org.eclipse.osbp.dsl.examples.entity/models/Example06-persistence-inheritancebyclass.entitymodel

/**
 * Example for persistence with the "inheritance per class" strategy
 * 
 * The "Inheritance per class" strategy causes subclasses to share the database tables
 * of their parent classes. In order to be able to tell the types of the entries apart, a 
 * discriminator has to be used.
 * 
 * Thus, a single table is created that has the columns of all entities that share it (causing
 * a tradeoff between database size and access speed).
 * 
 * "inheritance per class" needs to be declared in the topmost entity that should share the
 * common table. The setting is then inherited by children.
 * 
 * The example below shows the declaration of custom values; inheritance per class
 * declarations have been added to sub-entities in order to override default values. This would
 * not have been necessary.
 * 
 */
 
package org.eclipse.osbp.entitydsl.samples.sample06 {

	entity Vehicle {
		inheritance per class {
			discriminatorColumn TYPE_DISCR_COLUMN;
			discriminatorType STRING;
			discriminatorValue VEH;
		}
		uuid String id ;
		var String name;
	}

	entity Bike extends Vehicle {
		inheritance per class {
			discriminatorValue BIKE;
		}
		var String[*] bikedescription;
		var int price;
	}
	
	entity Boat extends Vehicle {
		inheritance per class {
			discriminatorValue BOAT;
		}
		var String[*] boatdescription;
		var int price;
	}
	

}