Oracle: Relational DB to XML

Ken Sall

December 20, 1999

Steve Muench, Oracle's Lead XML Evangelist, gave an excellent presentation and demo of the use of XML, XSLT and XPath, and XSQL servlet technology supported by (various versions of) Oracle 8i.

Muench explained that relational databases are used by most of the top Web sites because they sport data warehousing, content management, back office integration, and self-service b2b eCommerce. XML is useful in creating a logical common format on top of the database tables; relational databases excel at quickly extracting layered, logical views. However, there is a trend toward object relational databases (such as with products from Oracle and IBM) in which structure is important and a whole data model is needed, not just a collection of flat tables (as in RDBMS). Object Views deliver rich structured data from the flat tables. In the Oracle object-relational database, object views allow you to retrieve, update, insert, and delete relational data as if they were stored as object types. Views that have columns which are object datatypes can also be defined. Muench said that object relational databases like Oracle8i:

easily mix structured and unstructured data
process XML with "Amazon"-like reliability and scalability
handle XML without changing existing tools and apps
form the hub, with Oracle Integration Server, of loosely-coupled, reliable, XML-based messaging

See also Benefits that the Oracle 8i Object-Relational Database Provides (requires free login). A related Muench's article, "Using XML and Relational Databases for Internet Applications", states:

Oracle8i and XML help companies create strategic advantage by dramatically simplifying the acquisition, integration, repurposing, and exchange of information over the Internet. Once that XML-based information is safely stored in an Oracle database, it can be searched and mined and processed and presented in familiar, powerful ways.... [The Oracle8i/XML combination] provides a compelling technology platform to further profit from opportunities where Electronic Commerce, Data Warehousing, Content Management, and Back Office Integration flow together.

Serving XML data over the Web is easy with XSQL Servlet, according to Muench. There are four approaches:

Dynamic XML Documents Made Easy - given a "Page Full 'o Queries", make XML
Declarative, Template-Based Approach - just add <xsql:query> tags to your XML template
Transform Resulting XML Document - using XSLT in the server or in the client
Post XML for Insertion into the Database - automates use of transformation and XML SQL utility

He also discussed Oracle XDK - XML Developer's Kit, which consists of these components: