PostgreSQL：如何更改表定义

Question

The problem: I'm searching for an alternative solution to change column definition in postgresql .

I would like to do something that is similar to the mysql solution:

ALTER TABLE table_name 
CHANGE [COLUMN] old_col_name new_col_name column_definition 

Is there a way to use CHANGE COLUMN similar to what I've described previously? Is there any way to easily change the column definition in postgres?

I'd like to use a similar method to my example because I'm building the alter query from code.

Answer 1

There is no direct equivalent to MySQL's CHANGE COLUMN clause in PostgreSQL. You'll need to specify the column definitions parts one by one. See documentation for ALTER TABLE . Fortunately you don't need to detect differences between old definition and new in typical cases, if the change is redundant PostgreSQL will just ignore it. eg ALTER COLUMN x DROP NOT NULL will still work when the column is already nullable.