Appendix B
Page 505

Example B-5

DDL Extract of Table to Store Parts of a Calculation Rule or
Formula

CREATE TABLE RULE_ELEMENTS
( RULE#  NUMBER
  CONSTRAINT rule_element_rule# REFERENCES rules
, step#  NUMBER  NOT NULL
, OP     CHAR(1) NOT NULL
  CONSTRAINT rule_element_op CHECK (OP IN ('+', '-', '*', '/', '%'))
, type   CHAR(1) NOT NULL
  CONSTRAINT rule_element_type CHECK (type IN ('literal', 'column'))
, literal NUMBER
, CONSTRAINT rule_element_literal CHECK
   (   (type  = 'literal' AND literal IS NOT NULL)
    or (type <> 'literal' AND literal IS     NULL))
, colname VARCHAR2(30)
, CONSTRAINT rule_element_colname CHECK
   (   (type  = 'column' AND colname IS NOT NULL)
    OR (type <> 'column' AND colname IS     NULL))
, CONSTRAINT rule_element_pk PRIMARY KEY (rule#, step#)
);