On Wed, 22 Jun 2016 10:20:38 +0000 Sameer Kumar <sameer.kumar@xxxxxxxxxx> wrote: > On Wed, Jun 22, 2016 at 6:08 PM Vlad Arkhipov <arhipov@xxxxxxxxxxxx> wrote: > > > I am running PostgreSQL 9.5. > > > > CREATE TABLE t (id BIGINT NOT NULL PRIMARY KEY, name TEXT); > > > > The constraint that the data must satisfy is `there is no more than 3 > > records with the same name`. > > > > I am not in control of queries that modify the table, so advisory locks > > can hardly be of help to me. > > > > Define a function which does a count of the rows and if count is 3 it > return false if count is less it returns true. An exclusion constraint might be a better solution. -- Bill Moran -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
