Because performance is a crucial issue in database systems, data caching techniques have been studied in database research field, especially in client-server databases and distributed databases. Recently, the idea of semantic caching has been proposed. The approach uses semantic information to describe cached data items so that it tries to exploit not only temporal locality but also semantic locality to improve query response time. In this paper, we propose linear constraint-based semantic caching as a new approach, we describe the semantic information about the cached relational tuples as compact constraint tuples. The focus in this paper is the representation method of cache information and the cache examination algorithm.