WEBVTT 1 00:00:00.000 --> 00:00:02.560 Now that we've got the poll class, 2 00:00:02.560 --> 00:00:04.770 we're gonna go ahead and write the option class. 3 00:00:04.770 --> 00:00:07.270 So I'll open up the project, right click in here, 4 00:00:07.270 --> 00:00:11.450 create a new option.py file, and then close that up. 5 00:00:11.450 --> 00:00:13.930 And now we can get started with the option class. 6 00:00:13.930 --> 00:00:16.810 It's going to be very similar to the poll class, 7 00:00:16.810 --> 00:00:18.450 except it's gonna deal with the data 8 00:00:18.450 --> 00:00:20.170 that an option deals with. 9 00:00:20.170 --> 00:00:22.637 So here I'm gonna have written the initial code. 10 00:00:22.637 --> 00:00:25.020 We've got the list import, the database import, 11 00:00:25.020 --> 00:00:27.560 I've actually imported the createConnection function 12 00:00:27.560 --> 00:00:29.270 from the connections.py file. 13 00:00:29.270 --> 00:00:30.740 That doesn't exist yet, but we're gonna add it 14 00:00:30.740 --> 00:00:31.710 in just a moment. 15 00:00:31.710 --> 00:00:33.600 And then I've done the initial set up 16 00:00:33.600 --> 00:00:35.240 for the option class. 17 00:00:35.240 --> 00:00:37.950 An option takes in the text, the poll ID, 18 00:00:37.950 --> 00:00:40.370 and it has an ID, then just sets them there, 19 00:00:40.370 --> 00:00:43.530 and the repr() method returns the option text 20 00:00:43.530 --> 00:00:46.960 that we can use to recreate an option object. 21 00:00:46.960 --> 00:00:49.160 We're gonna need a save method as well, 22 00:00:49.160 --> 00:00:50.570 there's again creates the connection, 23 00:00:50.570 --> 00:00:51.980 calls database .option, 24 00:00:51.980 --> 00:00:53.200 which doesn't exist at the moment, 25 00:00:53.200 --> 00:00:55.960 but that just inserts a row into the database, 26 00:00:55.960 --> 00:01:00.280 and then sets the self ID to be the option returned. 27 00:01:00.280 --> 00:01:02.030 We're gonna add a get method, 28 00:01:02.030 --> 00:01:04.240 so that we can pass in an option ID, 29 00:01:04.240 --> 00:01:06.000 and it returns and option object. 30 00:01:06.000 --> 00:01:08.120 For example, if we have to find a specific option 31 00:01:08.120 --> 00:01:10.610 in the database, and then we also need 32 00:01:10.610 --> 00:01:12.690 a couple of methods to deal with voting. 33 00:01:12.690 --> 00:01:14.560 So I'm gonna add the vote method, 34 00:01:14.560 --> 00:01:16.720 that takes in a username and is gonna cast 35 00:01:16.720 --> 00:01:19.010 a vote for that username. 36 00:01:19.010 --> 00:01:20.719 So all we have to do here is again 37 00:01:20.719 --> 00:01:23.730 create the connection, then we're gonna 38 00:01:23.730 --> 00:01:26.940 do database@poll_vote, pass that connection in, 39 00:01:26.940 --> 00:01:30.875 the username, and self.ID 40 00:01:30.875 --> 00:01:34.370 and this already exists so all we're using here is the stuff 41 00:01:34.370 --> 00:01:36.578 that is already in our database.py file 42 00:01:36.578 --> 00:01:39.760 and then we do connection.close. 43 00:01:39.760 --> 00:01:42.305 Finally, I'm gonna add a property decorator 44 00:01:42.305 --> 00:01:46.850 for the votes, and that is going to return a list 45 00:01:46.850 --> 00:01:48.940 of database.vote. 46 00:01:48.940 --> 00:01:51.803 What this is gonna do is again create the connection, 47 00:01:53.490 --> 00:01:57.840 get the votes with the database.get_votes_for_option, 48 00:01:57.840 --> 00:01:58.820 which it doesn't exist yet, 49 00:01:58.820 --> 00:02:00.320 but it's gonna in a moment, 50 00:02:00.320 --> 00:02:02.370 and pass in the ID of this option. 51 00:02:02.370 --> 00:02:04.220 That's what we're gonna use to go into the database 52 00:02:04.220 --> 00:02:05.660 and fetch those votes. 53 00:02:05.660 --> 00:02:07.590 Then we'll close, 54 00:02:07.590 --> 00:02:08.970 and we're actually going to return 55 00:02:08.970 --> 00:02:11.440 those votes which again is a list of tuples, 56 00:02:11.440 --> 00:02:13.690 it's not a list of objects anymore 57 00:02:13.690 --> 00:02:15.360 because we've decided not to create 58 00:02:15.360 --> 00:02:17.540 a model class for votes. 59 00:02:17.540 --> 00:02:18.830 Let's open up our project 60 00:02:18.830 --> 00:02:21.260 and we're gonna create a new Python file 61 00:02:21.260 --> 00:02:23.546 inside there beside @.py, in database.py 62 00:02:23.546 --> 00:02:26.370 I'm gonna call it connections.py 63 00:02:26.370 --> 00:02:29.159 and all this is gonna have is a very simple function 64 00:02:29.159 --> 00:02:31.480 to create a connection. 65 00:02:31.480 --> 00:02:35.380 This we have to import from both poll.py and option.py. 66 00:02:35.380 --> 00:02:37.230 So I'm going to go ahead and do that. 67 00:02:38.971 --> 00:02:41.550 You can see that PyCharm is complaining from this import, 68 00:02:41.550 --> 00:02:44.630 that's because we have to do models.option there. 69 00:02:44.630 --> 00:02:46.580 So up to now, we've got everything 70 00:02:46.580 --> 00:02:49.370 except the database.py changes. 71 00:02:49.370 --> 00:02:51.028 Something important to note, 72 00:02:51.028 --> 00:02:54.740 when we swap out from using the database 73 00:02:54.740 --> 00:02:57.490 directly in our .py and now we're gonna 74 00:02:57.490 --> 00:02:59.146 change all this to use the models, 75 00:02:59.146 --> 00:03:02.670 is that the models are usually only concerned 76 00:03:02.670 --> 00:03:05.860 with themselves and the data they can 77 00:03:05.860 --> 00:03:08.530 put into the database and how they can use the data 78 00:03:08.530 --> 00:03:11.340 from the database to affect themselves. 79 00:03:11.340 --> 00:03:14.470 That greatly simplifies the thinking 80 00:03:14.470 --> 00:03:16.649 for us as developers around these models, 81 00:03:16.649 --> 00:03:19.760 but it can limit us when it comes to, 82 00:03:19.760 --> 00:03:23.330 you know, using the database for its maximum efficiency. 83 00:03:23.330 --> 00:03:25.580 That's why, now you're going to see 84 00:03:25.580 --> 00:03:27.670 in database.py, we've got a lot of stuff 85 00:03:27.670 --> 00:03:30.270 that simply deals with a single table. 86 00:03:30.270 --> 00:03:34.270 We no longer are gonna have many joins, for example. 87 00:03:34.270 --> 00:03:37.310 Database.create_poll just affects the polls table. 88 00:03:37.310 --> 00:03:39.425 Database.get_poll_options just get options 89 00:03:39.425 --> 00:03:40.850 from the options table. 90 00:03:40.850 --> 00:03:44.870 Database.get_poll just uses a polls table, and so on. 91 00:03:44.870 --> 00:03:46.544 Similarly in the options table, 92 00:03:46.544 --> 00:03:48.620 it's very much the same stuff. 93 00:03:48.620 --> 00:03:51.232 Database.add_option just adds to the options table. 94 00:03:51.232 --> 00:03:52.760 Get_option gets from the options table. 95 00:03:52.760 --> 00:03:55.860 Get_votes_for_option just affects the votes table. 96 00:03:55.860 --> 00:03:59.300 You can see that there's not that many joins going on. 97 00:03:59.300 --> 00:04:02.100 So, that is the trade-off that we make 98 00:04:02.100 --> 00:04:03.940 when we use this models approach. 99 00:04:03.940 --> 00:04:06.288 We lose power in the database side, 100 00:04:06.288 --> 00:04:09.883 but we gain in maintainability of our code. 101 00:04:10.780 --> 00:04:14.280 Let's start working on database.py in the next video. 102 00:04:14.280 --> 00:04:15.230 I'll see you there.