EntityFrameworkCore.SqlServer.Seeding 5.0.12

SQL Server script seeding for Entity Framework Core

Data seeding is an important step in development process as it provides data for basic functional testing during development. However, data seeding may be also an integral part of the deployment where pre defined data such as lookups etc. may need to present on all environments where the application is deployed.

There are different ways of doing it and one of them is just use T-SQL script for SQL Server.

Overview

This package allows you to seed the data to SQL Server database using pure T-SQL scripts but in a managed fashion similar to Entity Framework Core migrations.

It makes your scripts part of the project and it also allows you to add new scripts by using IDE or in more managed way by CLI which comes as an additional cross-platform .NET Core global tool package.

Usage

Invoking the seeding

To use SQL script seeding with EF Core and targeting SQL Server database you need to bring in the NuGet package EntityFrameworkCore.SqlServer.Seeding which contains extension methods for dependency injection and ASP.NET Core pipeline.

dotnet add package EntityFrameworkCore.SqlServer.Seeding

Add script seeding to services collection and supply the connection string to the database

public void ConfigureServices(IServiceCollection services)
{
    ...
    var connectionString = Configuration.GetConnectionString("EmployeesDatabase");
    services.AddDbContext<EmployeesDatabaseContext>(options =>
           {
                options.UseSqlServer(connectionString,
                    x =>
                    {
                        x.MigrationsHistoryTable("__EFMigrationsHistory");
                        x.MigrationsAssembly(typeof(EmployeesDatabaseContext).Assembly.GetName().Name);
                    }
                );
            });

    services.AddScriptSeeding(connectionString, typeof(DbContextExtensions).Assembly, "Seedings");
    ...
}

Invoke the seeding in the pipeline by supplying the assembly where your scripts are sitting along with a folder under which scripts sit under project tree. The default value is "Seedings"

public void Configure(IApplicationBuilder app)
{
    ...
    using (var serviceScope = app.ApplicationServices
        .GetRequiredService<IServiceScopeFactory>()
        .CreateScope())
            {
                using (var context = serviceScope.ServiceProvider.GetService<EmployeesDatabaseContext>())
                {
                    context.Database.Migrate();
                }
            }
    app.SeedFromScripts();
    ...
}

Adding new seeding script

Seeding scripts can be added either manually from IDE or using CLI tool.

Adding seeding script manually

To add script manually you need to create new .sql file in your project and mark it as embedder resource. Make sure that your file name starts with timestamp in format yyyyMMddHHss. Here is a sample of a seeding SQL script:

  <ItemGroup Label="seeding">
    <None Remove="Seedings\20201017235255_Add_Initial_Employees.sql" />
    <EmbeddedResource Include="Seedings\20201017235255_Add_Initial_Employees.sql" />
  </ItemGroup>

Adding seeding script via CLI

As a first step you need to install global tool EntityFrameworkCore.SqlServer.Seeding.Tool which will help you add the seeding script to the project where you want to have your seeding scripts. I usually keep them together with migrations as a part of infrastructure.

dotnet tool install --global EntityFrameworkCore.SqlServer.Seeding.Tool 

From a command line (cmd, PowerShell, bash…) navigate to project folder where you want your scripts to sit. Simply add the script by invoking the previously installed global tool

seeding add "Add_Initial_Employees" -o Seedings

This will create new file under Seedings folder in your project tree. Once you run the main project, seeding files will be executed and recorded in __SeedingHistory table

What's new in 5.0.12

Added support for:

• Getting a list of all scripts
• Getting a list of pending scripts
• Getting a list of already executed scripts
• Getting the content of a specific script
• Executing specific script
• Executing pending scripts

These changes are introduced in order to support selective execution seeding as in the following example:

public void Configure(IApplicationBuilder app)
{
    ...
    using (var serviceScope = app.ApplicationServices
        .GetRequiredService<IServiceScopeFactory>()
        .CreateScope())
            {
                using (var context = serviceScope.ServiceProvider.GetService<EmployeesDatabaseContext>())
                {
                    var migrator = context.Database.GetService<IMigrator>();
                    var migrations = context.Database.GetPendingMigrations();
                    var seeder = serviceScope.ServiceProvider.GetService<ISeeder>();
                    var seeds = seeder.GetPendingScripts();

                    var commands = migrations.Concat(seeds).OrderBy(c => c).ToList();

                    if (commands != null && commands.Any())
                    {
                        foreach (var command in commands)
                        {
                            if (command.EndsWith(".sql"))
                                seeder.ExecuteScript(command);
                            else
                                migrator.Migrate(command);
                        }
                    }
                }
            }
    ...
}