6. Using JoinDefs in QBF : Join Types : Master/Detail JoinDefs
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Master/Detail JoinDefs
When QBF executes a query in which the query target is a Master/Detail JoinDef, the data appears to have come from two tables--one that is a set of all the master tables and one that is a set of all the detail tables. The master table information is displayed as simple fields, and the detail table information is displayed as either a table field or simple fields.
If there are no detail records for the master record, QBF still retrieves the master record. Thus, QBF retrieves and displays master records even if there are no corresponding identical values in the detail table join column.
A JoinDef can contain several Master/Master joins, but only one Master/Detail join. You can include multiple detail tables relative to the master table(s) in a Master/Detail JoinDef by joining them to the detail table in the Master/Detail join. For example, the second figure in this chapter shows a Master/Detail relationship combining only one pair of tables. This figure also shows several pairs joined together with Master/Master joins and several Detail tables joined to each other. For illustrations of a Master/Master JoinDef and resulting data, see the preceding two figures.