SAVEPOINT
 
 
  savepoints
  defining
 
 
  SAVEPOINT
  7
  SQL - Language Statements
 
 
  SAVEPOINT
  define a new savepoint within the current transaction
 
 
SAVEPOINT savepoint_name
 
 
  Description
  
   SAVEPOINT establishes a new savepoint within
   the current transaction.
  
  
   A savepoint is a special mark inside a transaction that allows all commands
   that are executed after it was established to be rolled back, restoring
   the transaction state to what it was at the time of the savepoint.
  
 
 
  Parameters
  
   
    savepoint_name
    
     
      The name to give to the new savepoint.
     
    
   
  
 
 
  Notes
  
   Use  to
   rollback to a savepoint.  Use 
   to destroy a savepoint, keeping
   the effects of commands executed after it was established.
  
  
   Savepoints can only be established when inside a transaction block.
   There can be multiple savepoints defined within a transaction.
  
 
 
  Examples
  
   To establish a savepoint and later undo the effects of all commands executed
   after it was established:
BEGIN;
    INSERT INTO table1 VALUES (1);
    SAVEPOINT my_savepoint;
    INSERT INTO table1 VALUES (2);
    ROLLBACK TO SAVEPOINT my_savepoint;
    INSERT INTO table1 VALUES (3);
COMMIT;
   The above transaction will insert the values 1 and 3, but not 2.
  
  
   To establish and later destroy a savepoint:
BEGIN;
    INSERT INTO table1 VALUES (3);
    SAVEPOINT my_savepoint;
    INSERT INTO table1 VALUES (4);
    RELEASE SAVEPOINT my_savepoint;
COMMIT;
   The above transaction will insert both 3 and 4.
  
 
 
  Compatibility
  
   SQL requires a savepoint to be destroyed automatically when another
   savepoint with the same name is established.  In
   PostgreSQL, the old savepoint is kept, though only the more
   recent one will be used when rolling back or releasing.  (Releasing the
   newer savepoint with RELEASE SAVEPOINT will cause the older one
   to again become accessible to ROLLBACK TO SAVEPOINT and
   RELEASE SAVEPOINT.) Otherwise, SAVEPOINT is
   fully SQL conforming.
  
 
 
  See Also