context-var            A context variable. A temporary name that
                           you associate with a relation. You define
                           a context variable in a relation clause.
                           For more information see the entry on
                           Context Variables.

    on-error               The ON ERROR clause. Specifies host
                           language statement(s) to be performed
                           if an error occurs during the MODIFY
                           operation. For more information see the
                           entry on ON ERROR.

    statement              Any valid RDML or host language statement
                           to be executed within the MODIFY
                           operation. Use a semicolon (;) at the
                           end of each RDML, Pascal, or C statement.

    record-descr           A valid host language record descriptor
                           that matches all the fields of the
                           relation. Each field of the record
                           descriptor must match exactly the field
                           names and data types of the fields in the
                           Oracle Rdb relation referenced by the
                           context variable.