50 Introduction to XML Descriptors

This chapter introduces options specific to an XML descriptor.

This chapter includes the following section:

For information on descriptor concepts and features common to more than one type of TopLink descriptors, see Chapter 16, "Introduction to Descriptors".

50.1 XML Descriptor Concepts

XML descriptors describe Java objects that you map to simple and complex types defined by an XML schema document (XSD).

Using XML descriptors in an XML project, you can configure XML mappings (see Section 53.1, "XML Mapping Types"), in memory, to XML elements defined by an XSD.

For more information, see the following:

50.1.1 XML Descriptors and Aggregation

When working with descriptors for a parent (source) and a child (target) objects, you have to accomplish the following:

  • if the source object exists, then you must ensure that the target object also exists;

  • if the source object is destroyed, then you must ensure that the target object is also destroyed.

For more information, seeSection 16.2.5, "Descriptors and Aggregation".

In your XML project, designate the descriptors for the source and target objects to reflect this relationship as Composite Descriptors in XML Projects. Composite Descriptors in XML Projects

In an XML project, descriptors are always composites.

Because XML descriptors are always composites, you can configure inheritance for an XML descriptor without considering its type (see Section 16.3, "Descriptors and Inheritance").