710 --> 00:22.620 So the field options is everything. 00:22.620 --> 00:28.730 What we pass in that parenthesis at the moment we have max length, which is 36. 00:28.740 --> 00:37.500 I can remove it from now here and then I can pass some other parameters into that field and that all 00:37.740 --> 00:40.260 parameters are field options. 00:40.260 --> 00:42.320 So what options do we have? 00:42.330 --> 00:46.680 So let's go to the official Django documentation. 00:46.680 --> 00:56.730 If we go here we are on the page docs Django Project.com English to point to reference model field and 00:56.730 --> 00:58.650 we have model field reference. 00:58.650 --> 01:05.520 The first section is the field options and we have a bunch of different options that we can pass to 01:05.520 --> 01:12.150 our field and all of them are listed here and I will go through a few of them and I will show you the 01:12.150 --> 01:17.280 most popular and the one that we will use in our tutorial. 01:17.280 --> 01:24.060 So if you would like to know more about them, there is a good read about each of them here. 01:24.060 --> 01:29.850 So if you need something special, you can also refer to this list and find something that will be useful 01:29.850 --> 01:30.660 for you. 01:30.840 --> 01:37.080 Okay, so let's go back to our models here and let's try different options. 01:37.080 --> 01:46.950 So first, what we can pass here is we can pass null and then Null accepts the arguments of true or 01:46.950 --> 01:47.610 false. 01:48.480 --> 01:49.590 So it's a boolean. 01:50.760 --> 01:51.450 What does it mean? 01:51.450 --> 01:52.080 A null. 01:52.080 --> 01:53.130 So null. 01:53.160 --> 02:01.920 Basically, we are telling Django that if this field is empty then we should store null in the database. 02:01.920 --> 02:07.650 So this is purely a database field and it's not going to impact our validation. 02:07.650 --> 02:10.920 We have another field which is called blank. 02:12.750 --> 02:16.930 And then we also can pass true or false into it. 02:16.930 --> 02:20.680 Blank is a validation for our field. 02:20.680 --> 02:29.050 It means that if we have blank true means that we allow this field the title to be blank, which is 02:29.050 --> 02:29.770 empty. 02:30.040 --> 02:37.570 So if I will have blank true, we can create new book with no title if we'll have it to false. 02:38.470 --> 02:45.100 That means this title is required and we can't pass it really as empty. 02:45.100 --> 02:50.140 So I will leave it blank false here, which is by default like that. 02:50.140 --> 02:52.840 So another option what we can have. 02:52.840 --> 02:56.200 I will leave the null as well just for future references. 02:56.200 --> 02:57.130 So null. 02:57.130 --> 03:03.520 I will say true, but it doesn't really matter that much because if we have blank false and we don't 03:03.520 --> 03:07.900 allow this to be blank, then there is no way that field will be true. 03:07.900 --> 03:14.650 So I will leave it for reference here that we can use it, but in fact this will never happen together. 03:14.680 --> 03:19.300 Another option that I would like to show you is unique like that. 03:19.300 --> 03:22.510 And we also can pass true or false unique. 03:22.510 --> 03:31.030 I will pass it as true because unique means that if we will have multiple records in that table, each 03:31.030 --> 03:33.700 of these the title need to be unique. 03:33.700 --> 03:39.070 So as you remember from previous video, I add Hobbit book into our database. 03:39.070 --> 03:45.430 And if I would like to add another book with the same title, it will be prohibited. 03:45.760 --> 03:53.020 So you can't have two books with the same title in the database if you have that unique true. 03:53.050 --> 03:59.200 So basically you might have more than one field here and you can decide which one will be unique in 03:59.200 --> 04:00.250 our database. 04:01.260 --> 04:04.290 Another option will be default. 04:06.290 --> 04:06.910 Like that. 04:06.910 --> 04:09.310 And then this depends on the type. 04:09.400 --> 04:12.010 What we have here, it's a char field. 04:12.010 --> 04:14.560 That means it's a simple text or a string. 04:14.560 --> 04:19.840 So if we'd like to store a string, then we need to provide a default one. 04:19.840 --> 04:27.490 If we would like to have a default as empty here, then if we want to provide any data to this field, 04:27.520 --> 04:30.190 then the by default it will be stored like this. 04:30.190 --> 04:32.920 So basically this makes no sense with a null. 04:32.950 --> 04:33.460 True. 04:33.490 --> 04:38.080 Because if you have a null true then it will never hit this null. 04:38.110 --> 04:40.360 True because the default will be empty. 04:40.360 --> 04:43.570 And also blank is false here. 04:43.570 --> 04:45.310 That means it will be required. 04:45.310 --> 04:50.680 So the default will never will be triggered with a empty string here. 04:51.040 --> 04:55.560 So you need to kind of pick which one you would like to use it. 04:55.570 --> 05:01.180 I just put it all of them here just for reference and we'll remove it later on. 05:01.180 --> 05:09.140 But pay attention what you are putting here because that will rule the way you create your new records 05:09.140 --> 05:10.190 in a database. 05:10.850 --> 05:13.250 So another option I will go to the new line. 05:13.250 --> 05:15.140 Here is choices. 05:16.560 --> 05:23.000 And then we can decide what is acceptable values for this field. 05:23.010 --> 05:30.270 So what we can do is we can decide a set of different values that will be accepted and not accept of 05:30.270 --> 05:34.260 that values will be in this field acceptable. 05:34.260 --> 05:37.710 So let's create a new variable here and we call it. 05:39.630 --> 05:40.410 Like that. 05:40.860 --> 05:42.150 And that's our constant. 05:42.150 --> 05:49.460 So we put it all uppercase here, and then we'll open parentheses and inside we'll create a set. 05:49.470 --> 05:52.560 So it will be pair value. 05:52.560 --> 06:01.110 So let's do for example, HB like Hobbit, and then we might have another one. 06:13.740 --> 06:15.570 Lord of the Ring like that. 06:15.570 --> 06:21.870 So basically we have here a tuple which is a set of value pairs. 06:21.870 --> 06:26.940 So we have HP and Hobbit and then Lord and Lord of the Rings. 06:26.940 --> 06:35.910 So what we I can do here is I can pick these choices books and the only values that will be accepted 06:35.910 --> 06:39.960 in our books will be this value specified here. 06:40.290 --> 06:47.220 So there is no way we can put something else except of these values there. 06:47.610 --> 06:50.430 Maybe for a books and a title. 06:50.430 --> 06:56.340 It makes no sense to have choices like this, but we might have something like a, I don't know, a 06:56.340 --> 07:03.240 stars or something based on the numbers, and you might accept only certain things. 07:03.240 --> 07:10.620 Or for example, if you have a status like a maybe a order status, and then you might have something 07:10.620 --> 07:15.370 like let's say you can have it zero and then it will be. 07:18.180 --> 07:20.460 And then you might have another status. 07:32.710 --> 07:36.340 And then we can have, for example, like that. 07:38.130 --> 07:40.490 So we might have a different status. 07:40.500 --> 07:42.600 Let's call it status. 07:44.440 --> 07:52.000 And then we might have it here for different let's say we are having our store and then we have a status 07:52.000 --> 07:53.770 status for orders. 07:53.770 --> 08:01.660 So we might accept only zero 1 or 2 in our database and zero will represent unknown status and then 08:01.660 --> 08:06.160 one will be processed and the second one will be paid or wherever you will have it here. 08:06.160 --> 08:15.880 But the the key here is that choices will restrict only to these values from the array that we set up 08:15.880 --> 08:16.720 in here. 08:16.720 --> 08:24.010 So that's sometimes is very handy in our case, in case of title as we have it here, this makes no 08:24.010 --> 08:29.290 sense because we like to us add as many book titles as we want. 08:29.290 --> 08:32.710 And in our case, what makes sense is. 08:33.970 --> 08:36.100 We can remove the default one. 08:36.130 --> 08:38.140 We can also remove the choices. 08:38.170 --> 08:45.010 We can leave unique as true because we don't want to have multiple books with the same title in our 08:45.010 --> 08:45.850 database. 08:45.850 --> 08:48.220 And then we'll do blank False. 08:48.670 --> 08:57.460 That means it will be required field and it needs to be unique so I can remove this and whatever I change 08:57.460 --> 08:58.390 in this. 08:59.500 --> 09:00.260 Field. 09:00.370 --> 09:02.200 I will save the changes here. 09:02.200 --> 09:07.960 I can open the terminal and I can do Python three Manage.py. 09:09.240 --> 09:11.580 Make migrations. 09:14.300 --> 09:17.710 And you can see here, I forgot to add the max length. 09:17.720 --> 09:20.310 The char field must define the max length. 09:20.340 --> 09:23.720 I had it before, but I remove it to show you the other attributes. 09:23.720 --> 09:29.000 So we will come back to this and we'll do 36 as we had it there. 09:29.000 --> 09:32.870 So Max, length of this char field will be 36. 09:32.870 --> 09:35.630 And then we decided blank, true and unique. 09:35.630 --> 09:36.110 True. 09:36.110 --> 09:42.530 So I will save this now and then I will do make migrations and you can see Alter Fields title on the 09:42.530 --> 09:42.860 book. 09:42.860 --> 09:50.120 So whatever we do some changes in our field, we need to register that and set the database to accept 09:50.120 --> 09:51.500 these values here. 09:51.710 --> 09:59.450 So if this is required, required a unique the database will be set up for this fields like that. 09:59.630 --> 10:07.340 So once we have this, you can see migrations, we have another file and this file is basically changing 10:07.340 --> 10:09.800 this with some setup. 10:09.800 --> 10:13.680 So we'll close it, but it's not hitting the database yet. 10:13.680 --> 10:19.530 So as you remember to apply to the database, we need to use command migrate. 10:21.380 --> 10:25.340 And we have our migration applied to this. 10:25.370 --> 10:29.120 We also have some admin and authorization changes here. 10:29.120 --> 10:35.740 We saw a prompt from the Django about those that hasn't been applied yet and now they have been applied 10:35.750 --> 10:38.090 all the missing before migrations. 10:38.090 --> 10:40.910 And also the last one is Demo 002. 10:40.940 --> 10:44.180 This is the changes we just made on this field. 10:44.360 --> 10:50.390 In the next video, I will show you what kind of different field types we have.