• Entity Framework Core tools reference


    Entity Framework Core tools reference - .NET Core CLI

    The command-line interface (CLI) tools for Entity Framework Core perform design-time development tasks. For example, they create migrations, apply migrations, and generate code for a model based on an existing database. The commands are an extension to the cross-platform dotnet command, which is part of the .NET Core SDK. These tools work with .NET Core projects.

    When using Visual Studio, consider using the Package Manager Console tools in lieu of the CLI tools. Package Manager Console tools automatically:

    • Works with the current project selected in the Package Manager Console without requiring that you manually switch directories.
    • Opens files generated by a command after the command is completed.
    • Provides tab completion of commands, parameters, project names, context types, and migration names.

    Installing the tools

    dotnet ef can be installed as either a global or local tool. Most developers prefer installing dotnet ef as a global tool using the following command:

    .NET Core CLI
    dotnet tool install --global dotnet-ef
    

    To use it as a local tool, restore the dependencies of a project that declares it as a tooling dependency using a tool manifest file.

    Update the tool tool using the following command:

    .NET Core CLI
    dotnet tool update --global dotnet-ef
    

    Before you can use the tools on a specific project, you'll need to add the Microsoft.EntityFrameworkCore.Design package to it.

    .NET Core CLI
    dotnet add package Microsoft.EntityFrameworkCore.Design
    

    Verify installation

    Run the following commands to verify that EF Core CLI tools are correctly installed:

    .NET Core CLI
    dotnet ef
    

    The output from the command identifies the version of the tools in use:

    Output
    
                         _/\__
                   ---==/    \
             ___  ___   |.    |
            | __|| __|  |  )   \
            | _| | _|   \_/ |  //|\
            |___||_|       /   \/\
    
    Entity Framework Core .NET Command-line Tools 2.1.3-rtm-32065
    
    <Usage documentation follows, not shown.>
    

    Update the tools

    Use dotnet tool update --global dotnet-ef to update the global tools to the latest available version. If you have the tools installed locally in your project use dotnet tool update dotnet-ef. Install a specific version by appending --version <VERSION> to your command. See the Update section of the dotnet tool documentation for more details.

    Using the tools

    Before using the tools, you might have to create a startup project or set the environment.

    Target project and startup project

    The commands refer to a project and a startup project.

    • The project is also known as the target project because it's where the commands add or remove files. By default, the project in the current directory is the target project. You can specify a different project as target project by using the --project option.

    • The startup project is the one that the tools build and run. The tools have to execute application code at design time to get information about the project, such as the database connection string and the configuration of the model. By default, the project in the current directory is the startup project. You can specify a different project as startup project by using the --startup-project option.

    The startup project and target project are often the same project. A typical scenario where they are separate projects is when:

    • The EF Core context and entity classes are in a .NET Core class library.
    • A .NET Core console app or web app references the class library.

    It's also possible to put migrations code in a class library separate from the EF Core context.

    Other target frameworks

    The CLI tools work with .NET Core projects and .NET Framework projects. Apps that have the EF Core model in a .NET Standard class library might not have a .NET Core or .NET Framework project. For example, this is true of Xamarin and Universal Windows Platform apps. In such cases, you can create a .NET Core console app project whose only purpose is to act as startup project for the tools. The project can be a dummy project with no real code — it is only needed to provide a target for the tooling.

    Why is a dummy project required? As mentioned earlier, the tools have to execute application code at design time. To do that, they need to use the .NET Core runtime. When the EF Core model is in a project that targets .NET Core or .NET Framework, the EF Core tools borrow the runtime from the project. They can't do that if the EF Core model is in a .NET Standard class library. The .NET Standard is not an actual .NET implementation; it's a specification of a set of APIs that .NET implementations must support. Therefore .NET Standard is not sufficient for the EF Core tools to execute application code. The dummy project you create to use as startup project provides a concrete target platform into which the tools can load the .NET Standard class library.

    ASP.NET Core environment

    To specify the environment for ASP.NET Core projects, set the ASPNETCORE_ENVIRONMENT environment variable before running commands.

    Starting in EF Core 5.0, additional arguments can also be passed into Program.CreateHostBuilder allowing you to specify the environment on the command-line:

    .NET Core CLI
    dotnet ef database update -- --environment Production
    

     Tip

    The -- token directs dotnet ef to treat everything that follows as an argument and not try to parse them as options. Any extra arguments not used by dotnet ef are forwarded to the app.

    Common options

    COMMON OPTIONS
    OptionShortDescription
    --json   Show JSON output.
    --context <DBCONTEXT> -c The DbContext class to use. Class name only or fully qualified with namespaces. If this option is omitted, EF Core will find the context class. If there are multiple context classes, this option is required.
    --project <PROJECT> -p Relative path to the project folder of the target project. Default value is the current folder.
    --startup-project <PROJECT> -s Relative path to the project folder of the startup project. Default value is the current folder.
    --framework <FRAMEWORK>   The Target Framework Moniker for the target framework. Use when the project file specifies multiple target frameworks, and you want to select one of them.
    --configuration <CONFIGURATION>   The build configuration, for example: Debug or Release.
    --runtime <IDENTIFIER>   The identifier of the target runtime to restore packages for. For a list of Runtime Identifiers (RIDs), see the RID catalog.
    --no-build   Don't build the project. Intended to be used when the build is up-to-date.
    --help -h Show help information.
    --verbose -v Show verbose output.
    --no-color   Don't colorize output.
    --prefix-output   Prefix output with level.

    Starting in EF Core 5.0, any additional arguments are passed to the application.

    dotnet ef database drop

    Deletes the database.

    Options:

    DOTNET EF DATABASE DROP
    OptionShortDescription
    --force -f Don't confirm.
    --dry-run   Show which database would be dropped, but don't drop it.

    The common options are listed above.

    dotnet ef database update

    Updates the database to the last migration or to a specified migration.

    Arguments:

    DOTNET EF DATABASE UPDATE
    ArgumentDescription
    <MIGRATION> The target migration. Migrations may be identified by name or by ID. The number 0 is a special case that means before the first migration and causes all migrations to be reverted. If no migration is specified, the command defaults to the last migration.

    Options:

    DOTNET EF DATABASE UPDATE
    OptionDescription
    --connection <CONNECTION> The connection string to the database. Defaults to the one specified in AddDbContext or OnConfiguring. Added in EF Core 5.0.

    The common options are listed above.

    The following examples update the database to a specified migration. The first uses the migration name and the second uses the migration ID and a specified connection:

    .NET Core CLI
    dotnet ef database update InitialCreate
    dotnet ef database update 20180904195021_InitialCreate --connection your_connection_string
    

    dotnet ef dbcontext info

    Gets information about a DbContext type.

    The common options are listed above.

    dotnet ef dbcontext list

    Lists available DbContext types.

    The common options are listed above.

    dotnet ef dbcontext scaffold

    Generates code for a DbContext and entity types for a database. In order for this command to generate an entity type, the database table must have a primary key.

    Arguments:

    DOTNET EF DBCONTEXT SCAFFOLD
    ArgumentDescription
    <CONNECTION> The connection string to the database. For ASP.NET Core 2.x projects, the value can be name=<name of connection string>. In that case the name comes from the configuration sources that are set up for the project.
    <PROVIDER> The provider to use. Typically this is the name of the NuGet package, for example: Microsoft.EntityFrameworkCore.SqlServer.

    Options:

    DOTNET EF DBCONTEXT SCAFFOLD
    OptionShortDescription
    --data-annotations -d Use attributes to configure the model (where possible). If this option is omitted, only the fluent API is used.
    --context <NAME> -c The name of the DbContext class to generate.
    --context-dir <PATH>   The directory to put the DbContext class file in. Paths are relative to the project directory. Namespaces are derived from the folder names.
    --context-namespace <NAMESPACE>   The namespace to use for the generated DbContext class. Note: overrides --namespace. Added in EF Core 5.0.
    --force -f Overwrite existing files.
    --output-dir <PATH> -o The directory to put entity class files in. Paths are relative to the project directory.
    --namespace <NAMESPACE> -n The namespace to use for all generated classes. Defaults to generated from the root namespace and the output directory. Added in EF Core 5.0.
    --schema <SCHEMA_NAME>...   The schemas of tables to generate entity types for. To specify multiple schemas, repeat --schema for each one. If this option is omitted, all schemas are included.
    --table <TABLE_NAME>... -t The tables to generate entity types for. To specify multiple tables, repeat -t or --table for each one. If this option is omitted, all tables are included.
    --use-database-names   Use table and column names exactly as they appear in the database. If this option is omitted, database names are changed to more closely conform to C# name style conventions.
    --no-onconfiguring   Suppresses generation of the OnConfiguring method in the generated DbContext class. Added in EF Core 5.0.
    --no-pluralize   Don't use the pluralizer. Added in EF Core 5.0

    The common options are listed above.

    The following example scaffolds all schemas and tables and puts the new files in the Models folder.

    .NET Core CLI
    dotnet ef dbcontext scaffold "Server=(localdb)mssqllocaldb;Database=Blogging;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -o Models
    

    The following example scaffolds only selected tables and creates the context in a separate folder with a specified name and namespace:

    .NET Core CLI
    dotnet ef dbcontext scaffold "Server=(localdb)mssqllocaldb;Database=Blogging;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -o Models -t Blog -t Post --context-dir Context -c BlogContext --context-namespace New.Namespace
    

    The following example reads the connection string from the project's configuration set using the Secret Manager tool.

    .NET Core CLI
    dotnet user-secrets set ConnectionStrings.Blogging "Data Source=(localdb)MSSQLLocalDB;Initial Catalog=Blogging"
    dotnet ef dbcontext scaffold Name=ConnectionStrings.Blogging Microsoft.EntityFrameworkCore.SqlServer
    

    dotnet ef dbcontext script

    Generates a SQL script from the DbContext. Bypasses any migrations. Added in EF Core 3.0.

    Options:

    DOTNET EF DBCONTEXT SCRIPT
    OptionShortDescription
    --output <FILE> -o The file to write the result to.

    The common options are listed above.

    dotnet ef migrations add

    Adds a new migration.

    Arguments:

    DOTNET EF MIGRATIONS ADD
    ArgumentDescription
    <NAME> The name of the migration.

    Options:

    DOTNET EF MIGRATIONS ADD
    OptionShortDescription
    --output-dir <PATH> -o The directory use to output the files. Paths are relative to the target project directory. Defaults to "Migrations".
    --namespace <NAMESPACE> -n The namespace to use for the generated classes. Defaults to generated from the output directory. Added in EF Core 5.0.

    The common options are listed above.

    dotnet ef migrations list

    Lists available migrations.

    Options:

    DOTNET EF MIGRATIONS LIST
    OptionDescription
    --connection <CONNECTION> The connection string to the database. Defaults to the one specified in AddDbContext or OnConfiguring. Added in EF Core 5.0.
    --no-connect Don't connect to the database. Added in EF Core 5.0.

    The common options are listed above.

    dotnet ef migrations remove

    Removes the last migration (rolls back the code changes that were done for the migration).

    Options:

    DOTNET EF MIGRATIONS REMOVE
    OptionShortDescription
    --force -f Revert the migration (roll back the changes that were applied to the database).

    The common options are listed above.

    dotnet ef migrations script

    Generates a SQL script from migrations.

    Arguments:

    DOTNET EF MIGRATIONS SCRIPT
    ArgumentDescription
    <FROM> The starting migration. Migrations may be identified by name or by ID. The number 0 is a special case that means before the first migration. Defaults to 0.
    <TO> The ending migration. Defaults to the last migration.

    Options:

    DOTNET EF MIGRATIONS SCRIPT
    OptionShortDescription
    --output <FILE> -o The file to write the script to.
    --idempotent -i Generate a script that can be used on a database at any migration.
    --no-transactions   Don't generate SQL transaction statements. Added in EF Core 5.0.

    The common options are listed above.

    The following example creates a script for the InitialCreate migration:

    .NET Core CLI
    dotnet ef migrations script 0 InitialCreate
    

    The following example creates a script for all migrations after the InitialCreate migration.

    .NET Core CLI
    dotnet ef migrations script 20180904195021_InitialCreate
    

    Additional resources

    Feedback

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    参考地址:https://docs.microsoft.com/en-us/ef/core/cli/dotnet
     
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  • 原文地址:https://www.cnblogs.com/devgis/p/14316540.html
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