This is the twenty third part of the SQLxD series. For your convenience you can find other parts in the table of contents in Part 1 – XML Transformation

Here go the tests for query parser:

If you followed this series then this whole code should be very easy.

Summary

We now have engine for parsing XML documents, transforming them, and executing queries. We can easily transform rows, perform set operations, implement functions. There are things in SQL-92 which we miss, e.g., nested queries. However, we can easily extend our language and engine to handle them. For now the job is done but if you want you can easily extend the SQLxD database even more.