XML Datatypes in Oracle 9i

Question

My database architect would like to leverage the XML datatype support that is new in Oracle 9i. How can I configure TopLink to directly map object attributes to elements in an XML structure that is stored in an XML-type column?

Answer 1

Marc,
Yes. It is possible to map XMLType columns into your object model. It is accomplished using a direct-to-field mapping where the database column is an XMLType and the object model's attribute is a Document or String. In 9.0.3 of Oracle9iAS TopLink you must include the xdb.jar on your classpath, customize your configuration with an extended ConversionManager, and use a DescriptorEventListener.
ConversionManager: Subclass the provided one and provide a conversion from XMLType to either the underlying DOM Document or XML representation of the string.
DescriptorEventListener: Implement and register an event listener that will provide aboutToInsert and aboutToUpdate events for the class you are mapping the XML into. In these events you'll need to make use of the provided JDBC connection to convert the Document or String back into an XMLType object. (NOTE: If using Strings I believe you must use Oracle's XML parser to re-build the Document)
A more detail technical tip will be availble soon and will be available through TopLink's OTN page (http://otn.oracle.com/products/ias/toplink/).
Doug Clarke
Product Manager
Oracle9iAS TopLink