tableperconcreteclass

TablePerConcreteClass is a strategy used in object-relational mapping (ORM) to map each concrete class in an inheritance hierarchy to a separate table in a relational database. This approach is particularly useful when dealing with complex inheritance structures where each subclass has unique attributes that are not shared with other subclasses.

In TablePerConcreteClass, each concrete class is mapped to its own table, and the tables do not share any columns. This means that common attributes are duplicated across the tables, which can lead to redundancy. However, this redundancy can be beneficial in terms of query performance, as it avoids the need for complex joins.

One of the main advantages of TablePerConcreteClass is its simplicity. Since each table corresponds directly to a concrete class, the mapping is straightforward and easy to understand. This can make the schema more intuitive for developers who are familiar with the object-oriented model.

However, the duplication of common attributes can lead to increased storage requirements and potential data inconsistency issues. Additionally, if the common attributes need to be updated, it requires updating multiple tables, which can be cumbersome and error-prone.

TablePerConcreteClass is often used in scenarios where performance is critical, and the overhead of joins is deemed too high. It is also suitable for applications where the inheritance hierarchy is relatively shallow and the number of subclasses is limited.

In summary, TablePerConcreteClass is a mapping strategy that maps each concrete class to a separate table, avoiding the need for joins but introducing redundancy. It is best suited for scenarios where performance is a priority and the inheritance hierarchy is not overly complex.