Useful links regarding query processing, optimization, etc.:

• Conceptual Queries

• ORM Conceptual Queries and the ConQuer query language

• A Query Algebra for Object-Oriented Databases

• Optimizing Object Queries Using an Effective Calculus

• Generic Functions/CLOS DB stuff

• Gestalt-class: A Persistent, Multi-user CLOS Application Environment

• Open Source Implementations

• XXL - a Java query processing library

• Lambda-DB (Monoid Comprehension Calculus -> Relational Algebra)

Lambda-DB includes a C++ implementation of the algorithms described in "Optimizing Object Queries Using an Effective Calculus", above.

• Outer Join Processing

• Outerjoin Simplication and Reordering for Query Optimization

• Outerjoins as Disjunctions

• Misc. Optimization Techniques

• Performing Group-By before Join

• Guy with a 300 page draft on query compilation

• Optimizing Queries across Diverse Data Sources

• Python Stuff:

• Integrating Diverse Data Sources with Gadfly 2

• SQLObject library for Python (Performs SQL operations using Pythonic syntax)

• Other

• Database System Concepts, 4th Edition

• Proceedings of the 27th International Conference on Very Large Databases

• Foundations of Object-Relational Mapping

• Visual XXL - "Runtime 3D-Visualization of Relational Database-Queries"

• Good info on ANSI SQL-92 syntax/semantics