On 3/4/23 05:51, Peter J. Holzer wrote:
On 2023-03-04 02:34:02 -0600, Ron wrote:
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...
Just curious: Which RDBMS was that?
Rdb/VMS (the DEC product for OpenVMS, which has been owned by Oracle for the
past 25 years).
Speaking of foreign key constraints: Neither Oracle nor PostgreSQL
automatically add an index on a foreign key. That bit me hard back in
the day ...
Us too. (Well, the developer, from before I arrived.)
--
Born in Arizona, moved to Babylonia.
