Re: pg_get_triggerdef in pg_dump

Alvaro Herrera wrote:

>On Wed, Jun 18, 2003 at 12:59:36PM +0200, Andreas Pflug wrote:
>
>
>
>>What I need again and again, is changing the size of a column (rarely
>>the type). For pgsql, I'd have to drop the column, and need to recreate
>>all views. For MSSQL, it won't matter if the column is dropped/recreated
>>or just resized, the view won't notice until it's used again.
>>
>>
>
>If that's what you need you can always change the system catalogs
>manually. For CHAR(n) and VARCHAR(n) you change pg_attribute.atttypmod
>to (n+4). For NUMERIC(n,m) it's something like (n<<16) + m + 4 or maybe
>(m<<16) + n + 4, don't remember right now.
>
>Be sure to check that your data is in a safe place before you do this,
>and double check before you commit the transaction if you do it
>manually.
>
>
>
Hm, you're right, 'thou I wouldn't recommend this to the average user,
and wonder if this will be possible for all future pgsql versions too.
I'm considering adding safe support for this type of column change to
pgAdmin3.
There might be other cases of legal direct change of system catalog
entries, e,g. varchar to text, if they all are only names for internally
identical data structures. Can you tell which datatypes may be legally
interchanged?

Regards,
Andreas