Hi, Jared! On Dec 27, Jared Beck wrote: > On Wed, Dec 27, 2017 at 3:30 PM, Sergei Golubchik <s...@mariadb.org> wrote: > >> Any plans to implement partial indexes? > >> (https://www.postgresql.org/docs/10/static/indexes-partial.html) > > > > No such plans at the moment. > > What do you you need them for? > > I have used unique partial indexes to enforce business rules like > "Active users must have a unique phone number, but there may be any > number of inactive users with the same phone number" > > ``` > create unique index ix_active_phones > on users (phone) > where active = true > ;
That's a good use case. It's basically a "partial constraint", not partial index. In MariaDB (and in SQL standard) the way to achieve that would be to use a nullable column for active, and mark inactive users with NULL. Then you can create a unique index on (phone,active). Regards, Sergei Chief Architect MariaDB and secur...@mariadb.org _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
