资料来源 : Free On-Line Dictionary of Computing

data model
     
         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)