By default, specifies the user name of the process that invokes
 interactive SQL or runs a program.  Consider an application used
 by several people to record their sales.  The application
 identifies the sales person by assigning USER to a column in the
 table:

 EXEC SQL
 INSERT INTO SALES_LOG
         (DATE, AMOUNT, SALES_PERSON)
         VALUES
         (:SALE_DATE, :SALE_AMOUNT, USER)
 END-EXEC

 Sales people could then easily retrieve logs of their sales:

 SQL> SELECT * FROM SALES_LOG
 cont>   WHERE SALES_PERSON = USER;