Re: Converting char to varchar automatically

This query might work for you, but double check all result statements first.

SELECT 'ALTER TABLE ' || quote_ident(n.nspname) || '.' ||
quote_ident(c.relname)
|| ' ALTER COLUMN ' || quote_ident(a.attname) || ' TYPE varchar;'
FROM pg_class c
JOIN pg_namespace n ON n.oid = c.relnamespace
JOIN pg_attribute a ON a.attrelid = c.oid
JOIN pg_type t ON t.oid = a.atttypid
WHERE t.typname = 'char'
AND n.nspname <> 'pg_catalog';

On Mon, Oct 6, 2014 at 6:29 AM, Andrus <kobruleht2(at)hot(dot)ee> wrote:

> Database contains about 300 tables.
> Most of them contain columns of char(n) type.
>
> How to convert all those columns to varchar automatically ?
>
> Is it possible to run some update commands in system tables for this ?
> Or is it possible to create pgsql script which creates dynamically alter
> table alter column commands and PERFORMs them ?
>
> Any tables have primary keys with char(n) columns and foreign keys on
> them. Foreign keys are deferrable and initially immediate.
> Will foreign keys allow to perform such alter table alter column commands ?
> Or is there better way.
>
> Andrus.
>

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*Melvin Davidson*
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wish to share my fantasy is entirely up to you.