>>>>> "barries" == barries <barries@stripped> writes:
barries> On Tue, Nov 21, 2000 at 08:47:00AM -0700, sasha@stripped wrote:
>> > UNIQUE ( person_id, ident_doc_type ) WHERE valid_to IS NULL
>> Monty - I think it is a good idea, and should not be too hard to do - you just
>> check the expr before you update the key, and check it again before doing a key
>> read - is there anything else involved, other than storing/retrieving the expr?
barries> Is this the start of computed function indexes (I hope)?
No; Computed index are in a sence easier to handle than this :)
The problems with computed index are:
- You can't use a standalone tool like myisamchk to check the table.
- It will be a problem for the optimizer to pattern-match the query
for when to use the index.