DOMAIN usability - Mailing list pgsql-general

Hi  ,

I think one of the usage patterns of  DOMAINS is
to have size specifications and validity constraints
at one place for easy administration of Database.

Eg, instead of declaring email to be varchar(30) in
10s of tables  and putting a CHECK constraint for
presence of  '@'  we could declare

CREATE DOMAIN email_type varchar (30) CHECK ( value ~* '@') ;

And users could use "email_type" in our CREATE TABLEs .


There are two main issues (problems)

1. Suppose varchar(30) turns out to be too small oneday
    and we want to increase it to varchar(100)  , what do i do ?
    a)   Create a new domain ,
    b)  Apply all  the constraints  on new domain
    c)  Create new column in each of the tables and copy the old column
    d)  drop the old domain cascaded.

    any other more elegent method ?


2. Its difficult to see all the constraint defs on a domain .
    information_schema.domain_constriants does not have the
   definations just the names are present.

Regards
Mallah.