关键词: 移动数据库, 语义缓存, 一致性维护, 语义裁剪, 属性更新

Abstract:

In order to overcome the disadvantages of the traditional strategy for semantic caching coherency mainte- nance, such as the large data communications flow, the slow update speed and the large occupation of memory space, a new algorithm of semantic caching coherency maintenance based on attribute update is proposed. In this algorithm, the relationship between the semantic caching segment and the conditional predicate as well as the pro- jection attribute of the update operation is analyzed, and a semantic trimming is performed, thus fining the update operation to the exact attribute size. The results of theoretical analyses and simulated experiments show that the new algorithm effectively increases the cache hit ratio, saves the data communication cost and the update time of cache and reduces the data access occupation.

Key words: mobile database, semantic caching, coherency maintenance, semantic trimming, attribute update