Hello,
Create a view as described @
http://www.postgresql.org/message-id/flat/3C055B7E.BB52F0F1@but.auc.dk#3C055B7E.BB52F0F1@but.auc.dk
create view my_tbldescription as
select
u.usename, t.typname AS tblname,
a.attname, a.atttypid, n.typname AS atttypname,
int4larger(a.attlen, a.atttypmod - 4) AS atttyplen,
a.attnotnull, a.attnum
from pg_user u, pg_type t, pg_attribute a, pg_type n
where u.usesysid = t.typowner
and t.typrelid = a.attrelid and t.typtype = 'c' and not (t.typname ~* 'pg_')
and n.typelem = a.atttypid
and substr(n.typname, 1, 1) = '_'
and a.attnum > 0 ;
And then create functions using that view.
create or replace function table_exists (tbl varchar) returns boolean AS $$
DECLARE
x integer;
BEGIN
Execute 'select count(*) from my_tbldescription where tblname=$1' into x using tbl;
if (x>0)
then
RETURN TRUE;
else
RETURN FALSE;
end if;
END;
$$ LANGUAGE plpgsql;
create or replace function column_exists (col varchar) returns boolean AS $$
DECLARE
x integer;
BEGIN
Execute 'select count(*) from my_tbldescription where attname=$1' into x using col;
if (x>0)
then
RETURN TRUE;
else
RETURN FALSE;
end if;
END;
Regards
Sameer
