Is this a bug? I create a "unique" index, directly but it doesn't add a unique constraint. Add a unique constraint and it adds the index and the constraint. (pg version 9.4.5 on fedora 22, but also occurs in other versions). Functionally I can't see a difference. mydb=# create table test_table ( f1 bigint, f2 bigint); CREATE TABLE mydb=# create unique index test_table_un on test_table (f1, f2); CREATE INDEX mydb=# \d test_table Table "public.test_table" Column | Type | Modifiers --------+--------+----------- f1 | bigint | f2 | bigint | Indexes: "test_table_un" UNIQUE, btree (f1, f2) mydb=# select conindid, contype, conname from pg_constraint where conname like 'test_table%'; conindid | contype | conname ----------+---------+--------- (0 rows) -- -------------------------------------------------------------------------- mydb=# drop table test_table; DROP TABLE mydb=# create table test_table ( f1 bigint, f2 bigint); CREATE TABLE mydb=# alter table test_table add constraint test_table_un unique (f1,f2); ALTER TABLE mydb=# \d test_table Table "public.test_table" Column | Type | Modifiers --------+--------+----------- f1 | bigint | f2 | bigint | Indexes: "test_table_un" UNIQUE CONSTRAINT, btree (f1, f2) mydb=# select conindid, contype, conname from pg_constraint where conname like 'test_table%'; conindid | contype | conname ----------+---------+--------------- 4284073 | u | test_table_un (1 row) mydb=# -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general