hello,
everyone!
 I want to know how postgresql remain its unique index unique after 
i have change it.For example:
 create table human(age int,name char(2));
then in the pg_attribute catalog the unique index pg_attribute_relid_attnum_index will
use relid of 'human'and attnum of age to create a index tuple for attribute:age,which is a unique index tuple for a tuple which describe age in pg_attribute,and i do:
 alter table human rename age to birthdate;
then in the unique index pg_attribute_relid_attnum_index will appear two index tuple 
which keys are relid of 'human' and attnum:1 to describe age ,but there is no error happening!!!!So i am interested in the method of remain the dynamic index very much.
 would you please tell how postgres do it and the src of this? 
thanks :) 
 
　　　　　　　　致
礼！
     
　　　　　　　　庄继锋
　　　　　　　　zhuangjifeng@263.net
　　　　　　　　　　2004-04-29