On 3/4/23 02:03, Peter J. Holzer wrote:
[snip]
> So your plan is to create a unique constraint (backed by a unique
> index) and then to drop the index and keep the constraint?
>
> That doesn't work. A unique constraint can't exist without a (unique)
> index. Think about it: With a unique constraint PostgreSQL needs to
> check for every insert whether the value already exists in the table.
> Without an index this would mean a full table scan.
I cut my teeth on an RDBMS which didn't automagically create a backing
index. You had to do it yourself...
(Autocommit and the default transaction mode not being SERIALIZABLE were
also a shock when I started using other systems.)
--
Born in Arizona, moved to Babylonia.
