基于减少检索的负表约束优化算法

摘要

通过放弃不相关元组从而减少检索的方式,提出一种优化算法STRN3,解决了在相容性算法中重复遍历负表约束的全部元组,导致冗余检索、效率较低的问题.实验结果表明,在检索过程中,当负表中有效元组的平均个数未呈现大幅度下降时,STRN3算法较STR-N算法性能更优;在约束网络中,支持元组更多的情况下,STRN3算法较 STR3算法性能更优,从而实现了对负表约束算法的改进.%By abandoning irrelevant tuples and reducing the way of retrieval,we presented an optimization algorithm STRN3,which solved the problem that all the tuples of negative table constraint were traversed in the compatibility algorithm,resulting in redundant retrieval and low efficiency.The experimental results show that the performance of the algorithm STRN3 is better than that of the algorithm STR-N when the average number of the valid tuples in the negative table does not decrease substantially in the retrieval process.In the constraint networks,when the number of supported tuples is more than conflict tuples,the performance of the algorithm STRN3 is better than that of the algorithm STR3,thus the improvement of the negative table constraint algorithm is realized.