Object Ownership v/s Parsed Query

Hi,

I wish to know how execution plan is identified. Specifically, consider the following scenario:

If a table, say MyTab is created by users A, B and C within their respective default tablespaces, A.MyTab and C.MyTab having same structures but b.MyTab have different structure. Now if user C issues following statements -

Select * from A.MyTab
Select * from B.MyTab
Select * from MyTab

• How are the queries parsed?
• How is their execution plan identified?
• Will exec plan be different for all?
• If it is different for all, isn't it always a better practice to qualify the table name with owner name within front-end code?
• What about cost of query and reusability of the query once it is parsed? In what cases same parsed one could be used?

Excuse me if i am sounding a novice.

I would appreciate if anybody could answer my queries here.

Thanks In Advance.

S. Received on Wed Aug 01 2001 - 12:24:34 CDT