如何在Rails迁移中将可为空的列更改为不可为空? [英] How to change a nullable column to not nullable in a Rails migration?

问题描述

我在先前的迁移中创建了一个日期列，并将其设置为可为空.现在，我想将其更改为不可为空.假设该数据库中存在空行，我该如何去做?我可以将这些列设置为Time.now，如果它们当前为空.

I created a date column in a previous migration and set it to be nullable. Now I want to change it to be not nullable. How do I go about doing this assuming there are null rows in that database? I'm ok with setting those columns to Time.now if they're currently null.

推荐答案

如果在迁移过程中这样做，则可能会这样:

If you do it in a migration then you could probably do it like this:

# Make sure no null value exist
MyModel.where(date_column: nil).update_all(date_column: Time.now)

# Change the column to not allow null
change_column :my_models, :date_column, :datetime, null: false

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