Choose Your Data Connection Dialog Box (Generate Database Wizard)
The Choose Your Data Connection dialog box is the part of the Create Database Wizard that enables you to specify the data source, connection options, and database to be used in your application. The database must exist before you run the wizard, although the database schema does not have to exist. The database must exist so that the wizard can determine column types for the target database based on property types in your model, and so that connection string information can be added to your application. When the wizard finishes, it generates data definition language (DDL) that you can use to create the database schema. For more information, see Generate Database Wizard (Entity Data Model Tools).
Which Data Connection Should Your Application Use to Connect to the Database?
Choose an existing connection from the drop-down list of connections, or click New Connection to open the Connection Properties dialog box and create a new connection to the database.
If you are logging onto the database server by using SQL Server Authentication, you must decide whether to include sensitive data (such as user name and password) in the connection string, or whether you will handle the sensitive data in your application code. Select the option that corresponds to your choice. For more information about security issues when you use connection strings, see Protecting Connection Information (ADO.NET).
Entity Connection String
The Entity Connection String box displays the connection information based on your server and database connection selections.
Save Entity Connection Settings in App.Config or Web.Config File
To save entity connection settings in the App.Config or Web.Config file (depending on the project type), select Save the entity connection settings. Type a name for the connection or use the provided default name.
Saving connection strings in the configuration file simplifies maintaining your application if the database connection changes. If the database connection changes, you can edit the connection string in the configuration file. This means that you do not have to edit the source code and recompile the application.
Information is stored in the App.Config or Web.Config file as plain text. To reduce the risk of unauthorized access to sensitive information, you might want to encrypt your data.