Authorization for Supertypes and Subtypes

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A supertype is a "constellation" of data in which the common attributes are defined as the supertype (or generalization), with variable additions (or specializations) for the subtypes.

For example, if Person is the supertype, Staff and Guide are possible subtypes.

Authorization is defined on the tables and columns defined in the Tables window of the Definer. Whether a table is part of a subtype tree (or constellation) is irrelevant. However, you must bear the following in mind:

The subtype indicator columns are included in the supertype tables. This means that you can also give rights on these subtype indicator columns.

The primary-key columns of the supertype are shown in all subtype tables. Although it is possible to define different rights for these columns in super- and sub-type tables, it is only useful to define it in the uppermost supertype table. Conceptually these columns are considered to be the same in the whole subtype constellation: defining authorization for primary key columns in subtypes is ignored.

Conditions on the rights on subtype tables and their columns can also contain columns of their supertype(s).

See Also:

How INSERT Statements are Handled

How DELETE Statements are Handled

How UPDATE Statements are Handled