Synonyms

Tested on an Oracle 11 database.

You can use a synonym to create an alias for an object e.g. a table or view:

 

SQL> create synonym a for b

  2  /

 

Synonym created.

 

SQL> create public synonym x for y

  2  /

 

Synonym created.

SQL>
  

If the object does not exist, you do not get an error until you try to access it:

SQL> desc a

ERROR:

ORA-04043: object "SYSTEM"."B" does not exist

 

SQL> desc x

ERROR:

ORA-04043: object "SYSTEM"."Y" does not exist

 

SQL>

And you can even create a synonym for an object which belongs to a user who does not exist:

SQL> create synonym c for d.e;

 

Synonym created.

 

SQL> select count(*) from dba_users

  2  where username = 'D';

 

  COUNT(*)

----------

         0

 

1 row selected.

 

SQL> desc c

ERROR:

ORA-04043: object "D"."E" does not exist

 

SQL>