Class Table Inheritance Design Pattern

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What is the Class Table Inheritance Pattern?

The Class Table Inheritance pattern is an Object-Relational Structural Pattern used in Enterprise Application Architecture.

Since relational databases do not natively support inheritance, this pattern represents an inheritance hierarchy of classes by mapping one database table for each class in the hierarchy.

How Class Table Inheritance Works

Each class in your domain model maps directly to its own database table containing only the fields unique to that class:

• Player Class (Superclass): Maps to the players table (stores name).
• Footballer Class: Maps to the footballers table (stores club).
• Cricketer Class: Maps to the cricketers table (stores batting_average).
• Bowler Class: Maps to the bowlers table (stores bowling_average).

Linking Rows Across Tables

To link corresponding records across parent and child tables, a common Primary Key (foreign key pointing to parent table) is used:

• Saving Data: An instance of a child class requires inserting rows into both the parent table and the child table.
• Reading Data: Querying full object details requires joining the parent and child tables using their shared primary key.

Recommended Tutorials from Ram N Java

• Single Table Inheritance Design Pattern Demystified
• Java Inheritance Example: Child to Parent Relationship | Java Tutorial
• Spring bean configuration for inheritance [Override base bean value] | Spring Tutorial

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Class Table Inheritance Design Pattern