Learning objectives
Explain the features of a relational database (tables, records, fields, and the primary, foreign and composite keys that link tables), its benefits such as integrity, reduced redundancy, concurrency control and security, and its limitations with big, unstructured or hierarchical data, rigid schemas and the object-relational mismatch
Describe conceptual, logical and physical schemas, and choose a data type for each field, explaining how a wrong choice damages consistency, integrity or performance
Construct entity relationship diagrams that show entities, attributes, relationships, cardinality and modality, and resolve a many-to-many relationship with a linking entity
Construct related tables with correctly chosen primary, foreign, composite and concatenated keys
Explain first, second and third normal form in terms of atomic values, partial dependencies and transitive dependencies, and normalize a data set to 3NF for a scenario such as a library, hospital, school or online shop, removing insertion, update and deletion anomalies
Evaluate denormalizing a database for a read-heavy application, weighing faster queries against duplicated data and the risk of inconsistent updates
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