Single Table Inheritance

<p>Single table inheritance is a way to emulate <a href="/facts/Object-oriented/TxNMEcao">object-oriented</a> <a href="/facts/Inheritance_(object-oriented_programming)/a7R1xv8n">inheritance</a> in a <a href="/facts/Relational_database/pEKGmJLy">relational database</a>.  When <a href="/facts/Map_(mathematics)/FABF1l2f">mapping</a> from a <a href="/facts/Database/VYcpkevb">database</a> table to an object in an <a href="/facts/Object-oriented_language/TxNMEcao">object-oriented language</a>, a field in the database identifies what class in the <a href="/facts/Hierarchy/mYJyqFrG">hierarchy</a> the object belongs to. All fields of all the classes are stored in the same table, hence the name "Single Table Inheritance".   In <a href="/facts/Ruby_on_Rails/aG5P6uon">Ruby on Rails</a> the field in the table called 'type' identifies the name of the <a href="/facts/Class_(computer_science)/zvzkSAtE">class</a>.  In <a href="/facts/Hibernate_(Java)/7hHcgTkB">Hibernate (Java)</a> and <a href="/facts/Entity_Framework/20FoR2zr">Entity Framework</a> this pattern is called  Table-Per-Class-Hierarchy and Table-Per-Hierarchy (TPH) respectively., and the column containing the class name is called the Discriminator column.
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Single Table Inheritance open-in-new

Single Table Inheritance