|
Some databases will create a unique index for you when you create a primary key. Oracle will create one, but only if you haven’t already done that. Postgres will ALWAYS create a unique index based on the primary key – so you should never do that as well, or the db will have to maintain two identical indexes. (When we migrated our db design from Oracle we ended up with lots of duplicate indexes). SQL> Select * from pg_indexes order by schemaname, tablename; Phil Horder Database Mechanic Thales Land and Air Systems Horizon House, Throop Road, Templecombe, Somerset, BA8 0DH, UK Tel: +44 (0) 1963 37 2041 Email:
phil.horder@xxxxxxxxxxxxxxxxxx Please consider the environment before printing a hard copy of this email. The information contained in this e-mail is confidential. It is intended only for the stated addressee(s) and access to it by any other
person is unauthorised. If you are not an addressee, you must not disclose, copy, circulate or in any other way use or rely on the information contained in this e-mail. Such unauthorised use may be unlawful. If you have received this e-mail in error, please
inform us immediately on +44 (0)1963 370511 and delete it and all copies from your system. Thales UK Limited. A company registered in England and Wales. Registered Office: 350 Longwater Avenue, Green Park, Reading,
RG2 6GF. Registered Number: 868273 From: Thomas Poty [mailto:thomas.poty@xxxxxxxxx]
Hi all, I am migrating fromMySQL to Postgresql 9.6. In MySQL a "show create table" gives me : So, In PostgreSQL, does it make sense to create a primary key AND a unique index based on the same columns? Is PostgreSQL smart enough to use the unique index created for the primary key. I know PostgreSQL can be based on a unique index to create a primary key but I also know it is possible to create several indexes on the same columns with the same order. Thanks Thomas |
