Abstract: This invention relates generally to a system for processing database queries, and more particularly to a method for generating high level language or machine code to implement query execution plans. The present invention provides a method for generating executable machine code for query execution plans, that is adaptive to dynamic runtime conditions, that is compiled just in time for execution and most importantly, that avoids the bounds checking, pointer indirection, materialization and other similar kinds of overhead that are typical in interpretive runtime execution engines.