[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fW91YOKaL4oXsbY2lOr0HtvC4nM_aMHaOQIMlI-oT3-8":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":19,"related":20,"source":24,"type":25},[],"2024-11-28 19:07:04",167930784,[8,9,10,11],"函数","函数依赖","范式","关系",{"count":13,"courseId":14,"courseImg":15,"courseName":16,"workId":17,"workName":18},30,"1197ab5dcae109e97ef84d12a4c314c7","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002Fb7459ab6ad2ca982995f6f9920bada33.jpg","数据库原理及应用","work_39345705","作业4 范式","关系规范化的实质是针对()进行的",[21,26,35,44,49,54,63,72,81,90],{"answer":22,"createTime":5,"id":6,"options":23,"question":19,"source":24,"type":25},[],[8,9,10,11],"v1",0,{"answer":27,"createTime":5,"id":28,"options":29,"question":34,"source":24,"type":25},[],167930785,[30,31,32,33],"插入、删除和数据冗余","提高查询速度","减少数据操作的复杂性","保证数据的安全性和完整性","关系数据库规范化是为解决关系数据库中()问题而引入的",{"answer":36,"createTime":5,"id":37,"options":38,"question":43,"source":24,"type":25},[],167930786,[39,40,41,42],"3NF","BCNF","2NF","1NF","若关系模式R中,消除了非主属性对码的部分依赖,则R至少属于()",{"answer":45,"createTime":5,"id":46,"options":47,"question":48,"source":24,"type":25},[],167930787,[39,40,41,42],"若关系模式R中,每一个函数依赖的决定因素都含码,则R至少属于()",{"answer":50,"createTime":5,"id":51,"options":52,"question":53,"source":24,"type":25},[],167930788,[39,40,41,42],"设R(A,B,C),F={A→B,B→C},则R最高属于()",{"answer":55,"createTime":5,"id":56,"options":57,"question":62,"source":24,"type":25},[],167930789,[58,59,60,61],"可能是1NF","必定是BCNF","必定是3NF","必定是1NF","关系模式中,满足2NF的模式,()",{"answer":64,"createTime":5,"id":65,"options":66,"question":71,"source":24,"type":25},[],167930790,[67,68,69,70],"在R的某一关系中,若两个元组的X值相等,则Y值也相等","在R的每一关系中,若两个元组的X值相等,则Y值也相等","在R的某一关系中,X值应与Y值相等","在R的每一关系中,X值应与Y值相等","在关系模型R中,函数依赖X→Y的语义是()",{"answer":73,"createTime":5,"id":74,"options":75,"question":80,"source":24,"type":25},[],167930791,[76,77,78,79],"性别","学号","学号,姓名","学号,姓名,性别","设学生关系模式为:学生(学号,姓名,年龄,性别,成绩,专业),则该关系模式的主键是()",{"answer":82,"createTime":5,"id":83,"options":84,"question":89,"source":24,"type":25},[],167930792,[85,86,87,88],"自反律","传递律","伪传递律","增广律","如果X→Y(Y不包含于X,且Y不能决定X)和Y→Z成立,那么X→Z成立.这条规则称为()",{"answer":91,"createTime":5,"id":92,"options":93,"question":95,"source":24,"type":25},[],167930793,[42,39,40,94],"4NF","关系模式R\u003Cimg src=\"https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002F5ccf232472dcccb73101580dbd4cbac3.png\">2NF,则R一定是()"]