DSXchange

Hi,
Can a column in a composite primary key be a null? we have a primary key with combination of 2 key columns.In those 2 key columns , can anyone be null?
Database is DB29.Does it accept? Any ideas.

Thanks

No.

No.

(having some transmission difficulties here - moderator, please remove)

All primary key columns in DB2 tables must be NOT NULL.

Re-design the target table. Or use a dedicated default value.

What does it really mean that you want to make part of a key unknown? Ponder on that for a while.

Thanks Ray..

Hi,
I got small doubt.If a key is specified on a column, Does it mean that it is indexed as a default? And if we create index on a column, does it mean that its a key?
I appreciate any clarifications..
Thanks

No. But usually indices are created on keys for faster updates and retrievals.

The vice versa is also not important, i.e, if an index is set on a column, it does'nt mean it is a key.

Thanks Brian..But i want to know as key is created on a column, is it indexed as well? or should we explicitly create an index on that key column.

Thanks

Indices need to be created explicitly, so yes, create them explicitly.

Thanks for the clarification..Really this DSXchange is helping a lot..

Note that the answer given relates to DB2. Some databases do automatically create an index on the primary key (though not on its individual columns).

Thanks Ray for pointing that..