Table Inheritance

Only tables that are defined on named row types support table inheritance. Table inheritance is the property that allows a table to inherit the behavior (constraints, storage options, triggers) from the supertable above it in the table hierarchy. A table hierarchy is the relationship that you can define among tables in which subtables inherit the behavior of supertables. A table inheritance provides the following advantages:

• It encourages modular implementation of your data model.
• It ensures consistent reuse of schema components.
• It allows you to construct queries whose scope can be some or all of the tables in the table hierarchy.

In a table hierarchy, a subtable automatically inherits the following properties from its supertable:

• All constraint definitions (primary key, unique, and referential constraints)
• Storage option
• All triggers
• Indexes
• Access method