>Can any one explain me what is clustered and non clustered indexs?
>
>Mohammed

This is just a brief overview... Clustered indexes are the actual order the data is in stored in the table. A non-Clustered index simply has a pointer to the data on the page (if there is no clustered index).

Since a clustered index is the physical order of the table, you can only have one per table.

If you have a clustered index, any non-clustered indexes are built on top of that index. So, in order to get through the non-clustered index to the data, you have to traverse the non-clustered index, get what is called a 'clustering key', and then traverse the clustered index to find your data.

If you have SQL Bol, you might want to read all you can there about the two.