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Qualifying a Relation

You can also use a QDR to qualify a relation (which is really a special kind of variable).

Suppose the region.district relation is dimensioned by district. When you qualify district with the value Seattle, then the value of the expression is the value of the relation for Seattle. Because the QDR specifies one value of district, the expression has a single–cell result.

The definition of region.district is as follows.

DEFINE region.district RELATION region <district>
LD The region for each district

The following statement displays the value WEST.

SHOW region.district(district 'Seattle')