数据库系统概念（杨冬青）习题答案Chapter1providesageneraloverviewofthenatureandpurposeofdatabasesystems.Themostimportantconceptinthischapteristhatdatabasesystemsallowdatatobetreatedatahighlevelofabstraction.Thus,databasesystemsdiffersignificantlyfromthefilesystemsandgeneralpurposeprogrammingenvironmentsw