inheritance in relational database

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hi
How i implement inheritance in tables on a relational database?
for example i have the members class that is a super class and it has only user name attribute.my child classes are:admin_users and other_users that derived from members super class.these child classes consists of password attribute
for that user.i want to know each work must be done: implement this hierarchy in one table in database or each class must has own table.
thanks a lot.

Posted 1-Sep-10 21:04pm

yekta_68

Updated 1-Sep-10 21:50pm

Dalek Dave

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Dalek Dave 2-Sep-10 3:50am

Edited for Grammar, Syntax, Spelling and Code Block Removal.

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Al-Farooque Shubho · Accepted Answer · 2010-09-01T21:15:00

Unfortunately, we still lack a true Object Oriented database, and, databases are still Relational. That's why we need Object Relational mapper (ORM) between the application and the database to do database operations.

But, you can implement the similar relationship in the database, that you have in your object design. That is, you can have a Members table with only {id,Name} fields. Then, you can have User table with a column {MemberId}, referring to the Id field of the Members table. The User table will also have another column UserType for identifying the user type which points to (Admin user, or, other user) another separate table UserType{Id, Type}.