class-table-inheritance

Suppose you were setting up a database to store crash test data of various vehicles. You want to store data of crash tests for speedboats, cars, and go-karts. You could create three separate tables: SpeedboatTests, CarTests, and GokartTests. But a lot of your columns are going to be the same in each table (for example, the employee id of the person who performed the test, the direction of the collision (front, side, rear), etc.). However, plenty of columns will be different, so you don't want to just put all of the test data in a single table because you'll have quite a few columns that will

Much asked on SO and around the web with regards to ZF2 with Doctrine 2 and using Discriminators is: how do you not declare all child Entities on the parent Entity? Especially when you have multiple modules? The short answer is : do not declare a discriminatorMap . Doctrine will handle it for you. The longer answer is below. A popular article on how to be able to declare your child Entities, on the children Entities, instead of the parent, is this one . However, Doctrine 2 has changed somewhat since it was written, e.g. the AnnotationWriter no longer exists. There, however, is a simpler way,

com.something.SuperClass: @Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public abstract class SuperClass implements Serializable { private static final long serialVersionUID = -695503064509648117L; long confirmationCode; @Id @GeneratedValue(strategy = GenerationType.AUTO) // Causes exception!!! public long getConfirmationCode() { return confirmationCode; } public void setConfirmationCode(long confirmationCode) { this.confirmationCode = confirmationCode; } } com.something.SubClass: @Entity public abstract class Subclass extends SuperClass { private static final long

My question is regarding Inheritance modeling in Relational Database Systems. I have canonical data model and in that I have some fields related to pricing of product inheriting certain attributes from product table and I want to model this inheritance in MySQL relational database and so, "How can we do Inheritance Modeling in Relational Databases ?" Thanks. Martin Fowler discusses this extensively in his book Patterns of Enterprise Application Architecture book. Get this book and look into: Single Table Inheritance Class Table Inheritance Concrete Table Inheritance The Website should give you