Relational Database

Database Design

“The Entity-Relationship Data Model” begins with a high-level notation for expressing database designs, called the entity-relationship model. We introduce in “The Relational Data Model” the relational model, which is the model used by the most widely adopted DBMS's,

Boyce-Codd Normal Form

The objective of decomposition is to replace a relation by several that do not exhibit anomalies. There is, it turns out, a simple condition under which the anomalies discussed above can be guaranteed not to exist. This condition is called Boyce-Codd

Decomposition into BCNF

By frequently selecting appropriate decompositions, we can break any relation schema into a collection of subsets of its attributes with the following important properties:

Representing Other Type Constructors

Above and beyond record structures and sets, an ODL class definition could use Bag, List, Array, or Dictionary to construct values. To represent a bag (multiset), in which a single object can be a member of the bag n times, we cannot simply introduce into a relation n the

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