EntityFramework代码第一个自定义连接字符串和迁移 [英] EntityFramework code-first custom connection string and migrations

问题描述

当我使用默认连接字符串（从 app.config 中读取）创建一个上下文时，数据库被创建，并且迁移工作 - 基本上是一切顺序。而连接字符串是以程序方式创建的（使用 SqlConnectionStringBuilder ）：

• 数据库isn在数据库不存在时创建（方案 A ）;


• CreateDbIfNotExists（）创建数据库模型的最新版本，但调用迁移机制不（方案 B ）。

在 A 当我希望访问数据库时会抛出异常，因为 - 显然 - 它不在那里。在 B 数据库中正确创建迁移机制是不，标准连接字符串中的情况。

app.config ：
数据源= localhost\\SQLEXPRESS;初始目录= Db13;用户ID = xxx;密码= xxx

构建器：

  sqlBuilder.DataSource = x.DbHost; 
 sqlBuilder.InitialCatalog = x.DbName; 
 sqlBuilder.UserID = x.DbUser; 
 sqlBuilder.Password = x.DbPassword; 
  

初始化工具：

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
$

规范：
实体框架：5.0，DB：SQL Server Express 2008

解决方案

如果您的迁移无法正常尝试设置 Database.Initialize（true） 在DbContext ctor中。

  public CustomContext（DbConnection connection）
：base（connection， true）
 {
 Database.Initialize（true）; 
} 
  

我有类似的迁移问题。在我的解决方案中，我必须始终在ctor中设置数据库初始化器，如下所示

  public CustomContext（DbConnection connection）
 ：base（connection，true）
 {
 Database.SetInitializer（new CustomInitializer（））; 
 Database.Initialize（true）; 
} 
  

在自定义初始化工具中，您必须实现 InitalizeDatabase（CustomContex上下文）方法，例如。

  class CustomInitializer：IDatabaseInitializer< CustomContext> 
 {
 public void InitializeDatabase（CustomContext context）
 {
 if（！context.Database.Exists ||！context.Database.CompatibleWithModel（false））
 { 
 var configuration = new Configuration（）; 
 var migrator = new DbMigrator（configuration）; 
 migrator.Configuration.TargetDatabase = new DbConnectionInfo（context.Database.Connection.ConnectionString，System.Data.SqlClient）; 
 var migrations = migrator.GetPendingMigrations（）; 
 if（migrations.Any（））
 {
 var scriptor = new MigratorScriptingDecorator（migrator）; 
 string script = scriptor.ScriptUpdate（null，migrations.Last（））; 
 if（！String.IsNullOrEmpty（script））
 {
 context.Database.ExecuteSqlCommand（script）; 
} 
} 
} 
} 
} 
  

更新

When I create a context with a default connection string (as read from the app.config) the database is created and the migrations work - basically everything is in order. Whereas when the connection string is created programatically (using SqlConnectionStringBuilder):

• database isn't created when the database is not present (scenario A);
• CreateDbIfNotExists() creates the newest version of database model but the migration mechanisms are not invoked (scenario B).

In A an exception is thrown when I wish to access the database, as - obviously - it isn't there. In B database is created properly migration mechanisms are not called, as is the case in standard connection string.

app.config: "Data Source=localhost\\SQLEXPRESS;Initial Catalog=Db13;User ID=xxx;Password=xxx"

builder:

sqlBuilder.DataSource = x.DbHost;
sqlBuilder.InitialCatalog = x.DbName;
sqlBuilder.UserID = x.DbUser;
sqlBuilder.Password = x.DbPassword;

initializer:

Database.SetInitializer(
    new MigrateDatabaseToLatestVersion<
        MyContext,
        Migrations.Configuration
    >()
);

Specs: Entity Framework: 5.0, DB: SQL Server Express 2008

解决方案

If your migration does not work correctly try to set Database.Initialize(true) in DbContext ctor.

public CustomContext(DbConnection connection)
: base(connection, true)    
{    
        Database.Initialize(true);    
}    

I have similar problem with migrations. And in my solution I have to always set database initializer in ctor, like below

public CustomContext(DbConnection connection)
: base(connection, true)    
{    
        Database.SetInitializer(new CustomInitializer());
        Database.Initialize(true);    
}    

In custom initializer you have to implement InitalizeDatabase(CustomContex context) method, eg.

class CustomInitializer : IDatabaseInitializer<CustomContext>
{
    public void InitializeDatabase(CustomContext context)
    {
        if (!context.Database.Exists || !context.Database.CompatibleWithModel(false))
        {
            var configuration = new Configuration();
            var migrator = new DbMigrator(configuration);
            migrator.Configuration.TargetDatabase = new DbConnectionInfo(context.Database.Connection.ConnectionString, "System.Data.SqlClient");
            var migrations = migrator.GetPendingMigrations();
            if (migrations.Any())
            {
                var scriptor = new MigratorScriptingDecorator(migrator);
                string script = scriptor.ScriptUpdate(null, migrations.Last());
                if (!String.IsNullOrEmpty(script))
                {
                    context.Database.ExecuteSqlCommand(script);
                }
            }
        }
    }
}

UPDATED

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