WEBVTT 00:00:00.180 --> 00:00:01.580 Hi guys and welcome back. 00:00:01.580 --> 00:00:03.490 In this video, we're going to learn about 00:00:03.490 --> 00:00:07.380 psycopg2 and psycopg2-binary. 00:00:07.380 --> 00:00:10.850 These are the two releases of the psycopg2 library 00:00:10.850 --> 00:00:13.330 that we're going to use to interact with Postgres 00:00:13.330 --> 00:00:15.330 from within Python. 00:00:15.330 --> 00:00:19.750 The what SQLite3 is for SQLite, psycopg2 is for Postgres. 00:00:19.750 --> 00:00:21.500 It's essentially a Python library 00:00:21.500 --> 00:00:23.430 that allows us to interact with the database 00:00:23.430 --> 00:00:24.510 in an easy way. 00:00:24.510 --> 00:00:27.140 SQLite3 is simpler than psycopg2, 00:00:27.140 --> 00:00:29.170 because SQLite is simpler than PostgreS. 00:00:29.170 --> 00:00:33.320 There's simply more things that we can do with psycopg2, 00:00:33.320 --> 00:00:35.500 but many things will remain similar. 00:00:35.500 --> 00:00:39.730 However, there's an initial hurdle when installing psygopg2. 00:00:39.730 --> 00:00:41.830 Unfortunately this is a very unfortunate hurdle. 00:00:41.830 --> 00:00:43.301 Something that puts off a lot of people 00:00:43.301 --> 00:00:46.200 and that's that there's two psycopg2's. 00:00:46.200 --> 00:00:49.540 There's psycopg2 and psycopg2-binary 00:00:49.540 --> 00:00:51.410 and lot of people get confused 00:00:51.410 --> 00:00:52.950 over which one to install. 00:00:52.950 --> 00:00:54.780 A lot of people have trouble installing them. 00:00:54.780 --> 00:00:56.430 So in this video, we just wanted to tell you 00:00:56.430 --> 00:00:58.250 a little bit about the differences 00:00:58.250 --> 00:01:00.560 and also which one you should install. 00:01:00.560 --> 00:01:02.650 So, for most people, 00:01:02.650 --> 00:01:05.070 especially if you're new to software development 00:01:05.070 --> 00:01:06.320 or you're only just starting, 00:01:06.320 --> 00:01:09.120 of if you're using a Windows computer, 00:01:09.120 --> 00:01:12.890 you should use psycopg2-binary. 00:01:12.910 --> 00:01:14.270 They are essentially identical, 00:01:14.270 --> 00:01:17.070 however, when you're using psycopg2-binary, 00:01:17.070 --> 00:01:19.050 you can run into some trouble later on 00:01:19.050 --> 00:01:21.080 when you're doing some really advanced stuff. 00:01:21.080 --> 00:01:22.940 Never install both. 00:01:22.940 --> 00:01:24.770 So only install one of them. 00:01:24.770 --> 00:01:27.390 If you install, say psycopg2 00:01:27.390 --> 00:01:28.790 and then you find an error 00:01:28.790 --> 00:01:31.370 and then you try to install psycopg2-binary, 00:01:31.370 --> 00:01:33.170 make sure to remove, 00:01:33.170 --> 00:01:36.390 completely uninstall psycopg2 first. 00:01:36.390 --> 00:01:39.560 But again, I recommend installing psycopg2-binary 00:01:39.560 --> 00:01:42.030 if you are slightly newer to software development 00:01:42.030 --> 00:01:43.600 or if you're only just starting. 00:01:43.600 --> 00:01:45.100 So what are the differences? 00:01:45.100 --> 00:01:47.910 Well, the main difference is that you need to build psycopg2 00:01:47.910 --> 00:01:50.030 and that means you need a lot of other programmes 00:01:50.030 --> 00:01:50.940 to make it work, 00:01:50.940 --> 00:01:52.640 because when you install psycopg2 00:01:52.640 --> 00:01:56.040 what you get is the source code of psycopg2. 00:01:56.040 --> 00:01:59.070 And that code, in order to actually make it work, 00:01:59.070 --> 00:02:01.550 needs a lot of stuff from PostgreS 00:02:01.550 --> 00:02:02.680 and from a few other programmes 00:02:02.680 --> 00:02:05.330 in order to actually, you know, build. 00:02:05.330 --> 00:02:08.490 And so that means it's a little bit more complicated to do. 00:02:08.490 --> 00:02:09.570 You can run into some errors, 00:02:09.570 --> 00:02:11.960 especially if you have any programmes missing 00:02:11.960 --> 00:02:14.500 and also sometimes psycopg2 00:02:14.500 --> 00:02:17.010 won't know where your programmes are 00:02:17.010 --> 00:02:18.850 and you have to tell it where they are. 00:02:18.850 --> 00:02:21.758 And all of those things add to some complication. 00:02:21.758 --> 00:02:24.540 Psycopg2-binary should just work. 00:02:24.540 --> 00:02:26.660 But again, like I mentioned when we do some really advanced 00:02:26.660 --> 00:02:29.140 and specialised things, it can have some trouble, 00:02:29.140 --> 00:02:31.540 but we're not gonna get to those things in this course. 00:02:31.540 --> 00:02:33.080 You don't have to worry about that. 00:02:33.080 --> 00:02:36.670 And also, we normally deploy databases to a server 00:02:36.670 --> 00:02:37.503 on the internet, 00:02:37.503 --> 00:02:39.980 we will learn more about what that means later on. 00:02:39.980 --> 00:02:41.180 And when you do that, 00:02:41.180 --> 00:02:43.560 you'll be able to build psycopg2 without trouble. 00:02:43.560 --> 00:02:45.540 I also left many references for you to read 00:02:45.540 --> 00:02:46.610 if you're interested. 00:02:46.610 --> 00:02:47.770 They can be a bit technical, 00:02:47.770 --> 00:02:49.570 but again, if you want to learn more about 00:02:49.570 --> 00:02:51.980 why I'm recommending psycopg2-binary 00:02:51.980 --> 00:02:53.830 and why there's two and so on, 00:02:53.830 --> 00:02:55.290 then you can read those. 00:02:55.290 --> 00:02:57.070 So to install psycopg2-binary, 00:02:57.070 --> 00:02:58.760 I'm gonna show you how just now, 00:02:58.760 --> 00:03:00.520 but essentially, you just find it in PyCharm 00:03:00.520 --> 00:03:02.050 or you type PIPinstall 00:03:02.050 --> 00:03:03.440 and then it'll work 00:03:03.440 --> 00:03:06.860 but you do need to upgrade PIP and Setup Tools first. 00:03:06.860 --> 00:03:11.820 And you also need Python2.7 or Python 3.4 or greater. 00:03:11.820 --> 00:03:12.960 As with the rest of this course, 00:03:12.960 --> 00:03:15.770 we're gonna use the latest version of Python. 00:03:15.770 --> 00:03:17.120 All right, let's get to it. 00:03:18.630 --> 00:03:19.820 All right, so like I mentioned, 00:03:19.820 --> 00:03:21.770 since we're now using PostgreSQL, 00:03:21.770 --> 00:03:23.290 and we're gonna start building larger 00:03:23.290 --> 00:03:24.910 and more complicated projects, 00:03:24.910 --> 00:03:26.650 we're gonna begin using PyCharm 00:03:26.650 --> 00:03:29.300 and virtual environments to manage our projects 00:03:29.300 --> 00:03:30.520 a bit better. 00:03:30.520 --> 00:03:33.020 If you don't know how to get PyCharm or what it is, 00:03:33.020 --> 00:03:35.120 or you don't know about virtual environments 00:03:35.120 --> 00:03:36.110 and what they are, 00:03:36.110 --> 00:03:37.180 I've left a couple of links 00:03:37.180 --> 00:03:39.230 in the resources section of this lecture, 00:03:39.230 --> 00:03:40.870 for you to read. 00:03:40.870 --> 00:03:44.020 We start off by creating a new project in PyCharm, 00:03:44.020 --> 00:03:45.470 and what we wanna do here 00:03:45.470 --> 00:03:47.470 is we wanna make sure to find a folder 00:03:47.470 --> 00:03:49.840 where we wanna put our entire project. 00:03:49.840 --> 00:03:51.980 And then, just at the end of it, 00:03:51.980 --> 00:03:53.410 add the name of our project, 00:03:53.410 --> 00:03:55.100 for example, movies. 00:03:55.100 --> 00:03:56.600 What PyCharm is gonna do, 00:03:56.600 --> 00:03:58.690 you need to make sure that the movies folder 00:03:58.690 --> 00:04:00.290 doesn't exist already. 00:04:00.290 --> 00:04:02.270 What PyCharm is gonna do is it's gonna create 00:04:02.270 --> 00:04:05.560 the movies folder inside this folder 00:04:05.560 --> 00:04:08.380 and it's gonna put the PyCharm project files in there. 00:04:08.380 --> 00:04:11.380 If the file already exists, then PyCharm is gonna complain. 00:04:11.380 --> 00:04:13.690 Now, for the project interpreter, 00:04:13.690 --> 00:04:17.097 we're gonna click on New Interpreter, using Virtualenv, 00:04:17.097 --> 00:04:19.160 then we're gonna leave the location as the default, 00:04:19.160 --> 00:04:21.420 pretty much and the base interpreter, 00:04:21.420 --> 00:04:23.430 we're gonna select Python3.8 00:04:23.430 --> 00:04:25.380 of if you're using a different Python version, 00:04:25.380 --> 00:04:27.780 then the Python version that you want to use. 00:04:27.780 --> 00:04:30.640 I'm gonna use 3.8 because we wanna use the latest version 00:04:30.640 --> 00:04:32.700 of Python in this course. 00:04:32.700 --> 00:04:34.670 Now, when we create a new virtual environment, 00:04:34.670 --> 00:04:36.250 what that's gonna do, essentially, 00:04:36.250 --> 00:04:38.590 is copy Python into this folder 00:04:38.590 --> 00:04:43.380 and give us a new version of Python using Python3.8 00:04:43.380 --> 00:04:45.340 that is a copy of the existing one. 00:04:45.340 --> 00:04:50.070 But it's gonna allow us to install libraries in here 00:04:50.070 --> 00:04:53.220 that don't affect or are not shared with 00:04:53.220 --> 00:04:56.410 projects that run on the base interpreter. 00:04:56.410 --> 00:04:57.290 What happens eventually, 00:04:57.290 --> 00:04:59.480 is that you can have a lot of different virtual environments 00:04:59.480 --> 00:05:02.400 each one with its own set of libraries installed 00:05:02.400 --> 00:05:04.330 that don't conflict with one another. 00:05:04.330 --> 00:05:06.630 For example, if two projects wanted to use, 00:05:06.630 --> 00:05:08.800 you know, different versions of the same library 00:05:08.800 --> 00:05:10.480 and things like that. 00:05:10.480 --> 00:05:11.900 All right, so let's click created 00:05:11.900 --> 00:05:14.940 and then we will land up with our project created, 00:05:14.940 --> 00:05:17.450 PyCharm also likes to give us tips of the day and so forth. 00:05:17.450 --> 00:05:20.060 You can read them to learn how to use PyCharm a bit better. 00:05:20.060 --> 00:05:21.940 It's all well and good. 00:05:21.940 --> 00:05:24.260 Now once we've got that, 00:05:24.260 --> 00:05:27.530 we want to go ahead and update PIP. 00:05:27.530 --> 00:05:31.390 PIP is used to install Python packages or libraries, 00:05:31.390 --> 00:05:32.780 so we want to update it. 00:05:32.780 --> 00:05:34.880 There are two ways of doing this 00:05:34.880 --> 00:05:37.270 and one way is probably gonna be faster 00:05:37.270 --> 00:05:38.660 and easier for you, 00:05:38.660 --> 00:05:41.350 and that is if you go over to the settings. 00:05:41.350 --> 00:05:43.010 Sorry, I went a bit quickly there. 00:05:43.010 --> 00:05:44.400 To the settings here in PyCharm, 00:05:44.400 --> 00:05:46.810 it's called Preferences on Mac. 00:05:46.810 --> 00:05:50.620 Then find the project, project interpreter, 00:05:50.620 --> 00:05:51.993 double click on PIP, 00:05:52.880 --> 00:05:54.720 specify the version 00:05:54.720 --> 00:05:56.910 and make sure to match the number here 00:05:56.910 --> 00:05:58.830 with the one up there. 00:05:58.830 --> 00:06:00.940 And then press install. 00:06:00.940 --> 00:06:03.730 However, I've got a bit of a weird installation here 00:06:03.730 --> 00:06:04.563 on my computer, 00:06:04.563 --> 00:06:06.410 so this means this is not working for me at the moment, 00:06:06.410 --> 00:06:08.860 I still need to debug it and figure out why not. 00:06:08.860 --> 00:06:10.760 But this should work for most of you. 00:06:10.760 --> 00:06:12.000 If this doesn't work though, 00:06:12.000 --> 00:06:13.060 it's good that I have a problem, 00:06:13.060 --> 00:06:15.140 because I can show you an alternative way of doing it 00:06:15.140 --> 00:06:16.400 that will work. 00:06:16.400 --> 00:06:17.360 If that doesn't work, 00:06:17.360 --> 00:06:19.250 click on terminal 00:06:19.250 --> 00:06:22.000 and then make sure that you've got this pair of brackets 00:06:22.000 --> 00:06:23.410 with movies at the start. 00:06:23.410 --> 00:06:24.243 That's gonna show you 00:06:24.243 --> 00:06:26.470 that you are currently in a virtual environment 00:06:26.470 --> 00:06:28.100 and anything you install 00:06:28.100 --> 00:06:31.320 is going to be installed in the virtual environment. 00:06:31.320 --> 00:06:35.710 And then we're gonna type easy_install -U, 00:06:35.710 --> 00:06:40.710 sorry that's _install, -U, pip. 00:06:40.940 --> 00:06:42.950 And that's going to update PIP. 00:06:42.950 --> 00:06:45.920 Now, again, try to use the other method if you can 00:06:45.920 --> 00:06:47.400 because it's gonna be easier. 00:06:47.400 --> 00:06:48.760 So once we've go this, 00:06:48.760 --> 00:06:53.350 we can go ahead and install psycopg2-binary. 00:06:53.350 --> 00:06:55.970 So again, we can go over to the settings 00:06:55.970 --> 00:06:57.200 or preferences on Mac, 00:06:57.200 --> 00:06:59.950 make sure that we've got this PIP installed there 00:06:59.950 --> 00:07:03.690 and we're going to simply click on the plus icon. 00:07:03.690 --> 00:07:07.800 Find here psycopg2-binary. 00:07:07.800 --> 00:07:09.800 Make sure to spell things correctly there 00:07:09.800 --> 00:07:12.643 and just install the package like that. 00:07:13.630 --> 00:07:15.650 Hopefully it'll install successfully. 00:07:15.650 --> 00:07:17.100 If it doesn't, just leave a question 00:07:17.100 --> 00:07:17.933 in the course Q and A 00:07:17.933 --> 00:07:19.110 and we'll help you out with that 00:07:19.110 --> 00:07:20.510 and press OK then. 00:07:20.510 --> 00:07:22.140 Now to verify that it works, 00:07:22.140 --> 00:07:23.820 we're gonna create a new file. 00:07:23.820 --> 00:07:25.590 So we're gonna right click on our project, 00:07:25.590 --> 00:07:27.000 that's the movies project. 00:07:27.000 --> 00:07:28.483 Click on New Python File. 00:07:29.360 --> 00:07:32.010 And then create it, for example, app.py 00:07:32.010 --> 00:07:33.250 and here all we have to do 00:07:33.250 --> 00:07:35.363 is type import psycopg2, 00:07:36.400 --> 00:07:38.190 right click on app.py, 00:07:38.190 --> 00:07:39.780 and run it. 00:07:39.780 --> 00:07:42.090 Hopefully you get nothing. 00:07:42.090 --> 00:07:45.130 No red angry text telling you there's an error. 00:07:45.130 --> 00:07:47.160 If you do get angry red text, 00:07:47.160 --> 00:07:49.530 then try to find out why that is, 00:07:49.530 --> 00:07:50.930 maybe put the error in Google 00:07:50.930 --> 00:07:52.100 and see if you can figure it out 00:07:52.100 --> 00:07:53.850 because there can be a few things that happen. 00:07:53.850 --> 00:07:55.640 But if you find that you can't figure it out, 00:07:55.640 --> 00:07:56.787 leave a question in the course Q and A 00:07:56.787 --> 00:07:58.950 and we can help you find a solution. 00:07:58.950 --> 00:08:00.130 'Course, we don't know the answers 00:08:00.130 --> 00:08:01.850 to every possible error that can happen 00:08:01.850 --> 00:08:04.290 when installing psycopg2-binary 00:08:04.290 --> 00:08:05.610 but we can help you out. 00:08:05.610 --> 00:08:08.360 But, hopefully, you get no issues whatsoever 00:08:08.360 --> 00:08:10.810 and everything works just fine, 00:08:10.810 --> 00:08:14.260 then we are ready to start using psycopg2 00:08:14.260 --> 00:08:17.430 to actually connect to a PostgreS database. 00:08:17.430 --> 00:08:20.690 So, this was a long installation process, 00:08:20.690 --> 00:08:21.920 but now that we're here, 00:08:21.920 --> 00:08:24.270 all we have to do is import psycopg2 00:08:25.110 --> 00:08:28.880 and then in the URL, enter your ElephantSQL URL, 00:08:28.880 --> 00:08:30.470 so that's the entire thing that we got 00:08:30.470 --> 00:08:33.220 from ElephantSQL, I'm just gonna bring it up right now, 00:08:37.500 --> 00:08:38.650 So just paste it in there, 00:08:38.650 --> 00:08:41.590 I know it's pretty long but don't worry about that. 00:08:41.590 --> 00:08:43.580 And then what we wanna do is connect. 00:08:43.580 --> 00:08:47.330 So we'll do something like connection = psycopg2.connect 00:08:47.330 --> 00:08:49.110 and paste in the URL. 00:08:49.110 --> 00:08:52.470 Psycopg2 is smart enough to extract a username, 00:08:52.470 --> 00:08:54.190 password and host name and port name 00:08:54.190 --> 00:08:56.050 and everything from this URL 00:08:56.050 --> 00:08:57.850 so you don't have to do it yourself. 00:08:57.850 --> 00:09:01.700 Now, in psycopg2, as we will learn in the next few videos, 00:09:01.700 --> 00:09:04.950 we always have to create a cursor to execute a query. 00:09:04.950 --> 00:09:07.910 It's not like SQLite where we can execute queries directly 00:09:07.910 --> 00:09:11.000 on the connection and it creates a cursor for us. 00:09:11.000 --> 00:09:12.370 We have to do it ourselves, 00:09:12.370 --> 00:09:16.490 so we'll do cursor = connection.cursor 00:09:16.490 --> 00:09:17.580 and then we can do something like 00:09:17.580 --> 00:09:21.763 cursor.execute select star from users. 00:09:23.060 --> 00:09:25.880 And then we can, for example, fetch the first row. 00:09:25.880 --> 00:09:29.810 So at first user is equal to cursor.fetchone 00:09:31.830 --> 00:09:33.893 and then we can print the first user. 00:09:34.930 --> 00:09:37.833 Remember, always at the end, connection.close. 00:09:38.800 --> 00:09:40.100 All right, let's run this. 00:09:40.100 --> 00:09:41.670 Something important to keep in mind 00:09:41.670 --> 00:09:42.990 when working with PyCharm 00:09:42.990 --> 00:09:46.930 is that there are two main ways of running anything. 00:09:46.930 --> 00:09:48.880 You could right click on the file and run it 00:09:48.880 --> 00:09:52.350 and this is the sure-fire code you want to run. 00:09:52.350 --> 00:09:53.270 And now the other way 00:09:53.270 --> 00:09:55.400 is to click the play button here at the top right, 00:09:55.400 --> 00:09:56.740 but then when you click that, 00:09:56.740 --> 00:09:58.980 what you're running is this. 00:09:58.980 --> 00:10:01.850 This here is a run configuration 00:10:01.850 --> 00:10:03.770 and at the moment we only have one, 00:10:03.770 --> 00:10:05.500 because we only have one file. 00:10:05.500 --> 00:10:07.830 Whenever you run a file in PyCharm, 00:10:07.830 --> 00:10:10.180 PyCharm will create a run configuration for you 00:10:10.180 --> 00:10:11.470 and save it up here. 00:10:11.470 --> 00:10:12.670 You can then select one 00:10:12.670 --> 00:10:15.580 and run it with the play button there. 00:10:15.580 --> 00:10:17.740 So here you can see that we ran all of this 00:10:17.740 --> 00:10:21.630 and we get the output which is our user from our table. 00:10:21.630 --> 00:10:24.190 If you're confused as to why we're importing psycopg2 00:10:24.190 --> 00:10:25.390 and not psycopg2-binary, 00:10:26.410 --> 00:10:28.950 it's because we're only ever going to install either 00:10:28.950 --> 00:10:31.860 psycopg2-binary or psycopg2. 00:10:31.860 --> 00:10:35.500 They both create the psycopg2 package 00:10:35.500 --> 00:10:36.780 in our virtual environment. 00:10:36.780 --> 00:10:38.360 They just go about creating it 00:10:38.360 --> 00:10:40.430 and installing it in two different ways. 00:10:40.430 --> 00:10:43.120 That's why one of them is easier to install than the other. 00:10:43.120 --> 00:10:46.270 But in both cases, you end up with the exact same code 00:10:46.270 --> 00:10:47.860 that we interact with. 00:10:47.860 --> 00:10:49.340 All right, now that we've created a project 00:10:49.340 --> 00:10:51.720 and tested that psycopg2 is working, 00:10:51.720 --> 00:10:53.480 we're ready to start migrating 00:10:53.480 --> 00:10:56.250 our movie watchlist project from the last section 00:10:56.250 --> 00:10:58.690 over to psycopg2. 00:10:58.690 --> 00:11:02.000 So to start, I would delete this file here. 00:11:02.000 --> 00:11:03.520 So I'm gonna go ahead and do that 00:11:03.520 --> 00:11:05.020 because we don't need it anymore, 00:11:05.020 --> 00:11:07.940 and copy all of the movie watchlist code files 00:11:07.940 --> 00:11:11.370 into this project so that we can start the migration. 00:11:11.370 --> 00:11:12.750 All right, let's do that 00:11:12.750 --> 00:11:13.890 and I'll meet you again here 00:11:13.890 --> 00:11:15.170 in the next video. 00:11:15.170 --> 00:11:16.003 See you soon.