[{"data":1,"prerenderedAt":884},["ShallowReactive",2],{"note:cs\u002Fdb\u002F100+70\u002FDay11-数据库70题-综合48-61":3},{"id":4,"title":5,"body":6,"description":16,"extension":878,"meta":879,"navigation":361,"path":880,"seo":881,"stem":882,"__hash__":883},"notes\u002Fsource\u002Fcs\u002Fdb\u002F100+70\u002FDay11-数据库70题-综合48-61.md","Day 11 - 数据库70题：综合题 48-61",{"type":7,"value":8,"toc":859},"minimark",[9,13,17,22,25,41,44,58,94,109,113,120,122,125,152,166,173,176,180,182,185,256,259,294,297,301,304,318,321,326,328,472,476,478,520,524,526,567,570,574,576,579,607,610,652,655,659,661,677,680,684,686,689,692,696,698,701,715,718,739,742,746,748,751,762,765,769,771,774,777,781,783,786,789,803,806,810,812,815,823,826,830,832,835,838,852,855],[10,11,5],"h1",{"id":12},"day-11-数据库70题综合题-48-61",[14,15,16],"p",{},"参考重点：教材第 7 章数据库设计，第 5 章完整性，第 11-12 章事务、恢复、并发控制。原文件缺综合题 53。",[18,19,21],"h2",{"id":20},"_48-某大学实行学分制学生可根据自己情况选修课程每名学生可同时选修多门课程每门课程可由多位教师讲授每位教师可讲授多门课程不完整-e-r-图含学生课程教师三个实体","48. 某大学实行学分制，学生可根据自己情况选修课程。每名学生可同时选修多门课程，每门课程可由多位教师讲授；每位教师可讲授多门课程。不完整 E-R 图含学生、课程、教师三个实体。",[14,23,24],{},"要求：",[26,27,28,32,35,38],"ol",{},[29,30,31],"li",{},"指出学生与课程的联系类型，完善 E-R 图。",[29,33,34],{},"指出课程与教师的联系类型，完善 E-R 图。",[29,36,37],{},"若每名学生有一位教师指导，每一位教师指导多名学生，则学生与教师是何联系？",[29,39,40],{},"在原 E-R 图上补画教师与学生的联系。",[14,42,43],{},"答案：",[26,45,46,49,52,55],{},[29,47,48],{},"学生与课程是多对多联系。一个学生可选多门课，一门课可被多名学生选。",[29,50,51],{},"课程与教师是多对多联系。一门课可由多位教师讲授，一位教师可讲多门课。",[29,53,54],{},"学生与教师是多对一联系，从教师到学生看是一对多：一名学生只有一位指导教师，一位教师可指导多名学生。",[29,56,57],{},"完整 E-R 可表示为：",[59,60,65],"pre",{"className":61,"code":62,"language":63,"meta":64,"style":64},"language-mermaid shiki shiki-themes github-light github-dark","erDiagram\n    学生 }o--o{ 课程 : 选修\n    教师 }o--o{ 课程 : 讲授\n    教师 ||--o{ 学生 : 指导\n","mermaid","",[66,67,68,76,82,88],"code",{"__ignoreMap":64},[69,70,73],"span",{"class":71,"line":72},"line",1,[69,74,75],{},"erDiagram\n",[69,77,79],{"class":71,"line":78},2,[69,80,81],{},"    学生 }o--o{ 课程 : 选修\n",[69,83,85],{"class":71,"line":84},3,[69,86,87],{},"    教师 }o--o{ 课程 : 讲授\n",[69,89,91],{"class":71,"line":90},4,[69,92,93],{},"    教师 ||--o{ 学生 : 指导\n",[14,95,96,97,100,101,104,105,108],{},"讲解：E-R 联系类型判断只看业务约束。",[66,98,99],{},"选修"," 和 ",[66,102,103],{},"讲授"," 都是 M:N，转换为关系模式时一般需要单独的联系表；",[66,106,107],{},"指导"," 是 1:N，可在学生表中加入指导教师外键。",[18,110,112],{"id":111},"_49-将图-56-的-e-r-图转换为关系模式菱形框中的属性自己确定","49. 将图 5.6 的 E-R 图转换为关系模式，菱形框中的属性自己确定。",[14,114,115,116,119],{},"题面图示：实体“单位”含属性单位号、地址、电话；实体“职工”含属性职工号、姓名、性别、年龄、单位号；单位与职工之间有联系 ",[66,117,118],{},"D-3","。",[14,121,43],{},[14,123,124],{},"按常见语义，一个单位有多个职工，一个职工属于一个单位，是 1:N 联系。可转换为：",[126,127,128,137],"ul",{},[29,129,130,133,134],{},[66,131,132],{},"单位(单位号, 地址, 电话)","，主键：",[66,135,136],{},"单位号",[29,138,139,133,142,145,146,148,149],{},[66,140,141],{},"职工(职工号, 姓名, 性别, 年龄, 单位号)",[66,143,144],{},"职工号","，外键：",[66,147,136],{}," 引用 ",[66,150,151],{},"单位(单位号)",[14,153,154,155,157,158,161,162,165],{},"如果菱形联系 ",[66,156,118],{}," 有自定属性，例如 ",[66,159,160],{},"入职日期","，则该属性可并入 N 端的 ",[66,163,164],{},"职工"," 关系：",[126,167,168],{},[29,169,170],{},[66,171,172],{},"职工(职工号, 姓名, 性别, 年龄, 单位号, 入职日期)",[14,174,175],{},"讲解：1:N 联系转换为关系模式时，一般把 1 端主键加入 N 端作为外键；只有 M:N 联系才必须单独生成联系表。",[18,177,179],{"id":178},"_50-设有商业销售记账数据库一个顾客顾客姓名单位电话号码可以买多种商品一种商品商品名称型号单价供应多个顾客试画出对应的-e-r-图","50. 设有商业销售记账数据库。一个顾客（顾客姓名，单位，电话号码）可以买多种商品，一种商品（商品名称，型号，单价）供应多个顾客。试画出对应的 E-R 图。",[14,181,43],{},[14,183,184],{},"顾客和商品是多对多联系，联系可命名为“购买”或“销售”，联系属性可按记账需要加入数量、日期、金额等。",[59,186,188],{"className":61,"code":187,"language":63,"meta":64,"style":64},"erDiagram\n    顾客 }o--o{ 商品 : 购买\n    顾客 {\n        string 顾客姓名\n        string 单位\n        string 电话号码\n    }\n    商品 {\n        string 商品名称\n        string 型号\n        decimal 单价\n    }\n",[66,189,190,194,199,204,209,215,221,227,233,239,245,251],{"__ignoreMap":64},[69,191,192],{"class":71,"line":72},[69,193,75],{},[69,195,196],{"class":71,"line":78},[69,197,198],{},"    顾客 }o--o{ 商品 : 购买\n",[69,200,201],{"class":71,"line":84},[69,202,203],{},"    顾客 {\n",[69,205,206],{"class":71,"line":90},[69,207,208],{},"        string 顾客姓名\n",[69,210,212],{"class":71,"line":211},5,[69,213,214],{},"        string 单位\n",[69,216,218],{"class":71,"line":217},6,[69,219,220],{},"        string 电话号码\n",[69,222,224],{"class":71,"line":223},7,[69,225,226],{},"    }\n",[69,228,230],{"class":71,"line":229},8,[69,231,232],{},"    商品 {\n",[69,234,236],{"class":71,"line":235},9,[69,237,238],{},"        string 商品名称\n",[69,240,242],{"class":71,"line":241},10,[69,243,244],{},"        string 型号\n",[69,246,248],{"class":71,"line":247},11,[69,249,250],{},"        decimal 单价\n",[69,252,254],{"class":71,"line":253},12,[69,255,226],{},[14,257,258],{},"可转换为关系模式：",[126,260,261,274,286],{},[29,262,263,266,267,270,271],{},[66,264,265],{},"顾客(顾客姓名, 单位, 电话号码)","，主键可暂取 ",[66,268,269],{},"顾客姓名","，实际系统建议增加 ",[66,272,273],{},"顾客编号",[29,275,276,279,280,270,283],{},[66,277,278],{},"商品(商品名称, 型号, 单价)","，主键可取 ",[66,281,282],{},"(商品名称, 型号)",[66,284,285],{},"商品编号",[29,287,288,279,291],{},[66,289,290],{},"购买(顾客姓名, 商品名称, 型号, 数量, 购买日期)",[66,292,293],{},"(顾客姓名, 商品名称, 型号, 购买日期)",[14,295,296],{},"讲解：题面没有给出顾客编号和商品编号，考试可直接用自然属性作码；真实数据库设计中更建议使用稳定的代理键。",[18,298,300],{"id":299},"_51-某医院病房计算机管理中需要如下信息并完成-e-r-图关系模型和候选码","51. 某医院病房计算机管理中需要如下信息，并完成 E-R 图、关系模型和候选码。",[14,302,303],{},"题面信息：",[126,305,306,309,312,315],{},[29,307,308],{},"科室：科名，科地址，科电话，医生姓名",[29,310,311],{},"病房：病房号，床位号，所属科室名",[29,313,314],{},"医生：姓名，职称，所属科室名，年龄，工作证号",[29,316,317],{},"病人：病历号，姓名，诊断，主管医生，病房号",[14,319,320],{},"约束：一个科室有多个病房、多个医生；一个病房只能属于一个科室；一个医生只属于一个科室，但可负责多个病人的诊治；一个病人的主管医生只有一个。",[322,323,325],"h3",{"id":324},"_511-e-r-图","51.1 E-R 图",[14,327,43],{},[59,329,331],{"className":61,"code":330,"language":63,"meta":64,"style":64},"erDiagram\n    科室 ||--o{ 病房 : 拥有\n    科室 ||--o{ 医生 : 隶属\n    医生 ||--o{ 病人 : 主管\n    病房 ||--o{ 病人 : 收治\n\n    科室 {\n        string 科名\n        string 科地址\n        string 科电话\n    }\n    病房 {\n        string 病房号\n        string 床位号\n    }\n    医生 {\n        string 工作证号\n        string 姓名\n        string 职称\n        int 年龄\n    }\n    病人 {\n        string 病历号\n        string 姓名\n        string 诊断\n    }\n",[66,332,333,337,342,347,352,357,363,368,373,378,383,387,392,398,404,409,415,421,427,433,439,444,450,456,461,467],{"__ignoreMap":64},[69,334,335],{"class":71,"line":72},[69,336,75],{},[69,338,339],{"class":71,"line":78},[69,340,341],{},"    科室 ||--o{ 病房 : 拥有\n",[69,343,344],{"class":71,"line":84},[69,345,346],{},"    科室 ||--o{ 医生 : 隶属\n",[69,348,349],{"class":71,"line":90},[69,350,351],{},"    医生 ||--o{ 病人 : 主管\n",[69,353,354],{"class":71,"line":211},[69,355,356],{},"    病房 ||--o{ 病人 : 收治\n",[69,358,359],{"class":71,"line":217},[69,360,362],{"emptyLinePlaceholder":361},true,"\n",[69,364,365],{"class":71,"line":223},[69,366,367],{},"    科室 {\n",[69,369,370],{"class":71,"line":229},[69,371,372],{},"        string 科名\n",[69,374,375],{"class":71,"line":235},[69,376,377],{},"        string 科地址\n",[69,379,380],{"class":71,"line":241},[69,381,382],{},"        string 科电话\n",[69,384,385],{"class":71,"line":247},[69,386,226],{},[69,388,389],{"class":71,"line":253},[69,390,391],{},"    病房 {\n",[69,393,395],{"class":71,"line":394},13,[69,396,397],{},"        string 病房号\n",[69,399,401],{"class":71,"line":400},14,[69,402,403],{},"        string 床位号\n",[69,405,407],{"class":71,"line":406},15,[69,408,226],{},[69,410,412],{"class":71,"line":411},16,[69,413,414],{},"    医生 {\n",[69,416,418],{"class":71,"line":417},17,[69,419,420],{},"        string 工作证号\n",[69,422,424],{"class":71,"line":423},18,[69,425,426],{},"        string 姓名\n",[69,428,430],{"class":71,"line":429},19,[69,431,432],{},"        string 职称\n",[69,434,436],{"class":71,"line":435},20,[69,437,438],{},"        int 年龄\n",[69,440,442],{"class":71,"line":441},21,[69,443,226],{},[69,445,447],{"class":71,"line":446},22,[69,448,449],{},"    病人 {\n",[69,451,453],{"class":71,"line":452},23,[69,454,455],{},"        string 病历号\n",[69,457,459],{"class":71,"line":458},24,[69,460,426],{},[69,462,464],{"class":71,"line":463},25,[69,465,466],{},"        string 诊断\n",[69,468,470],{"class":71,"line":469},26,[69,471,226],{},[322,473,475],{"id":474},"_512-转换为关系模型结构","51.2 转换为关系模型结构",[14,477,43],{},[126,479,480,485,495,502,514],{},[29,481,482,119],{},[66,483,484],{},"科室(科名, 科地址, 科电话)",[29,486,487,490,491,494],{},[66,488,489],{},"医生(工作证号, 姓名, 职称, 年龄, 科名)","，",[66,492,493],{},"科名"," 为外键。",[29,496,497,490,500,494],{},[66,498,499],{},"病房(病房号, 科名)",[66,501,493],{},[29,503,504,490,507,510,511,119],{},[66,505,506],{},"床位(病房号, 床位号)",[66,508,509],{},"病房号"," 为外键。若题目把“病房号+床位号”整体看作病房实体，也可写成 ",[66,512,513],{},"病房床位(病房号, 床位号, 科名)",[29,515,516,519],{},[66,517,518],{},"病人(病历号, 姓名, 诊断, 主管医生工作证号, 病房号)","，主管医生和病房号为外键。",[322,521,523],{"id":522},"_513-每个关系模式的候选码","51.3 每个关系模式的候选码",[14,525,43],{},[126,527,528,536,544,551,559],{},[29,529,530,533,534],{},[66,531,532],{},"科室","：",[66,535,493],{},[29,537,538,533,541],{},[66,539,540],{},"医生",[66,542,543],{},"工作证号",[29,545,546,533,549],{},[66,547,548],{},"病房",[66,550,509],{},[29,552,553,533,556],{},[66,554,555],{},"床位",[66,557,558],{},"(病房号, 床位号)",[29,560,561,533,564],{},[66,562,563],{},"病人",[66,565,566],{},"病历号",[14,568,569],{},"讲解：原题“科室”属性中列了“医生姓名”，但因为一个科室有多个医生，医生不应作为科室表中的多值属性，应拆成医生实体并用外键表示所属科室。",[18,571,573],{"id":572},"_52-叙述数据库实现完整性检查的方法","52. 叙述数据库实现完整性检查的方法。",[14,575,43],{},[14,577,578],{},"DBMS 实现完整性检查一般包括：",[26,580,581,601,604],{},[29,582,583,584,587,588,587,591,587,594,587,597,600],{},"提供完整性约束定义机制，如 ",[66,585,586],{},"PRIMARY KEY","、",[66,589,590],{},"FOREIGN KEY",[66,592,593],{},"UNIQUE",[66,595,596],{},"CHECK",[66,598,599],{},"NOT NULL","、触发器。",[29,602,603],{},"在执行插入、删除、修改时自动检查约束。",[29,605,606],{},"发现违约时执行违约处理，如拒绝操作、级联更新、级联删除、置空、置默认值。",[14,608,609],{},"SQL Server 示例：",[59,611,615],{"className":612,"code":613,"language":614,"meta":64,"style":64},"language-sql shiki shiki-themes github-light github-dark","CREATE TABLE dbo.Enrollment (\n    Sno varchar(20) NOT NULL,\n    Cno varchar(20) NOT NULL,\n    Grade decimal(5, 2) NULL,\n    CONSTRAINT PK_Enrollment PRIMARY KEY (Sno, Cno),\n    CONSTRAINT CK_Enrollment_Grade CHECK (Grade BETWEEN 0 AND 100)\n);\n","sql",[66,616,617,622,627,632,637,642,647],{"__ignoreMap":64},[69,618,619],{"class":71,"line":72},[69,620,621],{},"CREATE TABLE dbo.Enrollment (\n",[69,623,624],{"class":71,"line":78},[69,625,626],{},"    Sno varchar(20) NOT NULL,\n",[69,628,629],{"class":71,"line":84},[69,630,631],{},"    Cno varchar(20) NOT NULL,\n",[69,633,634],{"class":71,"line":90},[69,635,636],{},"    Grade decimal(5, 2) NULL,\n",[69,638,639],{"class":71,"line":211},[69,640,641],{},"    CONSTRAINT PK_Enrollment PRIMARY KEY (Sno, Cno),\n",[69,643,644],{"class":71,"line":217},[69,645,646],{},"    CONSTRAINT CK_Enrollment_Grade CHECK (Grade BETWEEN 0 AND 100)\n",[69,648,649],{"class":71,"line":223},[69,650,651],{},");\n",[14,653,654],{},"讲解：完整性检查应尽量靠 DBMS 统一执行，而不是分散在多个应用程序中。",[18,656,658],{"id":657},"_54-事务中的提交和回滚是什么意思","54. 事务中的提交和回滚是什么意思？",[14,660,43],{},[126,662,663,670],{},[29,664,665,666,669],{},"提交：事务成功结束，使用 ",[66,667,668],{},"COMMIT"," 使所有更新永久生效。",[29,671,672,673,676],{},"回滚：事务失败或主动撤销，使用 ",[66,674,675],{},"ROLLBACK"," 撤销所有未提交更新。",[14,678,679],{},"讲解：提交保证持久性，回滚保证原子性。一个事务不能只完成一半后把中间状态留在数据库里。",[18,681,683],{"id":682},"_55-在数据库中为什么要有并发","55. 在数据库中为什么要有并发？",[14,685,43],{},[14,687,688],{},"数据库需要并发是因为多个用户和多个应用常常要同时访问数据库。并发可以提高系统吞吐量、改善资源利用率、缩短用户等待时间。",[14,690,691],{},"讲解：并发不是问题本身，未受控制的并发才是问题。DBMS 通过并发控制在效率和一致性之间取得平衡。",[18,693,695],{"id":694},"_56-并发操作会产生几种不一致情况用什么方法避免各种不一致的情况","56. 并发操作会产生几种不一致情况？用什么方法避免各种不一致的情况？",[14,697,43],{},[14,699,700],{},"常见不一致情况：",[26,702,703,706,709,712],{},[29,704,705],{},"丢失修改：两个事务修改同一数据，后写覆盖先写。",[29,707,708],{},"读脏数据：读到其他事务尚未提交且后来回滚的数据。",[29,710,711],{},"不可重复读：同一事务两次读同一数据，中间被其他事务修改。",[29,713,714],{},"不一致分析：统计过程中部分数据被其他事务更新，得到混合状态结果。",[14,716,717],{},"避免方法：",[126,719,720,723,726],{},[29,721,722],{},"使用封锁机制，读加 S 锁、写加 X 锁。",[29,724,725],{},"遵循两段锁协议或严格两段锁协议。",[29,727,728,729,587,732,587,735,738],{},"使用合适隔离级别，如 SQL Server 的 ",[66,730,731],{},"READ COMMITTED",[66,733,734],{},"REPEATABLE READ",[66,736,737],{},"SERIALIZABLE","、快照隔离。",[14,740,741],{},"讲解：不同隔离级别防止的问题不同。考试中若未限定，写“封锁机制和两段锁协议”最稳。",[18,743,745],{"id":744},"_57-叙述数据库中数据的一致性级别","57. 叙述数据库中数据的一致性级别。",[14,747,43],{},[14,749,750],{},"可按封锁协议理解一致性级别：",[126,752,753,756,759],{},[29,754,755],{},"一级封锁协议：事务修改数据前加 X 锁并保持到事务结束，可防止丢失修改。",[29,757,758],{},"二级封锁协议：在一级基础上，读数据前加 S 锁，读完即可释放，可防止读脏数据。",[29,760,761],{},"三级封锁协议：在一级基础上，读数据前加 S 锁并保持到事务结束，可防止不可重复读。",[14,763,764],{},"讲解：一致性级别越高，隔离性越强，但并发度越低。SQL 标准隔离级别与这些封锁协议有对应关系，但具体实现由 DBMS 决定。",[18,766,768],{"id":767},"_58-叙述封锁的概念","58. 叙述封锁的概念。",[14,770,43],{},[14,772,773],{},"封锁是事务在访问某个数据对象前，先向 DBMS 请求对该对象加锁，以限制其他事务对同一对象的访问。访问结束或事务结束后释放锁。",[14,775,776],{},"讲解：封锁的目标是协调并发事务。常见锁类型是 S 锁和 X 锁，常见封锁粒度可以是行、页、表、数据库等。",[18,778,780],{"id":779},"_59-叙述数据库中死锁产生的原因和解决死锁的方法","59. 叙述数据库中死锁产生的原因和解决死锁的方法。",[14,782,43],{},[14,784,785],{},"死锁产生原因：多个事务各自持有一部分锁，同时又等待对方释放锁，形成循环等待。",[14,787,788],{},"解决方法：",[26,790,791,794,797,800],{},[29,792,793],{},"死锁预防：规定统一加锁顺序，或用时间戳策略避免循环等待。",[29,795,796],{},"死锁检测：构造等待图，若出现环则说明死锁。",[29,798,799],{},"死锁解除：选择代价较小的事务回滚，释放其锁。",[29,801,802],{},"超时法：等待超过阈值后主动回滚。",[14,804,805],{},"讲解：两段锁协议可能产生死锁，因此实际 DBMS 通常需要死锁检测和牺牲事务回滚机制。",[18,807,809],{"id":808},"_60-基本的封锁类型有几种试述它们的含义","60. 基本的封锁类型有几种？试述它们的含义。",[14,811,43],{},[14,813,814],{},"基本封锁类型有两种：",[126,816,817,820],{},[29,818,819],{},"共享锁 S：用于读。多个事务可同时对同一对象加 S 锁。",[29,821,822],{},"排他锁 X：用于写。一个事务加 X 锁后，其他事务不能再加 S 锁或 X 锁。",[14,824,825],{},"讲解：记忆口诀：读读可并行，读写和写写互斥。",[18,827,829],{"id":828},"_61-数据库中为什么要有恢复子系统它的功能是什么","61. 数据库中为什么要有恢复子系统？它的功能是什么？",[14,831,43],{},[14,833,834],{},"数据库需要恢复子系统，是因为事务故障、系统故障、介质故障等可能导致数据库不一致或数据丢失。恢复子系统负责在故障后把数据库恢复到正确一致状态。",[14,836,837],{},"功能包括：",[26,839,840,843,846,849],{},[29,841,842],{},"维护日志和检查点。",[29,844,845],{},"支持事务回滚，撤销失败事务。",[29,847,848],{},"系统重启后自动恢复，REDO 已提交事务、UNDO 未提交事务。",[29,850,851],{},"配合备份转储处理介质故障。",[14,853,854],{},"讲解：恢复子系统主要保证事务的原子性和持久性。",[856,857,858],"style",{},"html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":64,"searchDepth":78,"depth":78,"links":860},[861,862,863,864,869,870,871,872,873,874,875,876,877],{"id":20,"depth":78,"text":21},{"id":111,"depth":78,"text":112},{"id":178,"depth":78,"text":179},{"id":299,"depth":78,"text":300,"children":865},[866,867,868],{"id":324,"depth":84,"text":325},{"id":474,"depth":84,"text":475},{"id":522,"depth":84,"text":523},{"id":572,"depth":78,"text":573},{"id":657,"depth":78,"text":658},{"id":682,"depth":78,"text":683},{"id":694,"depth":78,"text":695},{"id":744,"depth":78,"text":745},{"id":767,"depth":78,"text":768},{"id":779,"depth":78,"text":780},{"id":808,"depth":78,"text":809},{"id":828,"depth":78,"text":829},"md",{},"\u002Fsource\u002Fcs\u002Fdb\u002F100+70\u002Fday11-70-48-61",{"title":5,"description":16},"source\u002Fcs\u002Fdb\u002F100+70\u002FDay11-数据库70题-综合48-61","CbGuq7n12RgymuvwXBPEAq_BIxJysqtEZAuow3yQ1fc",1793692175121]