Redshift-如何删除NOT NULL约束? [英] Redshift - How to remove NOT NULL constraint?

问题描述

由于Redshift不支持ALTER COLUMN，所以我想知道是否有可能从Redshift的列中删除NOT NULL约束.

Since Redshift does not support ALTER COLUMN, I would like to know if it's possible to remove the NOT NULL constraints from columns in Redshift.

推荐答案

您不能更改表.

有另一种方法.您可以创建一个具有NULL约束的新列.将值从旧列复制到新列，然后删除旧列.

There is an alternative approach. You can create a new column with NULL constraint. Copy the values from your old column to this new column and then drop the old column.

类似这样的东西:

ALTER TABLE table1 ADD COLUMN somecolumn (definition as per your reqm);
UPDATE table1 SET somecolumn = oldcolumn;
ALTER TABLE table1 DROP COLUMN oldcolumn;
ALTER TABLE table1 RENAME COLUMN somecolumn TO oldcolumn;

这篇关于Redshift-如何删除NOT NULL约束?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！