You should never just log in and start entering "ALTER TABLE" commands to change a production database. The project I'm on has database on every customer site, and so every change to the database is made in two places, a dump file that is used to create a new database on a new customer site, and an update file that is run on every update which checks your current database version number against the highest number in the file, and updates your database in place. So for instance, the last couple of updates:

if [ $VERSION \< '8.0.108' ] ; then
  psql -U cosuser $dbName << EOF8.0.108
    BEGIN TRANSACTION;
    --
    -- Remove foreign key that shouldn't have been there.
    -- PCR:35665
    --
    ALTER TABLE     migratorjobitems
    DROP CONSTRAINT migratorjobitems_destcmaid_fkey;
    -- 
    -- Increment the version
    UPDATE          sys_info
    SET             value = '8.0.108'
    WHERE           key = 'DB VERSION';
    END TRANSACTION;
EOF8.0.108
fi

if [ $VERSION \< '8.0.109' ] ; then
  psql -U cosuser $dbName << EOF8.0.109
    BEGIN TRANSACTION;
    --
    -- I missed a couple of cases when I changed the legacy playlist
    -- from reporting showplaylistidnum to playlistidnum
    --
    ALTER TABLE     featureidrequestkdcs
    DROP CONSTRAINT featureidrequestkdcs_cosfeatureid_fkey;
    ALTER TABLE     featureidrequestkdcs
    ADD CONSTRAINT  featureidrequestkdcs_cosfeatureid_fkey
    FOREIGN KEY     (cosfeatureid)
    REFERENCES      playlist(playlistidnum)
    ON DELETE       CASCADE;
    --
    ALTER TABLE     ticket_system_ids
    DROP CONSTRAINT ticket_system_ids_showplaylistidnum_fkey;
    ALTER TABLE     ticket_system_ids
    RENAME          showplaylistidnum
    TO              playlistidnum;
    ALTER TABLE     ticket_system_ids
    ADD CONSTRAINT  ticket_system_ids_playlistidnum_fkey
    FOREIGN KEY     (playlistidnum)
    REFERENCES      playlist(playlistidnum)
    ON DELETE       CASCADE;
    -- 
    -- Increment the version
    UPDATE          sys_info
    SET             value = '8.0.109'
    WHERE           key = 'DB VERSION';
    END TRANSACTION;
EOF8.0.109
fi

我相信有更好的方法来做到这一点，但到目前为止，它对我来说是有效的。

在我们的业务中，我们使用数据库更改脚本。运行脚本时，它的名称存储在数据库中，并且不会再次运行，除非删除该行。脚本是基于日期、时间和代码分支命名的，因此可以控制执行。

在脚本在实际环境中运行之前，已经完成了大量的测试，所以一般来说，“oopsies”只发生在开发数据库上。

是的……我们的数据库是在ERwin中设计的，每个版本的ddl是自动生成的。ERwin文件保存在我们的源代码控制系统中(实际上，我们的工程文档也是如此)。

I've heard people say you absolutely have to keep your schemas in the database. I'm not sure I agree. This really depends on the system you're working with. If your system is relatively small and the data is not terribly important. And the the speed at which you need to bring another development environment online is crucial.. then yes.. you can benefit from it. However when your schema is useless without the data and the database is extremely large, it becomes virtually impossible to "source control" your database. Sure, you can still keep your DDL code in source control but that's essentially useless. You can't get the data needed without backup/restore.

在大型数据库开发工作中，我发现备份和恢复是首选的回滚选项。当然，你可以在源代码控制中保留过程、视图、函数等，但要保留表。SQL不是必需的。此外，如果您的部署过程是无懈可击的，那么您很可能永远不需要“回滚”您的生产环境。

Kira的主要用例之一是通过显式地将数据库外部的模式指定为代码来进行数据库升级。然后，它可以管理数据库，并将其从任何版本升级到任何版本。

必须阅读将数据库置于版本控制之下。查看K. Scott Allen的系列帖子。

When it comes to version control, the database is often a second or even third-class citizen. From what I've seen, teams that would never think of writing code without version control in a million years-- and rightly so-- can somehow be completely oblivious to the need for version control around the critical databases their applications rely on. I don't know how you can call yourself a software engineer and maintain a straight face when your database isn't under exactly the same rigorous level of source control as the rest of your code. Don't let this happen to you. Get your database under version control.