通过引入汇总表来提高一些经常执行的聚集查询的性能，这属于下列数据库应用系统开发过 程中哪个阶段的任务
A、需求分析D
暂无解析
Manypatientsinsistonhavingwatcheswiththeminhospital,______theyhavenoschedulestokeep.
Whatarethecharacteristicsofgoodwritings?
2岁内小儿心尖搏动的位置是（）
Veryfewpeopleunderstoodthiscontract,______wasveryobscure.
Ifyou_______inbehavinginthiswayyouwillbringyourselfnothingbuttrouble.
