Table Inheritance In Microsoft Dynamics Ax 2012

Table Inheritance :

• A table can extend from or derive from another table. Each table has the SupportInheritance property and the Extends property, which together control table inheritance.
• The default for each new table is to implicitly extend from the Common table. The extension from the Common table cannot be set or seen in the Extends property. A variable that is declared of a specific table also implicitly inherits methods from the xRecord class.
• In the terminology for table inheritance, we say that the derived table extends its base table. But we never use the terms parent or child to explain tables in an inheritance relationship. The terms parent and child can be used to describe foreign key relationships between tables.
• In Microsoft Dynamics AX, a table can inherit from another table. The AOT node for each table has the Extends property which you can use to derive your table from a table that you specify. 

Table inheritance is mainly controlled by the following properties:

1. SupportInheritance – specifies if a table is a part of a hierarchy.
2. InstanceRelationType – specifies the field that is used as a type discriminator. TableIds of concrete types are used as values of the InstanceRelationType field.
3. Abstact – specifies if a table is abstract. Tables without derived tables cannot be abstract.
4. Extends – specifies table’s parent.