Relational Databases
An RBD is a set of ‘tuples’; each tuple represents a simple object with scalar attributes. Tuples are stored externally as records in a file and viewed conceptually as rows of a table, or geometrically as points in a multi-typed coordinate space.
Complex structured data types (and object instances) are decomposed or ‘normalized’ into simple parts or Second Normal Form (2NF): (no structured attributes or repeating groups are allowed).
For maintenance and reliability reasons, the design is further normalized (3NF): (There are no redundant or indirectly computable field values and all properties are stored in only one place.) [Ref: Sanders Ch. 3 and Appndx A.]
Other database types include object-oriented OODB’s, and object-relational ORDB’s. (next slide)