CK's Notepad

[EF6] Entity Framework 6 Code First Migrations with Multiple Data Contexts (轉)

發表於 分類於 Disqus：

Ref: http://www.dotnet-tricks.com/Tutorial/entityframework/2VOa140214-Entity-Framework-6-Code-First-Migrations-with-Multiple-Data-Contexts.html

如何動態產生Database

如果利用Code first的方式，搭配DbMigration即可完成工作

  • DBContext.cs
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public class DemoContext : DbContext
    {
        public DemoContext() { }
        public DemoContext(string ConnectionString)
            : base(ConnectionString)
        {            
            Database.SetInitializer(new CustomInitializer());
            Database.Initialize(true);
        }        
        public DbSet<Blog> Blogs { get; set; }
    }
  • CustomInitializer.cs
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using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.Migrations;
using System.Data.Entity.Migrations.Infrastructure;
using System.Linq;

internal sealed class Configuration : DbMigrationsConfiguration<DemoContext>
{        
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
        MigrationsDirectory = @"Migration";
    }
  

    protected override void Seed(DemoContext context)
    {            
    }
}

class CustomInitializer : IDatabaseInitializer<DemoContext>
{
    public void InitializeDatabase(DemoContext context)
    {
        if (!context.Database.Exists() || !context.Database.CompatibleWithModel(false))
        {
            var configuration = new Configuration();
            configuration.TargetDatabase = new DbConnectionInfo(context.Database.Connection.ConnectionString, "System.Data.SqlClient");
            var migrator = new DbMigrator(configuration);                
            migrator.Update();                
        }
    }
}
  • client端
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using (var db = new AtaBookContext(connection1)){}
using (var db = new AtaBookContext(connection2)){}

connection1和connection2分別指到不同的資料庫，EF就會根據連線字串的設定產生相對應的資料庫