Oracle XML DB

I know XML. But I don't know XDB, which is Oracle's XML DB. It is actually a set of technologies paired with an Oracle database. The two main pieces are (1) XMLType tables/views, and (2) the XML DB Repository. The repository holds resources such as folders and files.

XML DB is a native XML storage technology. The tech supports XML standards such as XML schemas. You register the schemas, and it creates some tables to hold the info. You can access the XML data through HTTP, SQL, JDBC, WebDAV, or FTP.

Messaging is done with the Oracle Streams AQ. XMLType can be used as the payload type. You can queue up XMLType messages. There are a number of APIs to use XML DB. These include XMLType (surprise), DBMS_XDB, and a number of other PL/SQL packages that start with DBMS_XDB*.

There are a bunch of new views to check on XML DB info. Here are the DBA views:

• DBA_XML_SCHEMAS
• DBA_XML_TABLES
• DBA_XML_TAB_COLS
• DBA_XML_VIEWS
• DBA_XML_VIEW_COLS

You get the USER_* and ALL_* corresponding views as well. XML text is stored in CLOBs. There are two ways to handle storage: (1) unstructured storage, and (2) structured storage. Unstructured is fast. Structured uses up less space but increases overhead during processing.

XML DB supports the SQL/XML standard. It requires at least Oracle 9R2. Altova, the people who make XMLSpy, have an editor for XML DB. There is a lot of info out there on how to install XML DB. If you are upgrading an existing DB, you should install XML DB manually. Otherwise you can use the Database Configuration Assistant (DBCA).

XML DB can be managed with Oracle Enterprise Manager. The internal configuration is done via the "xdbconfig.xml" file.