EF 7迁移到现有数据库 [英] EF 7 Migration to Existing Database

问题描述

我正在使用ASP.Net 5和EF7进行Web项目。

I am working on a web project using ASP.Net 5 and EF7.

我已将所有表从现有数据库导入到项目中的模型中。但是，我在迁移方面遇到了问题。

I have imported all the tables from existing database onto my models in my project. However, I am having problems in regards with migrations.

我创建了初始迁移，对特定实体进行了一些更改，根据所做的更改创建了另一个迁移，现在要在数据库上应用更改。

I have created the initial migration, made some changes on particular entity, create another migration following the changes I have made and now want to apply the changes on the database.

在下面运行以下命令后：

After running this command below:

dnx ef数据库更新[Migration]

dnx试图对所有已存在的实体应用初始迁移数据库，这将导致以下错误：

the dnx is trying to apply the 'initial' migration with all the entities which are already in database and this causes an error as below:

{数据库中已经有一个名为['EntityName']的对象。 }

{ There is already an object named ['EntityName'] in the database. }

能否请您提供有关如何在现有数据库上进行迁移的建议？

Can you please advise on how to do the migration on the existing database?

感谢
Saeed

Thanks Saeed

推荐答案

在EF6中，您将使用进行迁移-IgnoreChanges 标志，它将在没有任何 Up（）代码的情况下拍摄模型的快照。如此处所示。

In EF6 you would run a migration with the -IgnoreChanges flag and it would take a snapshot of the model without any Up() code. This is missing from EF 7(EF Core) as indicated here.

目前的解决方法是从迁移的 Up（）代码中删除或注释掉现有数据库对象的代码，然后进行更新-数据库。随后的迁移将仅包括更改。

The workaround for now is delete or comment out the code for existing database objects from the Up() code of the migration and then update-database. Subsequent migrations will then include only the changes.

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