data model

database The product of the database design process which

aims to identify and organize the required data logically and

physically.

A data model says what information is to be contained in a

database, how the information will be used, and how the items

in the database will be related to each other.

For example, a data model might specify that a customer is

represented by a customer name and credit card number and a

product as a product code and price, and that there is a

one-to-many relation between a customer and a product.

It can be difficult to change a database layout once code has

been written and data inserted. A well thought-out data model

reduces the need for such changes. Data modelling enhances

application maintainability and future systems may re-use

parts of existing models, which should lower development

costs.

A data modelling language is a mathematical formalism with a

notation for describing data structures and a set of

operations used to manipulate and validate that data.

One of the most widely used methods for developing data models

is the entity-relationship model. The relational model is

the most widely used type of data model. Another example is

NIAM.

["Principles of Database and Knowledge-Base Systems",

J.D. Ullman, Volume I, Computer Science Press, 1988, p. 32].

(2000-06-24)