Comments inline: On 1/13/06, Sandeep Dubey <dubey.sandeep@xxxxxxxxx> wrote: > > > I am sorry I can't be more helpful. I don't really see this as problem, > to > > me it's more of an exemple of bad data. > > I am not sure if it is a bad data model. It's battle of normalization > - denormalization. The example given would appear to be denormalized. There is no candidate key to start with. I have a table Items. It's child is item_parts. Item can be made up of > 1 or may parts. So it is right to store in a table like item_parts. > okay? The example does not match what you were trying to do. You won't get much help here with an example like that. What you are trying to do requires 3 tables. ITEMS, PARTS, and an intersection table. If a a part can appear in more than 1 item, you can't store the PARTS data as a child table of ITEMS. Now if business asks give me the item that EXACTLY matches these parts > - no more no less, its a valid question too. Yes, it is. You just can't answer it in a reasonable manner with 1 table, or 2 tables. Answering that particular question will probably still require some imaginative SQL. -- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist