CDO provides the following expressions:

    o  Value expressions-to calculate a value

    o  Conditional expressions-to represent a relationship between
       values

    o  Record selection expressions (RSE)-to state a condition for
       processing

    CDO stores expressions in a generic format, not as text, so that
    many products and applications can share the same expression.
    The product using the CDO expression calculates the value at run
    time.