The root element of all persistence metadata documents is the
jdo
element. The only legal children
of the jdo
element are package
elements and extension
elements. Each
package
element must specify a
name
attribute giving the full name of the package
it represents. Extensions are used to annotate
metadata with vendor-specific information. The
extension
element may contain arbitrary XML content,
and has three attributes:
Note | |
---|---|
Kodo defines many useful metadata extensions. See Section 6.4, “Metadata Extensions” in the Reference Guide for the complete set. |
Through the course of this chapter, we will build a persistence metadata document for the model above. Our first step is to define the basic metadata structure using the elements we have examined so far: