A Page Definition Queries is a dynamic SQL Where clause based on the values of the designated page name field for Data Driven Pages. Therefore, layers being defined must contain an attribute and appropriate values that can be matched to the designated page name field of the Data Driven Pages index layer. Page Definition Queries react to any change in attribute values in either the index layer field driving the Data Driven Page name or the field specified in the Page Definition Query dialog box. You may need to refresh Data Driven Pages to see any changes for the page currently being viewed.