Abstract: In an EclipseLink environment, persistence units are associated with a single data source. However, in accordance with an embodiment, a user can define multiple persistence units, each with a different set of entity types (i.e., classes) stored in multiple data sources, and expose them through a single composite persistence unit which combines the entities from across the multiple data sources through a single persistence context. A plurality of different types of data sources can be used, including Java Transaction API (JTA) and non-JTA data sources as well as EclipseLink's native JDBC connection pools. Each member persistence unit continues mapping its classes to its own data source. Therefore, a composite persistence unit allows one to map different entities to different data sources. Composite persistence units can be created at runtime.

Abstract: In an EclipseLink environment, persistence units are associated with a single data source. However, in accordance with an embodiment, a user can define multiple persistence units, each with a different set of entity types (i.e., classes) stored in multiple data sources, and expose them through a single composite persistence unit which combines the entities from across the multiple data sources through a single persistence context. A plurality of different types of data sources can be used, including Java Transaction API (JTA) and non-JTA data sources as well as EclipseLink's native JDBC connection pools. Each member persistence unit continues mapping its classes to its own data source. Therefore, a composite persistence unit allows one to map different entities to different data sources. Composite persistence units can be created at runtime.