varchar_transform

Started by Mohsen SMalmost 12 years ago2 messages
#1Mohsen SM
mohsensoodkhah@gmail.com

when did use varchar_transform function?
src/backend/uitls/adt/varchar.c.

#2Robert Haas
robertmhaas@gmail.com
In reply to: Mohsen SM (#1)
Re: varchar_transform

On Mon, Feb 24, 2014 at 2:11 AM, Mohsen SM <mohsensoodkhah@gmail.com> wrote:

when did use varchar_transform function?
src/backend/uitls/adt/varchar.c.

The main point of that machinery is that if you do something like
ALTER TABLE zot ALTER COLUMN thunk SET DATA TYPE varchar(30) on a
column that is currently varchar(20), it won't feel obliged to rewrite
the table. That function lets it figure out that anything that's a
valid varchar(20) value is also a valid varchar(30) value.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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