[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$f3aB2Q6o0Ck61F6NodIOxbUqsqaaUa8Q1BCmqJB2T2tI":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":16,"related":17,"source":28,"type":29},[],"2024-01-02 12:09:02",125451301,[8,9,10,11],"一个内模式,多个外模式,多个模式","一个内模式,多个外模式,一个模式","多个内模式,多个外模式,一个模式","一个内模式,一个外模式,多个模式",{"courseId":13,"courseImg":14,"courseName":15},"e5f444a87bcff1028cce8aa767cdb688","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F107af2fdf2545b73784977b9cad2041a.png","数据库原理及实用技术（2022-2023-1）","数据库系统的三级模式结构是指数据库系统是由外模式、模式、内模式构成.一个数据库可以有:( )",[18,30,40,49,59,69,79,88,98,108],{"answer":19,"createTime":20,"id":21,"options":22,"question":27,"source":28,"type":29},[],"2024-01-02 12:08:46",125451070,[23,24,25,26],"安全机制","并发控制","认证机制","恢复机制","为了保证多个用户同时对数据库操作而不产生异常情况, 那么数据库系统 必须具有( )","v1",0,{"answer":31,"createTime":32,"id":33,"options":34,"question":39,"source":28,"type":29},[],"2024-01-02 12:08:48",125451082,[35,36,37,38],"'5021',NULL,男,21","'5021','刘祥',NULL,NULL","'5021','刘祥',男,21","NULL,'刘祥',NULL,21","用下面的 SQL 语句建立一个基本表:CREATE TABLE Student(Sno CHAR(4) PRIMARY KEY,Sname CHAR(8) NOT NULL,Sex CHAR(2),Age INT)可以插入到表中的元组是( )",{"answer":41,"createTime":32,"id":42,"options":43,"question":48,"source":28,"type":29},[],125451092,[44,45,46,47],"日志文件、数据库后备副本","数据字典、应用程序、日志文件、审计档案","数据字典、应用程序、审计档案、数据库后备副本","数据字典、应用程序、数据库后备副本","数据库恢复的基础是利用转储的冗余数据.这些转储的冗余数据是 指( )",{"answer":50,"createTime":51,"id":52,"options":53,"question":58,"source":28,"type":29},[],"2024-01-02 12:08:50",125451110,[54,55,56,57],"内模式","外模式","概念模式","存储模式","数据库用户 (程序员或最终用户) 使用的数据视图的描述称为 ( )",{"answer":60,"createTime":61,"id":62,"options":63,"question":68,"source":28,"type":29},[],"2024-01-02 12:08:51",125451117,[64,65,66,67],"都不对","丢失修改(更新)、不可重复读、幻行现象","丢失修改(更新)、不可重复读、读脏数据(污读)","丢失修改(更新)、幻行现象、读脏数据(污读)","并发操作引起的数据不一致性主要包括以下三类: ( )",{"answer":70,"createTime":71,"id":72,"options":73,"question":78,"source":28,"type":29},[],"2024-01-02 12:08:52",125451121,[74,75,76,77],"m:n 联系","1:n 联系","1:1 和 1:n 联系","1:1 联系","层次模型不能直接表示( )",{"answer":80,"createTime":81,"id":82,"options":83,"question":87,"source":28,"type":29},[],"2024-01-02 12:08:53",125451131,[64,84,85,86],"逻辑独立性","物理独立性","物理和逻辑独立性","数据库的每一个外模式,都有一个外模式\u002F模式映象,该映象保证了数据库 数据的:( )",{"answer":89,"createTime":90,"id":91,"options":92,"question":97,"source":28,"type":29},[],"2024-01-02 12:08:54",125451138,[93,94,95,96],"重新选取其他属性","N端实体的关键字","M端实体的关键字","M端实体关键字与N端实体关键字组合","从E-R模型向关系模型转换时,一个m:n联系转换为关系模式时,该关系模式的关键字是( )",{"answer":99,"createTime":100,"id":101,"options":102,"question":107,"source":28,"type":29},[],"2024-01-02 12:08:55",125451154,[103,104,105,106],"数据库完整备份","文件和文件组备份","事务日志备份","数据库差异备份","做文件及文件组备份后,最好做( )备份",{"answer":109,"createTime":100,"id":110,"options":111,"question":116,"source":28,"type":29},[],125451163,[112,113,114,115],"事务一旦提交,对数据库的改变是永久的","一个事务内部的操作及使用的数据对并发的其他事务是隔离的","事务中包括的所有操作要么都做,要么都不做","事务必须是使数据库从一个一致性状态变到另一个一致性状","事务的持久性是指( )"]