Where does catalog store CHAR length ?

Started by phd9110about 22 years ago2 messages
#1phd9110
phd9110@cs.nchu.edu.tw

hi
the table pg_attribute have the attribute "attlen" , and this attribute will
store the attribute length. For example , when integer , this value will be 4.
But if attribute type is Char(xx), this value will be -1. This is because it
reference the bychar in pg_type table.

So, where is the Char() length information store ??
and what time will system check this string length constraint ?

thanks for your help!
Kao , Nchu Taiwan

#2Alvaro Herrera
alvherre@dcc.uchile.cl
In reply to: phd9110 (#1)
Re: Where does catalog store CHAR length ?

On Mon, Dec 01, 2003 at 06:31:56PM +0800, phd9110 wrote:

the table pg_attribute have the attribute "attlen" , and this attribute will
store the attribute length. For example , when integer , this value will be 4.
But if attribute type is Char(xx), this value will be -1. This is because it
reference the bychar in pg_type table.

So, where is the Char() length information store ??

atttypmod is the maximum length + 4.

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"El destino baraja y nosotros jugamos" (A. Schopenhauer)