OnlyOne function

Syntax

OnlyOne(fieldlist)

where fieldlist is an arbitrary-length list of fields in the form:

[recordname.]fieldname1 [, [recordname.]fieldname2] ...

Description

Use the OnlyOne function to check a list of fields and return True if one and only one of the fields has a value. If all of the fields are empty, or if more than one of the fields has a value, OnlyOne returns False. This function is used to validate that only one of a set of mutually exclusive fields has been given a value.

A blank character field, or a zero numeric value in a required numeric field is considered a Null value.

Example

You typically use OnlyOne as follows:

If OnlyOne(param_one, param_two)
   Then value_a = "y";
End-if;

Related Functions

Function	Description
All function	Checks to see if a field contains a value, or if all the fields in a list of fields contain values. If any of the fields is Null, then All returns False.
AllOrNone function	Checks if either all the field parameters have values, or none of them have values. Use this in examples where if the user fills in one field, she must fill in all the other related values.
None function	Checks that a field or list of fields have no value.
OnlyOneOrNone function	Checks if no more than one field in the set has a value. Use this in examples when a set of fields is both optional and mutually exclusive; that is, if the user can put a value into one field in a set of fields, or leave them all empty.