Working with XML and Databases

Many relational databases now support XML so that you can store or retrieve data through XML files. You can use an XML model to generate an annotated schema that will allow you to store or retrieve data in such a database.

The following databases are available :

Database	Mapped XML model	Targeted XML language	Required XEM file
Microsoft SQL Server 2000	Yes	XSD or XDR	Microsoft SQL Server
Oracle 9i2	No	XSD	Oracle 9i2
IBM DB2 v8.1	Yes	DTD	IBM DB2 DAD

By attaching the SQL/XML extended model definition to an XML model mapped to a PDM, you can also generate SQL/XML queries to retrieve data in an XML format, from relational databases supporting SQL/XML.

The best way to generate SQL/XML queries is to use the XML Builder Wizard which helps you build an XML model from a PDM. The generated XML model is mapped to the PDM and automatically linked to the SQL/XML extended model definition. (See Generating SQL/XML queries)

Note: You can also generate PDM tables from an XML schema. For more information, see Generating Other Models from an XSM.

Mapping Database Objects to an XML Schema Via the XML Builder Wizard
You can create an XSM to generate an annotated schema from a PDM via the XML Builder.
Generating SQL/XML Queries
SQL/XML is an XML extension of the Structured Query Language, which allows you to retrieve relational data using extended SQL syntax, and produce an XML result. SQL/XML has five main elements:
Generating an Annotated Schema for Microsoft SQL Server 2000
Microsoft SQL Server 2000 is an XML-enabled database server, which supports annotations that can be used on XSD or XDR files, to map XML data to relational data.
Generating an Annotated Schema for Oracle 9i2
Oracle 9i2 is a database server with a native XML storage and retrieval technology called Oracle XML DB. There is no mapping between XML data and relational data. Tables, columns and abstract data types (ADT) are created from annotated schemas (XSDs). Annotated schemas are XML-coded files, targeted with an XML language and tagged with specific DBMS annotations, that allow you to store or retrieve data in an XML format, from relational databases supporting XML.
Generating a DAD File for IBM DB2
IBM DB2 v8.1 (or higher) is a database server with an add-in for XML storage and retrieval called IBM DB2 Extender. XML data (elements, attributes) are mapped to relational data (tables, columns) through Document Access Definition files (.DAD).