The Object Constraint Language (OCL) is a textual sublanguage of the Unified Modelling Language (UML). It can be used to express additional constraints on UML models that cannot be expressed, or are very difficult to express, with the graphical means provided by UML. OCL is based on first-order predicate logic but it uses a syntax similar to programming languages and closely related to the syntax of UML. It is, thus, more adequate for every-day modelling than pure first-order predicate logic.

Although OCL is thus an important tool, it can be hard to find information about it.
For example, there is still a lack of good teaching modules for OCL. Furthermore, case studies on projects could help potential users to find out whether or not OCL is the proper formalism for their problems. 

The worldwide OCL community has developed various (open-source) OCL tools. These can and should be integrated into UML CASE tools to support precise specification of UML models beyond the pure specification of OCL expressions as strings.

For this reason, the OCL community decided at the 2005 Workshop on OCL at the MoDELS conference to set up an OCL portal website collecting all information about OCL. This is it!

This page relies on your collaboration. Therefore you are invited to put your OCL activities/knowledge at the portal! The OCL Portal provides editing capabilities both to members of the academic/research OCL community and OCL users/developers of CASE tools in industrial environments. Please register and then you will (after the confirmation procedure) be able to add your own teaching material, projects, toolkits, case studies etc. Furthermore, we are always happy on feedback about this site and will make every effort to improve the site in accordance with your needs and suggestions.