We first provide an example to show that two previously published results in 2 and 4 on tree pattern containment under schema graphs are incorrect. We then show that the original result in 2 holds under some special conditions on the schema graph. We show some published results on chasing tree pattern queries using schema constraints for tree pattern containment test are incorrect.We present a revised result which requires some special conditions on the schema graph.We point out some extensions to the revised result.
['Junhu Wang', 'Jeffrey Xu Yu', 'Jixue Liu', 'Chaoyi Pang']
A revised result on chasing tree patterns under schema graphs