A collection of normalized tables.
In the relational model, we use relations to hold information about the objects that we want to represent in the database. We represent a relation as a table in which the rows of the table correspond to individual records and the table columns correspond to attributes. Attributes can appear in any order and the relation will still be the same relation, and therefore convey the same meaning. For example, in the StayHome video rental company, the information on branches is represented by the Branch relation, with columns for attributes branchNo (the branch number), street, city, state, zipCode, and mgrStaffNo (the staffnumber corresponding to the manager of the branch).