Object staff

For instance, the attribute name of the object Staff is a monovalued attribute, whereas the attribute address is a multivalued attribute.

For instance, the object Staff inherits all the information of the object Person.

An object, say O, is represented as O([[Delta].sub.O]), where [[Delta].sub.O] is the type of the object; e.g., the object Staff is defined as Staff([[Id.sub.staff] : allID;surname : string;{name : string};salary : integer;{Drives : Car}{Child : Person}; {laboratory: Laboratory}]) where

Also, Staff-- name is a vertical path because name is a part of the type of the object Staff.

This local dependency is validated on every single instance of the object Staff. Since there are no two instances of Staff that have the same object identifier, the local dependency is a global dependency.

For instance, to compute the set of all instances of the object Project of the database in Table I, i.e., [Psi][Project]), we need to consider all the instances of the object Staff within the database and later project them according to the path [path.sub.project](Staff) = Staff--Laboratory.

Since the object Staff of Figure 2 has another path, which is Staff--Laboratory--date, then this path also induces additional (object) interpretations, defined as follows:

The set of all possible interpretations of the object Staff is defined by the different possible interpretations of the paths that the object Staff contains.

In the case of the object Staff, its model will involve all the possible semantics of its two paths, Staff--Laboratory--Project-report and Staff--Laboratory--date, i.e., all possible combinations of the sets [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

Assume that the user's interpretation of the object Staff contains the following GD-constraints (Staff, Project) [right arrow] {report} and (Project, report) [right arrow] {date}.

Now consider the remaining GD-constraint of the object Staff, i.e.

In the above example, on the normalization of the object Staff, two restructuring operations were applied, and these cover all possible transformations that can be used to normalize an object.