Expressions: Type 1

In the Expression box in the Invoice validation group box you type an expression to validate a numerical field.

There are two types of expressions. Type 1 validates the current field in relation to other fields.

Type 1 can be:

  • A mathematical expression. Refers to the current field but does not name it.
  • A relational operator followed by a field name or arithmetic expression. Refers to the current field but does not name it.

Examples (assuming the current field is FieldA):

<=FieldB FieldA must be less than or equal to FieldB
>FieldC FieldA must be greater than FieldC
= FieldD + FieldE FieldA must be equal to the sum of FieldD and FieldE

If you omit the relational operator, the program assumes "=" by default.

Example (assuming the current field is FieldA):

FieldB+FieldC (The same as =FieldB+FieldC)

Type 1 expressions can always be rewritten as type 2 expressions. For example, these two expressions mean the same thing (assuming the current field is FieldA):

Type 1: =FieldB+FieldC

Type 2: FieldA=FieldB+FieldC