Record-Based Logical Models

Relational Model

The relational model was introduced in an academic paper by E.F.Codd in 1970 as a way to make database management systems more independent of any particular application.

The relational database model is based upon the conception of implementing the database with the mathematical set theory. In this model, data is collection of tables called Relation in the set theory. The tabular representation of data contains rows and columns in which rows represent set of attributes of individual entity and columns represent the attribute of entity.

Three key terms are used extensively in relational database models; relations, attributes, and domains. A relation is a table with columns and rows. The named columns of the relation are called attributes, and the domain is the set of values the attributes are allowed to take.

All relations in a relational database have to adhere to some basic rules to qualify as relations. First, the ordering of columns is immaterial in a table. Second, there can't be identical tuples or rows in a table. And third, each tuple will contain a single value for each of its attributes.

Components of the Relational Model

1. Collections of objects or relations that store the data.

2. A set of operators that can act on the relations to produce other relations.

3. Data integrity for accuracy and consistency.