Re: ALTER TABLE and dropping a column

Frank,

> ALTER TABLE foo DROP COLUMN bar;
>
> Is there a way to do that manually and safely, e.g. by manipulating
> pg_class or pg_attribute? I found a couple of threads about it dating
> from way back in summer 2000 and early 2001, but nothing conclusive.

At this time, I would strongly recommend one of two approaches:

If the table has multiple constraints and other dependant objects:
1. pg_dump the database.
2. Edit the table definition and the data for the table from the
pg_dump file.
3. Restore the database from pg_dump

If it doesn't:
1. Select the data for columns you want to keep into a new holding
table.
2. Drop and re-build the table with the correct columns.
3. Insert the data from the holding table into the re-build table.
4. Drop the holding table.

It's a pain, I know, but not nearly the pain you will suffer if you
start mucking with the system tables ...

-Josh

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