4. The method as claimed in claim 2, further comprising the step of parsing said inner and outer query to form a linked data structure including a first node representing said inner query and a second node representing said outer query.
2. The method as claimed in claim 1, wherein said inner query and said outer query are expressed in a query language including alphanumeric names for said first and second relations and alphanumeric symbols for operators in said first and second predicates.