Organisations need to handle data with well-designed databases that minimise errors through updating, deletion and insertion, avoiding redundancies and providing ready retrieval of data in flexible forms adaptable to changing user needs. Relational Databases offer concepts in the development of a database from the listing of business requirements, through entity relationship diagramming, schema formation, and the evaluation of the effectiveness of a schema with concepts of functional dependency and normalisation. Following MC304, this unit builds on the underlying theoretical perspectives required to understand the design and management of databases using commercial software, relational algebra and the use SQL statements. Such operational concepts provide career-specific pathways for MCS graduates to develop relational databases for development and commercial organisations in Papua New Guinea.