The persistence.xml File 
The persistence.xml is a configuration file for setting standard and specific configuration properties of the persistence unit that your entities belong to.
The following table shows the SAP implementation-specific properties of JPA that can be configured in the persistence.xml:
Property |
Description |
com.sap.jpa.sql.mapping |
Setting this property, you can control the JPA calculation of the SQL statements that are sent to the database. The possible values are:
|
com.sap.jpa.versioning.generator.tablename |
When you are working with the system DataSource, which has a default isolation level read_uncommitted, and you are using versioned entities, you can set this property to specify a table name to be used by the version generator. More information: Versioning and Dirty Reads |
com.sap.jpa.execution.foreign-key-handling |
Setting this property, you specify the strategy to be used for handling foreign key constraints on the database. The possible value is:
More information: Native Databases with Foreign Key Constraints |
com.sap.jpa.cache.read-only-classes |
Using this property, you declare read-only entities. More information: Caches in the JPA Implementation The value of this property is a comma-separated list of the fully qualified class names of the entities that are read-only. |
com.sap.jpa.compliance.sap-product-standard |
This property enables/disables the SAP Product Standard Compliance check. The possible values are:
Enabling this property prevents the usage of the Entity cache and the Query Result cache. More information: Caches in the JPA Implementation SAP Note 1169694 |
For information about the standard configurable properties of the persistence.xml, refer to http://java.sun.com.