If the value is One then a "1:1" relationship between the tables is established. If the value is More than one, then a "1:many" relationship is established. The relationship between the tables affects the method by which screen formats are designed. It determines the type of PJCs that can be created. (Refer to Access Routes and PJCs in the Developer Guide.)
Allowable values are:
Predeterfmined Join Column Development in the Developer Guide.