B Oracle XML DB Restrictions

This appendix describes the restrictions associated with Oracle XML DB.

• Extending Resource Metadata Properties – You cannot extend the resource schema. However, you can set and access custom properties belonging to other namespaces, other than XDBResource.xsd, using DOM operations on the <Resource> document.

• References Within Scalars – Oracle does not support references within a scalar, XMLType, or LOB data column.

• Thin JDBC Driver Not Supported by Some XMLType Functions – Methods extract(), transform(), and existsNode() work with the thick JDBC driver only. Not all oracle.xdb.XMLType functions are supported by the thin JDBC driver. If you do not use oracle.xdb.XMLType classes and the OCI driver, you could lose performance benefits.

• NCHAR, NVARCHAR and NCLOB Not Supported for SQLType – Oracle XML DB does not support NCHAR, NVARCHAR, and NCLOB as SQLType. You cannot specify that an element is to be of type NCHAR, NVARCHAR, or NCLOB. Also, if you provide your own type, do not use any of these data types.

• Identifier Length Limited to 4000 Characters – Oracle XML DB supports only XML identifiers that are 4000 characters long, or shorter.