一个人(一次)可以在一次交易中重组Firebird表吗? [英] Can one (repeatedly) restructure a Firebird table in a single transaction?

问题描述

通常，我会像这样在A列上进行相对复杂的数据类型更改:

Normally, I'd do a relatively complicated change of data type on column A like this:

• 创建新数据类型的列B
• 将B设置为包含从A派生的新值
• 丢弃A
• 将B重命名为A

为了保证我的数据模型的有效性，我想在一次交易中执行这样的重组.到目前为止，我还无法做到这一点，因为根据隔离级别的不同，要么认为B不存在，要么不允许我重命名B(与并发更新发生更新冲突")，或者否发生错误，但B为空.是否可以执行我要求的操作-我很想看看如何-还是在两者之间绝对需要COMMIT?

To guarantee the validity of my data model, I'd like to perform such restructuring within a single transaction. So far, I have not been able to do that, because, depending on the isolation level, either B is not considered to exist yet, or I'm not allowed to rename B ("update conflicts with concurrent update"), or no errors occur but B is empty. Is it possible to perform to do what I ask - I'd love to see how - or is it absolutely required to COMMIT in between?

推荐答案

在使用似乎更合适的搜索词(元数据)以及通过de Firebird支持小组进行搜索之后，我发现这显然是不可能的.解决方法是分步进行迁移，并将其与备份结合在一起(这绝不是一个坏主意).

After searching using apparently more appropriate search terms (metadata), as well as via de Firebird support groups, I found that this is clearly not possible. The workaround is to do the migration in steps and combine it with backups (never a bad idea).

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