Re: determine sequence name for a serial

# CREATE OR REPLACE FUNCTION get_default_value (text, text, text) RETURNS text AS '
# SELECT adsrc
# FROM pg_attrdef, pg_class, pg_namespace, pg_attribute
# WHERE
# adrelid = pg_class.oid AND
# pg_class.relnamespace = pg_namespace.oid AND
# pg_attribute.attnum = pg_attrdef.adnum AND
# pg_attribute.attrelid = pg_class.oid AND
# pg_namespace.nspname = $1 AND
# pg_class.relname = $2 AND
# pg_attribute.attname = $3;
# ' language sql;

As per Tom's mention of pg_depend, here's something that seems to do
the trick for the time being, assuming the column is a serial:

-- get_sequence(schema_name, table_name, column_name)

CREATE OR REPLACE FUNCTION get_sequence (text, text, text) RETURNS
text AS '
SELECT seq.relname::text
FROM pg_class src, pg_class seq, pg_namespace, pg_attribute,
pg_depend
WHERE
pg_depend.refobjsubid = pg_attribute.attnum AND
pg_depend.refobjid = src.oid AND
seq.oid = pg_depend.objid AND
src.relnamespace = pg_namespace.oid AND
pg_attribute.attrelid = src.oid AND
pg_namespace.nspname = $1 AND
src.relname = $2 AND
pg_attribute.attname = $3;
' language sql;

--
Jonathan Daugherty
http://www.cprogrammer.org