Re: Chante domain type - Postgres 9.2

On Sep 26, 2016, at 8:46 AM, Michael Sheaver <msheaver@me.com> wrote:

I have done some research after converting my database from MySQL 5.6 to PostgreSQL 9.6 (the best move I have ever made), and the consensus I found can be summed up as:

1.  Never, neve, never use VARCHAR or even CHAR

2. Always always, always use TEXT

Unless, that is, you have some kind of edge case. This may require a little work upfront, but it will save you from a TON of grief down the road.

On Sep 26, 2016, at 8:29 AM, Jan de Visser <jan@de-visser.net> wrote:

On 2016-09-26 1:15 AM, Gavin Flower wrote:

On 26/09/16 17:58, Patrick B wrote:

Hi guys,

I've got this domain:

   CREATE DOMAIN public.a_city
     AS character varying(80)
     COLLATE pg_catalog."default";


And I need to increase the type from character varying(80) to character varying(255).

How can I do that? didn't find info about it. I'm using Postgres 9.2

Thanks!
Patrick

Why not simply use the 'text' data type?

To change the data type on a column you can use:
ALTER [ COLUMN ] /column_name/ [ SET DATA ] TYPE /data_type/ [ COLLATE /collation/ ] [ USING /expression/ ]

see:
https://www.postgresql.org/docs/9.2/static/sql-altertable.html


Note that 9.5 is the latest version of pg, with 9.6 being released very soon!


Cheers,
Gavin

So I guess the answer to the question is:
- Find all occurrences of a_city
- Change the type of those columns to text (or varchar(80))
- Drop the domain
- Recreate with the proper definition. I agree with Gavin that text is a better choice. Experience has taught me that server side size constraint are more trouble than they're worth and that size constraints are better handled on the client side.
- Change the type of the columns back to the domain.





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