# Functions in a component rule

For example, the object **TotalQty** in your data is
the sum of all the **Qty** objects in your data; in a component rule for **TotalQty**,
you can use the SUM function to verify this relationship.

For example, the object **TotalQty** in your data is
the sum of all the **Qty** objects in your data; in a component rule for **TotalQty**,
you can use the SUM function to verify this relationship.