WEBVTT 1 00:00:00.290 --> 00:00:01.680 Hi guys and welcome back. 2 00:00:01.680 --> 00:00:03.350 In this video, we're going to do something similar 3 00:00:03.350 --> 00:00:05.000 to what we did in the last one, 4 00:00:05.000 --> 00:00:07.890 but for cursors in our database.py. 5 00:00:07.890 --> 00:00:09.780 Because we've got a bit of duplication here. 6 00:00:09.780 --> 00:00:11.183 So let's get to it. 7 00:00:12.360 --> 00:00:15.870 Every function here has these two contextmanagers. 8 00:00:15.870 --> 00:00:19.100 We could make it into one contextmanager if we want. 9 00:00:19.100 --> 00:00:20.380 So how are we gonna do that? 10 00:00:20.380 --> 00:00:22.820 Is first of all, by creating the contextmanager 11 00:00:22.820 --> 00:00:25.470 that I'm gonna call, get cursor. 12 00:00:25.470 --> 00:00:27.700 And this one is gonna take in a connection. 13 00:00:27.700 --> 00:00:28.533 And what it's gonna do, 14 00:00:28.533 --> 00:00:30.910 is gonna do with connection 15 00:00:30.910 --> 00:00:34.420 and then with connection.cursor as cursor, 16 00:00:34.420 --> 00:00:36.780 is gonna yield the cursor. 17 00:00:36.780 --> 00:00:40.530 This is gonna get decorated with the @contextmanager 18 00:00:40.530 --> 00:00:42.380 as well, and we have to import it. 19 00:00:42.380 --> 00:00:43.360 So we're doing that. 20 00:00:43.360 --> 00:00:46.050 Notice that all that does is from contextlib 21 00:00:46.050 --> 00:00:48.920 input contextmanager at the top. 22 00:00:48.920 --> 00:00:51.720 Now, what we can do is instead of doing all of this, 23 00:00:51.720 --> 00:00:56.720 we can do with get cursor of connection as cursor, 24 00:00:57.360 --> 00:00:59.413 and that does that. 25 00:01:00.770 --> 00:01:02.860 Totally up to you whether you wanna do this or not, 26 00:01:02.860 --> 00:01:04.830 we don't need a try finally here 27 00:01:04.830 --> 00:01:06.320 because these contextmanagers 28 00:01:06.320 --> 00:01:08.260 already clean up after themselves. 29 00:01:08.260 --> 00:01:10.180 So just yielding the cursor means 30 00:01:10.180 --> 00:01:12.100 that we're gonna get to here with the cursor, 31 00:01:12.100 --> 00:01:14.200 return it here so we can run this 32 00:01:14.200 --> 00:01:15.940 and then it's gonna go back up here 33 00:01:15.940 --> 00:01:18.660 and close these contextmanagers as well. 34 00:01:18.660 --> 00:01:20.810 So if you wanna do this, for simplification, 35 00:01:20.810 --> 00:01:22.760 then by all means, go for it. 36 00:01:22.760 --> 00:01:25.943 I'm gonna apply this to all my other functions as well. 37 00:01:37.620 --> 00:01:40.300 So I've gone ahead and applied get cursor 38 00:01:40.300 --> 00:01:42.080 to all of these functions. 39 00:01:42.080 --> 00:01:43.770 One of the great things about this 40 00:01:43.770 --> 00:01:45.700 is you don't necessarily 41 00:01:45.700 --> 00:01:49.160 have to put get cursor here in database.py. 42 00:01:49.160 --> 00:01:53.980 You could put get cursor into the connection pool file here, 43 00:01:53.980 --> 00:01:55.430 instead of get connection, 44 00:01:55.430 --> 00:01:58.840 then all your functions here or your methods 45 00:01:58.840 --> 00:02:03.330 could use a cursor directly passing it into database.py. 46 00:02:03.330 --> 00:02:04.163 It's up to you 47 00:02:04.163 --> 00:02:06.610 whether you wanna be passing cursors or connections. 48 00:02:06.610 --> 00:02:08.520 If you only have one connection 49 00:02:08.520 --> 00:02:10.500 that you create at the start of the application, 50 00:02:10.500 --> 00:02:14.370 you could then simply use cursors every time, 51 00:02:14.370 --> 00:02:17.080 and in a single connection application 52 00:02:17.080 --> 00:02:18.750 that doesn't use connection pooling. 53 00:02:18.750 --> 00:02:21.020 That is probably going to be faster. 54 00:02:21.020 --> 00:02:23.530 So it's up to you whether you wanna do that, 55 00:02:23.530 --> 00:02:26.840 but here we're worrying more about future scalability 56 00:02:26.840 --> 00:02:28.880 by using connection pooling. 57 00:02:28.880 --> 00:02:31.450 If you wanted to use a single connection 58 00:02:31.450 --> 00:02:33.360 and not worry about multiple connections, 59 00:02:33.360 --> 00:02:36.240 then you could put this inside connection pool 60 00:02:36.240 --> 00:02:39.410 or rather maybe cursors or something like that, 61 00:02:39.410 --> 00:02:40.900 this file could be called, 62 00:02:40.900 --> 00:02:43.800 and be passing cursors around instead of connections. 63 00:02:43.800 --> 00:02:45.740 But the aim of these two changes 64 00:02:45.740 --> 00:02:48.690 were to teach you about simplifying your code 65 00:02:48.690 --> 00:02:51.500 using these contextmanagers and how you can do that. 66 00:02:51.500 --> 00:02:53.080 So hopefully this has been useful. 67 00:02:53.080 --> 00:02:54.190 I hope you've learned something. 68 00:02:54.190 --> 00:02:57.090 Thank you for watching and I'll see you in the next video.