Disjunctive predicates are those that have an 'OR' in them.  They are a bit
more difficult to optimize than simple and conjunctive predicates because
whenever any term in a conjunctive predicate is false, the row is excluded,
and therefore processing need not continue; whereas for disjunctive
predicates, both sides of the 'OR' must be false in order to exclude a row.

Some other predicates are really disjunctive predicates, IN predicates, for
example.  They can cause performance on some systems to bottom out because
often the conjunctive part of the query is executed many, many times--once
for each element in the IN list.

On Jan 30, 11:07 am, "Roy Hann" <specia...@processed.almost.meat>
wrote:

I think the terminology is only used with db2 for z/os. Anyhow, I
googled and found:

http://tinyurl.com/2bhgp4

To me it looks like Conjunctive Normal Form

/Lennart