Chain-based evaluation - a bridge linking recursive and nonrecursive query evaluation

Many recursive query analysis techniques are qualitative in nature. This contrasts sharply with relational query optimization which relies heavily on quantitative analysis. In this paper, we show that chain-based evaluation facilitates quantitative analysis of recursive queries based on the available chain information, database statistics and other quantitative measurements. Chain-based evaluation not only facilitates binding propagation, constraint pushing and the selection of recursive query evaluation algorithms but also provides precise compile chain forms in relational expressions. Since most recursions in database applications can be compiled into highly regular chain forms, chain-based evaluation is promising at bridging recursive and nonrecursive database query evaluation.