问题描述
我需要修改 SQLite 数据库中的一列，但由于数据库已经在生产中，我必须以编程方式进行.根据我的研究，我发现为了做到这一点，我必须执行以下操作.
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.
- 使用新架构创建一个新表
- 将数据从旧表复制到新表
- 放下旧桌子
- 将新表重命名为旧表名
对于应该相对容易的事情来说，这似乎是一项荒谬的工作.没有更简单的方法吗?我需要做的就是更改现有列的约束并为其指定默认值.
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
这是 SQLite 众所周知的缺点之一(在 ALTER TABLE 上没有 MODIFY COLUMN 支持)，但它位于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.
删除了提到它可能在未来版本中受支持的位，因为页面已更新以表明不再是这种情况
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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