What Is Meant by the Closure of a Set of Functional Dependencies? A functional dependency is a one-way dependency between two attributes at any given time. For a unique attribute of value A there is one value of the attribute B associated with it through the relation. Even if the values for the attribute change, there …

Insertion, Deletion, and Modification Anomalies Are Considered Bad An insertion anomaly is a situation that arises when one is prevented from inserting data into a relation because the complete primary key is not available. No part of a primary key can be null. Harrington (2009) points out that insertion anomalies …

Different Parameter Types in Database Cost Functions and Their Information Storage The cost function is part of the query cost optimization module of the database management system. Elmasri & Navathe (2015) indicate that the optimizer heuristic rules or query transformations are not the only dependencies used for cost …