WEBVTT 00:00.000 --> 00:06.570 Okay, so now that we've defined our DB context inside our program class, now we can supply the connection 00:06.570 --> 00:07.020 string. 00:07.020 --> 00:13.050 That Entity Framework needs to be able to make that connection to our database that we don't have yet, 00:13.050 --> 00:14.580 but we will do soon. 00:14.580 --> 00:20.520 So in order to provide this configuration where we get this from configuration, then we need to go 00:20.520 --> 00:22.500 to one of our configuration files. 00:22.500 --> 00:26.460 We've got Appsettings.json or App Settings development dot JSON. 00:26.460 --> 00:31.560 Now since we're in development mode and we're creating our application, then configuration settings 00:31.560 --> 00:37.530 that are not particularly private, such as our SQLite connection string can go in here. 00:37.530 --> 00:43.830 I'll talk about secrets a bit later about things where we don't necessarily want them to be visible 00:43.860 --> 00:49.860 to anybody else, but something like a SQLite connection string doesn't contain any password information 00:49.860 --> 00:52.710 and is perfectly fine to put in something. 00:52.710 --> 00:59.910 Even if we do put our code onto GitHub in a public repository, then we're okay with that information 00:59.910 --> 01:01.080 being out there. 01:01.080 --> 01:07.660 And like I say, I'll talk about what we do with more secure things, such as API keys that we might 01:07.660 --> 01:09.670 also want to supply to our application. 01:09.700 --> 01:13.330 I'll talk about that a bit later, but for now we're just getting things set up. 01:13.330 --> 01:15.880 So we want to supply a connection string. 01:15.880 --> 01:17.710 Now inside our app Settings development. 01:17.860 --> 01:20.290 Jason, be careful about where you add this. 01:20.380 --> 01:22.570 Try not to add it inside the logging section. 01:22.570 --> 01:23.380 That will not work. 01:23.380 --> 01:27.280 We need to add it below the logging section and these bracket colors. 01:27.280 --> 01:30.010 Please do pay attention to these because we want it below. 01:30.010 --> 01:33.580 In my case this pinky purple closing bracket. 01:33.580 --> 01:39.790 And then we can open quotes and we can choose connection strings a little snippet that helps us there. 01:39.790 --> 01:43.600 And this needs to match what we've supplied in our program class. 01:43.600 --> 01:47.500 So I've called this default connection which is kind of conventional. 01:47.500 --> 01:53.320 And that's what I'm going to supply inside our connection strings section inside here. 01:53.320 --> 01:54.640 And then we add a colon. 01:54.640 --> 01:58.540 And then we supply effectively a SQLite connection string. 01:58.540 --> 02:00.100 So these are very simple. 02:00.100 --> 02:02.170 It's just data source equals. 02:02.180 --> 02:08.900 And I'm just going to call it store DB because a SQLite database is stored in a file. 02:08.930 --> 02:14.600 Now, I've made a typo inside here that I do not get warned about. 02:14.630 --> 02:19.400 And specifically I've used dates instead of data. 02:19.790 --> 02:22.010 Now I don't get warned about this by the compiler. 02:22.010 --> 02:23.840 It doesn't know what this string should be. 02:23.870 --> 02:28.730 And in fact, strings you don't really get any help with from your compiler if you make a typo. 02:28.730 --> 02:33.680 If you make a mistake, guaranteed, it's just going to persist in your application, and you're not 02:33.680 --> 02:36.380 going to know until you create the database. 02:36.380 --> 02:37.640 Because this will not work. 02:37.640 --> 02:39.950 It needs to be data source. 02:40.220 --> 02:43.820 So do watch out for typos when you are using strings. 02:43.820 --> 02:46.070 It is something we have to use on occasions. 02:46.070 --> 02:48.650 And like I say, you don't get any help from the compiler. 02:48.680 --> 02:54.590 VS code isn't going to put any nasty squiggles under this, so please be careful. 02:54.620 --> 02:58.130 And if something doesn't work, it's just the first place you come back to check. 02:58.130 --> 03:00.620 Did I make a mistake in a string? 03:01.010 --> 03:04.650 So now we have that in place, we need to go ahead and create a migration. 03:04.650 --> 03:07.830 So we're going to open up the terminal is where we're going to do this. 03:08.250 --> 03:12.780 But when it comes to creating a migration using the. 03:12.960 --> 03:18.060 Net SDK, we actually need to add a tool to the SDK to help us do that. 03:18.060 --> 03:20.040 And it doesn't come by default. 03:20.040 --> 03:28.980 And if we just search for dotnet f nuget inside Google, then we can go to NuGet the sites. 03:28.980 --> 03:37.200 And this will give us the command that we need to use to go ahead and install this into our SDK effectively. 03:37.200 --> 03:37.440 So. 03:37.590 --> 03:39.660 Net tool install global. 03:39.900 --> 03:43.170 Net f version nine I'm just going to copy this command. 03:43.410 --> 03:46.140 Go back to VS code and paste in this command. 03:46.140 --> 03:47.700 It installs the tool globally. 03:47.700 --> 03:53.760 And if you've already got it fine it's going to update it to the latest version in this case version 03:53.760 --> 03:54.330 nine. 03:54.330 --> 03:57.840 So I'll press return on that just to make sure this tool does get installed. 03:57.840 --> 03:59.970 And in my case I already had a prior version. 03:59.970 --> 04:04.220 So it's updated that from 8.08 to 9 9.0.0. 04:04.250 --> 04:04.880 Great. 04:04.880 --> 04:11.450 And if you want to see what other tools you have, you can use a command like dotnet tool list dash 04:11.450 --> 04:14.000 G to see what global tools you have available. 04:14.000 --> 04:17.180 And I can see that I've got dotnet f available now. 04:17.180 --> 04:23.810 So very importantly before we do use this command that we're about to use, please ensure your dotnet 04:23.840 --> 04:26.420 API server is stopped. 04:26.420 --> 04:31.370 That is a requirement for what we're doing here and mine is not running. 04:31.370 --> 04:33.620 So I'm safe to use this command. 04:33.620 --> 04:38.660 And what we use here is we'll just make sure we've got dotnet f available. 04:38.660 --> 04:41.120 So I'm just going to type in dotnet f press return. 04:41.120 --> 04:45.650 And then we can see the help guide for Entity Framework command line tools. 04:45.650 --> 04:52.460 And we can use commands related to the database related to the Dbcontext and also related to migrations 04:52.460 --> 04:53.780 as well. 04:53.780 --> 05:02.930 So I'm going to use dotnet f migrations at and I'm just going to call it initial create. 05:03.260 --> 05:09.910 And I'm going to specify an output directory, because this is going to create some classes that define 05:09.940 --> 05:14.050 the database schema based on the code that we've written so far. 05:14.080 --> 05:18.400 So I'm going to output this into data forward slash migrations. 05:18.820 --> 05:19.960 This is optional. 05:19.960 --> 05:26.020 But if we do not supply list then it's just going to create a migrations folder in the root of our project. 05:26.020 --> 05:29.170 And I'd rather keep data related code together. 05:29.200 --> 05:30.430 So I'm going to press return. 05:30.430 --> 05:34.810 And that should go ahead and create a migration for us. 05:34.840 --> 05:35.530 Great. 05:35.530 --> 05:36.400 It's now been done. 05:36.400 --> 05:42.730 So if we go and take a look at what has been created and we go to our data folder inside here we've 05:42.730 --> 05:48.910 got a migrations folder and we have a few files inside here we've got the store context model snapshot 05:48.910 --> 05:50.950 and a designer file. 05:50.950 --> 05:55.720 And these files are generated to help us roll back to an earlier migration. 05:55.720 --> 05:57.640 So we're not interested in those. 05:57.640 --> 06:03.520 We're interested in this one the date time followed by initial create CSS. 06:03.520 --> 06:08.570 And this tells us what is going to happen when we apply this migration. 06:08.570 --> 06:10.910 It's going to create a table called products. 06:10.940 --> 06:15.200 It will also create a database if it has not already been created. 06:15.230 --> 06:17.750 So it creates a table called products. 06:18.350 --> 06:27.320 And it uses if I go back to the store context, it uses this name that we supply for the table name. 06:27.950 --> 06:28.790 Great. 06:29.090 --> 06:35.600 Because Entity Framework is convention based inside here we can see that we have a number of columns 06:35.600 --> 06:37.670 that are going to be created inside the table. 06:37.700 --> 06:45.830 Now the ID column this has got an annotation of SQLite autoincrement because it's called ID. 06:46.160 --> 06:52.460 And because this is going to be used as the primary key and because it's an integer, then Entity Framework 06:52.460 --> 06:57.920 knows that each time we add a new Productlist database, it's going to need a unique ID and it will 06:57.920 --> 06:58.820 autoincrement. 06:58.820 --> 07:03.890 So it will take the next available integer from what's already inside that table. 07:04.070 --> 07:09.160 Also, we have our name, description, price, etc. and none of these can be nullable. 07:09.190 --> 07:10.480 They've all got nullable false. 07:10.480 --> 07:14.860 So we're not allowed to create a product that doesn't have a name, for example. 07:14.860 --> 07:20.950 And also we have the primary key provided as the ID property based on the code that we've written. 07:20.950 --> 07:24.010 So Entity Framework is very convention based. 07:24.010 --> 07:25.450 We write minimal code. 07:25.450 --> 07:30.160 And then Entity Framework is going to infer certain things based on the code that we've written. 07:30.160 --> 07:32.140 And we've got two methods inside here. 07:32.140 --> 07:35.110 We've got an up method for when we apply this to our database. 07:35.110 --> 07:42.160 And we've got a down method as to what should happen if we want to remove this migration from our database. 07:42.190 --> 07:47.110 So let's go ahead and apply this migration to our database that we do not have yet. 07:47.110 --> 07:52.810 So still inside the API folder let's use another command from Entity Framework. 07:52.810 --> 07:56.800 And we'll say dotnet f database updates. 07:56.800 --> 07:59.290 And this is going to take a look at our migration. 07:59.290 --> 08:03.190 Create the database and apply that migration to that database. 08:03.190 --> 08:06.290 So I'll press return and we'll see what happens. 08:06.560 --> 08:08.690 And we can see some activity in our logs. 08:08.690 --> 08:11.900 And we can see that we're creating a table called products. 08:11.900 --> 08:14.930 And we've got some other information going on here. 08:14.960 --> 08:17.630 Creates another table called f migrations history. 08:17.630 --> 08:22.640 So it can keep track of what migrations have already been applied to our database. 08:22.640 --> 08:27.050 We can have more than one migration, and we will do as we create new entities. 08:27.050 --> 08:29.600 And we want to make database schema changes. 08:29.630 --> 08:35.720 We create more migrations so that the database can be updated with this new information. 08:35.750 --> 08:37.100 And great. 08:37.130 --> 08:37.610 Okay. 08:37.610 --> 08:41.690 So let's take a look at our database as it stands at the moment. 08:41.960 --> 08:46.280 Now another extension we installed earlier on was the SQLite viewer. 08:46.280 --> 08:53.390 If we take a look at our folder view inside Solution Explorer we can see that we have store DB. 08:53.390 --> 08:58.490 And if we click on this then we can see the contents of this database. 08:58.520 --> 09:04.010 Now in order to click on this and see what I'm seeing here, you do have to have that extension, the 09:04.010 --> 09:04.910 SQLite viewer. 09:04.910 --> 09:08.920 If you do not have this then it will not display anything inside here. 09:08.920 --> 09:11.050 It will just give you some kind of error. 09:11.080 --> 09:13.870 So what we have inside here is we can see a bunch of tables. 09:13.870 --> 09:15.370 We've got f migrations, history. 09:15.400 --> 09:17.920 F migrations, lock SQLite sequence. 09:17.950 --> 09:23.080 Don't worry about any of those tables, although you can take a look at the F migrations history, and 09:23.080 --> 09:29.290 it tells you the migration that's been applied along with the version of Entity Framework that was used, 09:29.290 --> 09:30.160 version nine. 09:30.160 --> 09:32.950 And we've also got our products table, which is currently empty. 09:32.980 --> 09:34.990 We don't have any products yet. 09:35.020 --> 09:40.870 And inside here we can see the columns or the column names that have been created, the ID with the 09:40.870 --> 09:45.010 primary key symbol, the name, description, price, picture, URL, etc.. 09:45.370 --> 09:52.090 So we've got our table created inside SQLite as well, and minimal effort to do this as well thanks 09:52.090 --> 09:53.470 to Entity Framework. 09:53.470 --> 10:00.670 But our table is empty and obviously we would like some demo products that our store is going to sell. 10:00.700 --> 10:04.420 And to do that, we're going to need to seed some data into our database. 10:04.420 --> 10:07.570 And we're going to take a look at how we do that next.