Designing OQL: Allowing Objects to be Queried

This paper tells the story of OQL the standard query language of the Object Database Management Group ODMG The story starts in at INRIA in the Alta r Groupy The objective of that group was to develop an object oriented database system This objective was reached in September the O database system started its commercial career as the main product of a company called O Technology As opposed to its competitors O featured a full edged query language named O SQL The story goes on with the creation of the ODMG in and the adoption of O SQL as the standard object query language under its new and nal name OQL During the following years OQL went through some modi cations the most important of which resulted in OQL that o ers some level of compliance with SQL On top of providing the expressive power of the SQL query language OQL allows objects to be queried This is a claim also supported by the upcoming SQL However due to its adequacy to the object oriented type system and its functional nature OQL is much simpler to learn use and implement A goal of this paper is to demonstrate this This paper tells about the mistakes and pertinent choices we made while designing and implementing OQL I hope it also conveys the great pleasure I had to be part of this adventure