Changing the Database Name

Before we look at the options for 0:00 changing the database name, let's delete our current database. 0:01 Deleting a database is not an operation that you'll do very often, 0:05 especially given that deleting a database 0:09 means that you'll forever lose access to the data contained within it. 0:12 Since our database is being generated by our app, and 0:16 it doesn't contain any data that we need to keep, it's safe to do. 0:20 We can delete our database by right-clicking here, 0:24 on the database in the SQL Server Object Explorer, and selecting Delete. 0:27 We'll be asked if we also want to delete the backup and 0:32 restore history information, and close any existing connections. 0:35 Be sure to check both options, that'll ensure that the delete operation will 0:40 succeed, even if we currently have an open connection to the database. 0:44 We're going to look at three options for 0:49 changing the name of the generated database. 0:51 The first and easiest of these options is to add a constructor to our context class. 0:54 And call the base class constructor that accepts a parameter for 0:59 the database name or connection string. 1:03 Public Context() then colon followed by the base keyword, 1:11 which allows us to call the members in the base class. 1:16 In this case, the base class constructor. 1:21 We'll take a look at how to use the connection string option in just a moment. 1:24 For now I'll just pass in the name of the database that 1:28 I'd like to use, ComicBookGallery. 1:33 Now let's run the app Press Enter to continue execution. 1:37 Then refresh the list of databases in the SQL Server Object Explorer window, 1:47 and we'll see our new ComicBookGallery database. 1:52 The DbContext base class constructor that we're calling 1:56 also accepts the database connection string. 1:59 This is our second option for changing the name of the database. 2:01 Here in Notepad, I have an example of a SQL Server database connection string. 2:05 The Data Source value is the name of the database server that we want to connect 2:10 to, which is a localdb instance named MSSQLLocalDB. 2:14 If we wanted to use a different database server other than localdb, or 2:19 a differently named instance, we could change this value. 2:24 The Initial Catalog value is the name of the database. 2:28 The Integrated Security value indicates that we want to use 2:32 Windows authentication. 2:35 And the MultipleActiveResultSets value indicates that we want to be able to run 2:38 more than one SQL batch on an open connection at the same time. 2:43 Setting this value to true, generally speaking, 2:47 helps to improve the overall performance of retrieving data from the database. 2:50 For more information about multiple active result sets, or 2:55 MARS, see the teacher's notes. 2:59 I'll copy and paste the connection string to the base class constructor method call. 3:02 Because our connection string contains a backslash, which is used to escape special 3:15 characters and text, we need to add another backslash before our backslash. 3:20 This tells the compiler that we actually want a backslash character, or 3:25 we can leave the single backslash and add an at sign before the starting quote. 3:30 This tells the compiler to treat our text as a verbatim string literal and 3:36 ignore any escape sequences contained within the text. 3:40 Let's also add the text ConnectionString as a suffix to the initial catalog name so 3:44 we don't have to delete our existing database. 3:49 Run the app again, and press Enter to continue execution. 4:00 Refresh the list of databases, and 4:06 we'll see our new ComicBookGalleryConnectionString database. 4:09 The third and last option for 4:13 changing the name of the database is to add a database connection string whose 4:15 name matches the name of our context class to our apps configuration file. 4:19 For console apps, we'll use the App.config file 4:24 in the root our project to add the necessary configuration. 4:28 For ASP.NET MVC apps, 4:32 you can use the web.config file in the root of the project. 4:34 We'll be covering how to use Entity Framework within MVC apps in another 4:37 course. 4:41 We start by adding a connectionStrings element right underneath 4:44 the root configuration element. 4:47 And within that element, we'll add an add element. 4:54 On the add element, 4:59 we'll add a name attribute whose value will match the name of our context class. 5:00 That's how EF will know to associate this connection string with our context. 5:06 Then we'll add a connection string attribute for our connection string, 5:11 which I'll cut and paste from the context class. 5:15 I'll also change the database name suffix to AppConfig. 5:35 Lastly, we'll add a providerName attribute to indicate which data provider to use. 5:52 Since we're using a SQL Server localdb database, 5:57 I'll set the value to System.Data.SqlClient. 6:02 Now that we have our connection string defined in the App.config file, 6:08 we can remove the constructor from the context class. 6:11 Run the app again, and press Enter to continue execution. 6:18 Refresh the list of databases, and 6:31 we'll see our new ComicBookGalleryAppConfig database. 6:33 Of the three options that we just saw, I like the third option, as it keeps 6:37 the configuration of our database location and name out of our code. 6:41 That makes it possible to change the location or 6:46 name of the database without having to rewrite our code. 6:49 Which is especially helpful when deployment applications 6:52 into other environments. 6:56 Let's remove the AppConfig suffix from the database name in the connectionString, so 6:59 our database name is just ComicBookGallery. 7:04 Then I'll do some cleanup and delete all of the existing databases. 7:13 Lastly, I'll run the app one more time, and 7:32 verify that our database is successfully created. 7:35 Refresh the list of databases, And here's our ComicBookGallery database. 7:39