SQLite修改列 [英] SQLite Modify Column

问题描述

我需要修改SQLite数据库中的列，但是由于数据库已经在生产中，因此我必须以编程方式进行修改。从我的研究中，我发现要执行此操作，必须执行以下操作。

I need to modify a column in a SQLite database but I have to do it programatically due to the database already being in production. From my research I have found that in order to do this I must do the following.

• 使用新模式创建新表


• 将数据从旧表复制到新表


• 删除旧表


• 将新表重命名为旧表名称

• Create a new table with new schema
• Copy data from old table to new table
• Drop old table
• Rename new table to old tables name

对于一些相对容易的事情来说，这似乎是荒谬的工作。有没有更简单的方法？我需要做的就是更改现有列的约束并为其提供默认值。

That seems like a ridiculous amount of work for something that should be relatively easy. Is there not an easier way? All I need to do is change a constraint on a existing column and give it a default value.

推荐答案

那是更好的方法之一SQLite的已知缺点（ ALTER TABLE 不支持 MODIFY COLUMN ），但它在 SQLite未实现的SQL功能列表。

That's one of the better-known drawbacks of SQLite (no MODIFY COLUMN support on ALTER TABLE), but it's on the list of SQL features that SQLite does not implement.

编辑：删除了提及此内容的位，因为该页面已更新，表明不再适用了，因此将来的版本中可能会支持它。

edit: Removed bit that mentioned it may being supported in a future release as the page was updated to indicate that is no longer the case

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