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我目前的宠物项目是一个独立于语言的数据库迁移库（ Google Code 上的Wizardby）。它非常受 ActiveRecord Migrations 的启发，但也有一些细节。例如，执行一些基本的“类型推断”，因此您不必指定 FK 列的类型。仅给定“升级”序列即可生成“降级”脚本也足够聪明。尽管迁移是用特殊的 DSL 编写的，但该工具主要针对 .NET 项目。它也是独立于数据库平台的。

下面是语法的快速浏览：

  migration "Blog" revision => 1:
    type-aliases:
      type-alias N type => String, length => 200, nullable => false, default => ""

    defaults:
      default-primary-key ID type => Int32, nullable => false, identity => true

    version 1:
      add table Author:
        FirstName type => N
        LastName type => N
        EmailAddress type => N, unique => true
        Login type => N, unique => true
        Password type => Binary, length => 64, nullable => true

      add table Tag:
        Name type => N

      add table Blog:
        Name type => N
        Description type => String, nullable => false

      add table BlogPost:
        Title type => N
        Slug type => N
        BlogID references => Blog
        AuthorID references => Author

      add table BlogPostTagJunction primary-key => false:
        BlogPostID references => BlogPost
        TagID references => Tag

    version 2:
      add table BlogPostComment:
        BlogPostID references => BlogPost
        AuthorEmailAddress type => N
        Content type => String, nullable => false

    version 3:
      add table Media:
        TypeID type => Int32
        Name type => N
        MimeType type => N
        Length type => Int32
        BlogPostID nullable => true, references => BlogPost
        BlogPostCommentID nullable => true, references => BlogPostComment

      add table User:
        Login type => String, length => 200, nullable => false
        Password type => Binary, length => 64, nullable => false

        index IX_Login columns => [ID, [Login, desc]], unique => true

    version 4:
        add table Forum:
          Name type => String, length => 200, nullable => false
        add column ModeratorUserID nullable => false, references => User

    version 5:
        remove index IX_Login table => User

    version 6:
        add index IX_Login table => User, columns => [ID, [Login, desc]], unique => true

    version 7:
        BlogAuthorJunction primary-key => false:
            BlogID references => Blog
            AuthorID references => Author

        execute native-sql upgrade-resource => InsertSeedData, downgrade-resource => DeleteSeedData

我知道那里有其他迁移库，但是，嘿，这是一个宠物项目！

The question is: what features do you expect from database migration toolkits in general and what can you say about this particular puppy syntax-wise?

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3 回答 3

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I like this syntax. In your sample you focused on changing structure. But what about data manipulation?

It's very often when in migration I have to modify data (for example add some dictionary data).

于 2009-03-09T22:23:16.020 回答
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I'd like to see the ability to verify that each revision has been applied to a database. So say for example version 3 added the table 'Media'. Since then versions 4 & 5 have been added to the database but somewhere along the line 'Johnny Q Expert' deleted the table 'Media'. Now comes version 6 which needs to alter the 'Media' table (which no longer exists) - a verify function could be useful which ensures a culmination of all changes made in versions 1 thru 5 are present in the database so the next version can be applied correctly.

于 2010-02-18T04:10:24.677 回答
2

From the looks of it I have to say that it is farily easy to follow and overall the structure looks pretty clean.

The biggest features that I'm looking for in something like this are as follows.

  1. Ability to make changes in a transaction to roll back should there be an issue. (Data integrity or otherwise)
  2. Ability to see the actual generated SQL scripts should the need arise
  3. Automatic rollback, if a failure occurs to the last version

I have other requirements regarding the moving of keys, indexes, and the such, but it looks like you have that already handled. For me it is really focused on the controls around the actual execution, and a quick, solid backout plan!

于 2009-03-09T17:39:32.600 回答