是的，你确实需要更新_MigrationHistory表中的ContextKey。代码：

Yes, you do indeed need to update the ContextKey in the__MigrationHistory table. Code:

UPDATE [dbo].[__MigrationHistory] 
   SET [ContextKey] = 'New_Namespace.Migrations.Configuration'
 WHERE [ContextKey] = 'Old_Namespace.Migrations.Configuration'

使用EF6重命名名称空间的主题：

A good read on the topic of renaming namespaces with EF6:

http://jameschambers.com/2014/02/changing-the-namespace-with-entity-framework-6-0-code-first-databases/ 一>