You can combine the features of Oracle Text and Oracle XML DB to create an XML Search Index for applications where you want to do a full-text retrieval, leveraging the XML structure by entering queries such as "find all nodes that contain the word Pentium." Oracle Database 12c extends Oracle's support for the W3C XQuery specification by adding support for the XQuery full-text extension, which enables you to perform XML-aware full-text searches on XML content stored in the database.
The following topics explain how to use Oracle XML DB with Oracle Text applications:
Oracle Text Reference for information about the xml_enable variable of SET_SEC_GRP_ATTR to enable XML awareness
Oracle XML DB Developer's Guide for more information about XML full-text indexing and XML Search Index