Subject create unique index vs alter table add unique()
Author Erik LaBianca
I recently found out something I didn't know, and am curious if it's
really 'as-designed' behavior. It certainly runs counter to my
experience with other dbms's.

If it's really as designed, I suggest adding a more explicit note that
the constraint is NOT created in the documentation for CREATE UNIQUE
INDEX. I'm using firebird classic on linux.

When creating an index using 'CREATE UNIQUE INDEX MYINDEX ON MYTABLE
(FIELDS)', the index is created, but it apparently doesn't add the
constraint to the relevant table limiting operations on the table data.
Is this actually useful for anything?

I did find that using 'ALTER TABLE MYTABLE ADD UNIQUE(FIELDS)' did what
I expected, but why aren't the two idioms synonyms?