Hi,
I have 2 tables called CAL, Emp.
Emp_id is primary key in emp table.
Cal.Emp_id is foreign key.
But i don't have index on cal.emp_id.

I read the below statement id Doc:

It is highly recommended that an index be created if the Foreign Key column is used in joining, or often used in a WHERE clause. Otherwise a table level lock will be placed on the parent table.

How the above statement exatly effect on the database.
user entering the data in cal table from web interface and doing commit imm. So give me some info on this. Thanks.