Alters a synonym definition.

1  –  Environment

    You can use the ALTER SYNONYM statement:

    o  In interactive SQL

    o  Embedded in host language programs

    o  As part of a procedure in an SQL module

    o  In dynamic SQL as a statement to be dynamically executed

2  –  Format

  ALTER SYNONYM <synonym-name> -+----------------------+-+
                                +-> FOR <object-name> -+ |
  +------------------------------------------------------+
  ++-------------------------------+--------------------->
   +-> COMMENT IS -+-> 'string' -+-+
                   +----- / <----+

3  –  Arguments

3.1  –  COMMENT IS string

    This clause can be used to add several lines of comment to the
    synonym object. The SHOW SYNONYM statement displays the comment.

    This clause is equivalent to the COMMENT ON SYNONYM statement.

3.2  –  FOR object-name

    You may change the synonym to reference a different database
    object; however, it must be of the same type. Oracle Rdb assumes
    that the object has the same or similar characteristics as
    the referenced object. The referenced object must exist in the
    database.

3.3  –  synonym-name

    The name of an existing synonym you want to alter.

4  –  Examples

    Example 1: Adding a Comment

    SQL> ALTER SYNONYM CASH
    cont>   COMMENT IS 'use a different name to avoid confusion with'
    cont>   /          'the domain MONEY';

    Example 2: Using Multiple Synonyms and Changing the Referenced
    Table Using ALTER

    The following example uses a synonym to reference a table. Later
    an empty version of the table can be created and the synonym
    altered to reference this new table. Although similar to using a
    view definition, the use of synonyms avoid the usage locking of
    a view. That is, to drop and create a new view requires that no
    other user references that view, however, the alter synonym does
    not require exclusive access to the table.

    SQL> CREATE TABLE t_employees_0001 (...);
    SQL> CREATE SYNONYM employees FOR t_employees_0001;
    SQL> CREATE SYNONYM emps FOR employees;
    SQL> CREATE TABLE t_employees_0002 LIKE t_employees_0001;
    SQL> ALTER SYNONYM employees FOR t_employees_0002;