Understanding EclipseLink, 2.7
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About Data Source Platform Types

EclipseLink abstracts the details of your underlying data source using data source platform classes. A data source platform is owned by your project's Login. Specify your database platform at the project level for all sessions, or override this project-level configuration at the session level.

To configure most platform options, you must use an amendment method, or a preLogin event listener.

EclipseLink interacts with databases using structured query language (SQL). Because each database platform uses its own variation on the basic SQL language, EclipseLink must adjust the SQL it uses to communicate with the database to ensure that the application runs smoothly.

The type of database platform you choose determines the specific means by which the EclipseLink runtime accesses the database, including the type of Java Database Connectivity (JDBC) driver to use. JDBC is an application programming interface (API) that gives Java applications access to a database. EclipseLink relational projects rely on JDBC connections to read objects from, and write objects to, the database. EclipseLink applications use either individual JDBC connections or a JDBC connection pool, depending on the application architecture.

The DatabasePlatform class encapsulates behavior specific to a database platform (such as, Oracle, Sybase, DBase), and provides the protocol for EclipseLink to access this behavior

EclipseLink provides a variety of database-specific platforms that let you customize your project for your target database. For a list of supported database platforms, see org.eclipse.persistence.config.TargetDatabase class and Database Support.

A list of supported application servers can be found in org.eclipse.persistence.config.TargetServer and Application Server Support. The name of the application server you wish to use can be specified with the eclipselink.target-server.persistence unit property.

The datasource-login persistence unit option contains other data source properties you can configure, such as user name, password, connection pooling, and so on. You can implement the Login class, and then set properties specific to database.