TBAR: An efficient method for association rule mining in relational databases. In this paper, we propose a new algorithm for efficient association rule mining, which we apply in order to discover interesting patterns in relational databases. Our algorithm, which is called Tree-Based Association Rule mining (TBAR), redefines the notion of item and employs an effective tree data structure. It can also use techniques such as direct hashing and pruning. Experiments with real-life datasets show that TBAR outperforms Apriori, a well-known and widely used algorithm.