Assessing Information Quality for the Composite Relational Operation Join

Information plays an increasingly important role in strategic decision-making processes within businesses. Therefore, information quality and its assessment have become critical subjects for information products delivered to information consumers. Commonly, the information product provided to consumers is the output of queries in relational databases. The queries typically consist of one or more primitive relational algebra operations. Previous research has addressed the measurement of important quality attributes of the output of primitive relational algebra operations such as selection, projection, and Cartesian product. In this paper, we present a methodology to measure the quality profile of the output of the relational operation join, that is one of the most widely used composite operation. Different types of join operations are identified based on the attributes that participate in the join condition and the output quality profile for each of these types of the join operation is derived. Examples are provided to highlight the differences between the quality profile of the input relations and those of the output of the join operation.