Uniqueness of Database Object Names
The database catalog in your database contains one row for each object (constraint, default, log, rule, stored procedure, etc.) created within a database. Because the DBMS enforces certain rules to ensure that objects have unique names, you must take care when naming objects.
When you name database objects in a database diagram or table diagram, you will be alerted if the name you choose is already used by another object. There are three possible outcomes when you name an object:
You choose a duplicate name detected by the Visual Database Tools.
In this case, you receive an error as soon as you try to name the object.You choose a duplicate name detected by the DBMS.
In this case, the Visual Database Tools initially accept the name, but the DBMS rejects the name when you try to save the object to the database; you receive an error.You choose a unique name.
In this case, you receive no error.