Question

Today I reviewed postgreSQL wiki and I found it is a ORDBMS (object-relational database management system), so I want to know is there any benefits for using postgreSql (RDBMS) behind the JPA (hibernate, eclipselink, ….) instead of a RDBMS (Mysql, …) for performance issues or not?

As you know JPA use ORM and use JQL (java query language)

Regards

Answer 1

Object-Relational data is defined as structured data, which is user defined types in the database.

OR data types include:

• Structs – structured types
• Arrays – array types

These types are defined differently in each database, in Oracle they are OBJECT types, VARRAY types, and NESTED TABLE, and REF types.

JDBC standardizes access to OR data types using the Struct, Array and Ref interfaces.

With OR data-types you can have more complex database schemas, such as a TABLE of Employee_Type that has a Varray of Phone_Types and a Ref to it manager.

JPA does not have any direct support for mapping OR data-types, but some providers do.

EclipseLink has support for mapping OR data-types including, Structs, Ref, and Arrays. Custom mappings and annotations are used to map these, but the runtime JPA API is the same.

I would not normally recommend usage of OR data-types, as they are less standard than traditional relational tables, and do not give much benefit. Some database defined OR data-types, such as spatial data-types do offer advantages as they have integrated database support.

See,
http://en.wikibooks.org/wiki/Java_Persistence/Advanced_Topics#Structured_Object-Relational_Data_Types