Catalog field contents

Attributes of a hierarchical catalog that have the Use property set to For item contain NULL values in the records that are groups. Similarly, those attributes that have the Use property set to For folder contain NULL in the records that are catalog items. Keep this in mind while writing queries to catalogs.

Example:

SELECT
	Items.Description, 
	Items.IsFolder, 
	Items.StockNumber, 
	CASE 
		WHEN (Items.StockNumber) IS NULL 
			THEN "NULL" 
		ELSE "NOT NULL" 
	END 
FROM 
	Catalog.Items AS Items

Result:

This example shows that, for all the group records, the value of the StockNumber attribute contains NULL.