DataPlay is a query tool that encourages a trial-and-error approach to query specification. DataPlay uses a graphical query language to make a particularly challenging query specification task-quantification-easier. It constrains the relational data model to enable the presentation of non-answers, in addition to answers, to aid query interpretation. Two novel features of DataPlay are suggesting semantic variations to a query and correcting queries by example. The authors introduce DataPlay as a sophisticated query specification tool and demonstrate its unique interaction models.