The startup template uses [EF Core Code First Migrations](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/) to create and maintain the database schema. Open the **Package Manager Console (PMC)** under the menu *Tools > NuGet Package Manager*.
The startup solution is configured to use [Entity Framework Core Code First Migrations](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/). Since we've changed the database mapping configuration, we should create a new migration and apply changes to the database.
> If you get an error like "*Your startup project ... doesn't reference Microsoft.EntityFrameworkCore.Design. This package is required for the Entity Framework Core Tools to work*", right click to the `Acme.BookStore.EntityFrameworkCore.DbMigrations` project and **Set as the Startup Project** and try again.
This will create a new migration class inside the `Migrations` folder of the `Acme.BookStore.EntityFrameworkCore.DbMigrations` project.
This will add a new migration class to the project:
Before updating the database, read the section below to learn how to seed some initial data to the database.
> If you are using another IDE than the Visual Studio, you can use `dotnet-ef` tool as [documented here](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/?tabs=dotnet-core-cli#create-a-migration).
> If you are using Visual Studio, you may want to use `Add-Migration Created_Book_Entity -c BookStoreMigrationsDbContext` and `Update-Database -c BookStoreMigrationsDbContext` commands in the *Package Manager Console (PMC)*. In this case, ensure that {{if UI=="MVC"}}`Acme.BookStore.Web`{{else if UI=="BlazorServer"}}`Acme.BookStore.Blazor`{{else if UI=="Blazor" || UI=="NG"}}`Acme.BookStore.HttpApi.Host`{{end}} is the startup project and `Acme.BookStore.EntityFrameworkCore.DbMigrations` is the *Default Project* in PMC.
Run the following command in the Package Manager Console (of the Visual Studio) to add a new database migration:
The startup solution is configured to use [Entity Framework Core Code First Migrations](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/). Since we've changed the database mapping configuration, we should create a new migration and apply changes to the database.
Open a command-line terminal in the directory of the `Acme.BookStore.EntityFrameworkCore.DbMigrations` project and type the following command:
````bash
Add-Migration "Added_AuthorId_To_Book"
dotnet ef migrations add Added_AuthorId_To_Book
````
> Ensure that the `Acme.BookStore.EntityFrameworkCore.DbMigrations` is the Default project and the `Acme.BookStore.DbMigrator` is the startup project, as always.
This should create a new migration class with the following code in its `Up` method:
* Declares the foreign key to the `AppAuthors` table.
> If you are using Visual Studio, you may want to use `Add-Migration Added_AuthorId_To_Book -c BookStoreMigrationsDbContext` and `Update-Database -c BookStoreMigrationsDbContext` commands in the *Package Manager Console (PMC)*. In this case, ensure that {{if UI=="MVC"}}`Acme.BookStore.Web`{{else if UI=="BlazorServer"}}`Acme.BookStore.Blazor`{{else if UI=="Blazor" || UI=="NG"}}`Acme.BookStore.HttpApi.Host`{{end}} is the startup project and `Acme.BookStore.EntityFrameworkCore.DbMigrations` is the *Default Project* in PMC.
@ -70,19 +70,25 @@ This is just like done for the `Book` entity before, so no need to explain again
## Create a new Database Migration
Open the **Package Manager Console** on Visual Studio and ensure that the **Default project** is `Acme.BookStore.EntityFrameworkCore.DbMigrations` in the Package Manager Console, as shown on the picture below. Also, set this project as the **startup project** (right click it on the solution explorer and click to "Set as Startup Project").
The startup solution is configured to use [Entity Framework Core Code First Migrations](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/). Since we've changed the database mapping configuration, we should create a new migration and apply changes to the database.
Run the following command to create a new database migration:
Open a command-line terminal in the directory of the `Acme.BookStore.EntityFrameworkCore.DbMigrations` project and type the following command:
> See the [Microsoft's documentation](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/) for more about the EF Core database migrations.
You can apply changes to the database using the following command, in the same command-line terminal:
````bash
dotnet ef database update
````
> If you are using Visual Studio, you may want to use `Add-Migration Added_Authors -c BookStoreMigrationsDbContext` and `Update-Database -c BookStoreMigrationsDbContext` commands in the *Package Manager Console (PMC)*. In this case, ensure that {{if UI=="MVC"}}`Acme.BookStore.Web`{{else if UI=="BlazorServer"}}`Acme.BookStore.Blazor`{{else if UI=="Blazor" || UI=="NG"}}`Acme.BookStore.HttpApi.Host`{{end}} is the startup project and `Acme.BookStore.EntityFrameworkCore.DbMigrations` is the *Default Project* in PMC.
liangshiwei
4 years ago
