When to use annotated XML schema decomposition

In certain cases you may want to store the contents of XML documents within a collection of relational database tables, but the schema to which those XML documents conform does not readily match the column definitions of the target tables. XML schema decomposition is designed to solve this problem.

When an XML schema does not clearly match the database table structure, you might need to adjust either the XML schema or the relational table schema, or both, in order for the documents to fit the table structure. However, changes to either of these might not always be possible or could be prohibitively expensive, especially if existing applications depend on the relational schema having a particular structure.

Annotated XML schema decomposition addresses this problem by enabling you to decompose documents that are based on new or existing XML schemas, into new or existing tables. This is possible because of the various features available in annotated XML schema decomposition. These features, which are expressed as annotations added to the XML schema documents, offer flexibility in mapping an XML schema structure to a relational table structure.