How To Use Local Db In Visual Studio For Mac
By Rick Anderson and Joe Audette
You can use LocalDB only with your local machine (Dev environment).It won't use (or work) with Production environment.LocalDB won't Run as a service. It works only with launched process. So at the time when you migrate your DB into production, You have to use Full featured SQL server 2012 with Management studio. Log onto your Mac server; Open 'System Preferences' Open 'Sharing' Check the check-box for 'Remote login' 3. Making the connection. Log onto your server; With your server connection open, open Visual Studio on your local machine; In Visual Studio on your local machine go to: Tools Options; Xamarin iOS Settings; click Find Xamarin Mac Agent.
View or download sample code (how to download).
The RazorPagesMovieContext object handles the task of connecting to the database and mapping Movie objects to database records. The database context is registered with the Dependency Injection container in the ConfigureServices method in Startup.cs:
The ASP.NET Core Configuration system reads the ConnectionString. For local development, it gets the connection string from the appsettings.json file.
The name value for the database (Database={Database name}) will be different for your generated code. The name value is arbitrary.
When the app is deployed to a test or production server, an environment variable can be used to set the connection string to a real database server. See Configuration for more information.
SQL Server Express LocalDB
LocalDB is a lightweight version of the SQL Server Express database engine that's targeted for program development. LocalDB starts on demand and runs in user mode, so there's no complex configuration. By default, LocalDB database creates *.mdf files in the C:Users<user> directory.
From the View menu, open SQL Server Object Explorer (SSOX).
Right click on the
Movietable and select View Designer:
Note the key icon next to ID. By default, EF creates a property named ID for the primary key.
Right click on the
Movietable and select View Data:
SQLite
The SQLite website states:
SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine. SQLite is the most used database engine in the world.
There are many third party tools you can download to manage and view a SQLite database. The image below is from DB Browser for SQLite. If you have a favorite SQLite tool, leave a comment on what you like about it.
Note
For this tutorial you use the Entity Framework Core migrations feature where possible. Migrations updates the database schema to match changes in the data model. However, migrations can only do the kinds of changes that the EF Core provider supports, and the SQLite provider's capabilities are limited. For example, adding a column is supported, but removing or changing a column is not supported. If a migration is created to remove or change a column, the ef migrations add command succeeds but the ef database update command fails. Due to these limitations, this tutorial doesn't use migrations for SQLite schema changes. Instead, when the schema changes, you drop and re-create the database.
The workaround for the SQLite limitations is to manually write migrations code to perform a table rebuild when something in the table changes. A table rebuild involves:
Mtf for large format lenses online. And nowadays the Sigma f1.4 are sharp wide open, so there is no difference to fullframe in DOF anymore. I also have a Zenza Bronica ETRSi and a Fuji GX680 and shoot wide open @f2.8 but that's never getting close to a f1.2 lens. Today, with using the same technology it's again better in dynamic Range but it won't beat the DOF of an f0.95 Leica lens anytime soon;)Probably NEVER.
- Creating a new table.
- Copying data from the old table to the new table.
- Dropping the old table.
- Renaming the new table.
For more information, see the following resources:
Seed the database
Create a new class named SeedData in the Models folder with the following code:
If there are any movies in the DB, the seed initializer returns and no movies are added.
Add the seed initializer
In Program.cs, modify the Main method to do the following:
- Get a DB context instance from the dependency injection container.
- Call the seed method, passing to it the context.
- Dispose the context when the seed method completes.
The following code shows the updated Program.cs file.
The following exception occurs when Update-Database has not been run:
SqlException: Cannot open database 'RazorPagesMovieContext-' requested by the login. The login failed.Login failed for user 'user name'.
Test the app
Delete all the records in the DB. You can do this with the delete links in the browser or from SSOX
Force the app to initialize (call the methods in the
Startupclass) so the seed method runs. To force initialization, IIS Express must be stopped and restarted. You can do this with any of the following approaches:Right click the IIS Express system tray icon in the notification area and tap Exit or Stop Site:
- If you were running VS in non-debug mode, press F5 to run in debug mode.
- If you were running VS in debug mode, stop the debugger and press F5.
Delete all the records in the DB (So the seed method will run). Stop and start the app to seed the database.
The app shows the seeded data.
The next tutorial will improve the presentation of the data.
Additional resources
View or download sample code (how to download).
The RazorPagesMovieContext object handles the task of connecting to the database and mapping Movie objects to database records. The database context is registered with the Dependency Injection container in the ConfigureServices method in Startup.cs:
For more information on the methods used in ConfigureServices, see:
- EU General Data Protection Regulation (GDPR) support in ASP.NET Core for
CookiePolicyOptions.
The ASP.NET Core Configuration system reads the ConnectionString. For local development, it gets the connection string from the appsettings.json file.
The name value for the database (Database={Database name}) will be different for your generated code. The name value is arbitrary.
When the app is deployed to a test or production server, an environment variable can be used to set the connection string to a real database server. See Configuration for more information.
SQL Server Express LocalDB
LocalDB is a lightweight version of the SQL Server Express database engine that's targeted for program development. LocalDB starts on demand and runs in user mode, so there's no complex configuration. By default, LocalDB database creates *.mdf files in the C:/Users/<user/> directory.
From the View menu, open SQL Server Object Explorer (SSOX).
Right click on the
Movietable and select View Designer:
Note the key icon next to ID. By default, EF creates a property named ID for the primary key.
Right click on the
Movietable and select View Data:
SQLite
The SQLite website states:
SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine. SQLite is the most used database engine in the world.
There are many third party tools you can download to manage and view a SQLite database. The image below is from DB Browser for SQLite. If you have a favorite SQLite tool, leave a comment on what you like about it.
Note
For this tutorial you use the Entity Framework Core migrations feature where possible. Migrations updates the database schema to match changes in the data model. However, migrations can only do the kinds of changes that the EF Core provider supports, and the SQLite provider's capabilities are limited. For example, adding a column is supported, but removing or changing a column is not supported. If a migration is created to remove or change a column, the ef migrations add command succeeds but the ef database update command fails. Due to these limitations, this tutorial doesn't use migrations for SQLite schema changes. Instead, when the schema changes, you drop and re-create the database.
The workaround for the SQLite limitations is to manually write migrations code to perform a table rebuild when something in the table changes. A table rebuild involves:
- Creating a new table.
- Copying data from the old table to the new table.
- Dropping the old table.
- Renaming the new table.
For more information, see the following resources:
SQLite
The SQLite website states:
SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine. SQLite is the most used database engine in the world.
There are many third party tools you can download to manage and view a SQLite database. The image below is from DB Browser for SQLite. If you have a favorite SQLite tool, leave a comment on what you like about it.
Note
For this tutorial you use the Entity Framework Core migrations feature where possible. Migrations updates the database schema to match changes in the data model. However, migrations can only do the kinds of changes that the EF Core provider supports, and the SQLite provider's capabilities are limited. For example, adding a column is supported, but removing or changing a column is not supported. If a migration is created to remove or change a column, the ef migrations add command succeeds but the ef database update command fails. Due to these limitations, this tutorial doesn't use migrations for SQLite schema changes. Instead, when the schema changes, you drop and re-create the database.
The workaround for the SQLite limitations is to manually write migrations code to perform a table rebuild when something in the table changes. A table rebuild involves:
- Creating a new table.
- Copying data from the old table to the new table.
- Dropping the old table.
- Renaming the new table.
For more information, see the following resources:
Seed the database
Create a new class named SeedData in the Models folder with the following code:
If there are any movies in the DB, the seed initializer returns and no movies are added.
Add the seed initializer
In Program.cs, modify the Main method to do the following:
- Get a DB context instance from the dependency injection container.
- Call the seed method, passing to it the context.
- Dispose the context when the seed method completes.
The following code shows the updated Program.cs file.
A production app would not call Database.Migrate. It's added to the preceding code to prevent the following exception when Update-Database has not been run:
SqlException: Cannot open database 'RazorPagesMovieContext-21' requested by the login. The login failed.Login failed for user 'user name'.
Test the app
Delete all the records in the DB. You can do this with the delete links in the browser or from SSOX
Force the app to initialize (call the methods in the
Startupclass) so the seed method runs. To force initialization, IIS Express must be stopped and restarted. You can do this with any of the following approaches:Right-click the IIS Express system tray icon in the notification area and tap Exit or Stop Site:
- If you were running VS in non-debug mode, press F5 to run in debug mode.
- If you were running VS in debug mode, stop the debugger and press F5.
Delete all the records in the DB (So the seed method will run). Stop and start the app to seed the database.
The app shows the seeded data.
Delete all the records in the DB (So the seed method will run). Stop and start the app to seed the database.
The app shows the seeded data.
The app shows the seeded data:
The next tutorial will clean up the presentation of the data.