OCLS hosts and maintains the Colleges Union Catalogue. This catalogue is comprised primarily of bibliographic and corresponding authority records. The Union Catalogue is provided for the benefit of the students, faculty, and staff of the Colleges. OCLS hosts and operates the catalogue for all of the publicly-funded community colleges in Ontario.
A union catalogue traditionally represents a static, non-circulating collection, with limited live circulation data available. In this typical scenario, each participating Library or location would maintain and operate their own integrated library system and periodically update the union catalogue by forwarding their catalogue records to be uploaded.
The Ontario Colleges' current catalogue is a combination of this model and a virtual model where some College Libraries send their records electronically via protocols such as Z39.50 allowing for seamless integration into the union catalogue.