设有学生表student,包含的属性有学号sno、学生姓名sname、性别sex、年龄age、所在专业smajor。基于student表建立视图,其中可更新的视图是()。
A. CREATE VIEW V1 AS SELECT sno,sname FROM student;
B. CREATE VIEW V2(major) AS SELECT DISTINCT(smajor) FROM student;
CREATE VIEW V3(major,scount) AS SELECT smajor,COUNT(*) FROM student GROUP BY smajor;
D. CREATE VIEW V4(sname,sage) AS SELECT sname,age+5 FROM student where sno='101';
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MySQL提供的数据库连接途径不包括()。
A. TCP/IP
B. ODB
C. PIPE
D. JDBC
下面给定的表定义语句中,没有定义的完整性约束是()。CREATETABLEtb_score(snochar(10)NOTNULL,cnochar(6)NOTNULL,gradedouble,CONSTRAINTpk_scPRIMARYKEY(sno,cno));
A. 自定义完整性约束
B. 实体完整性约束
C. 域完整性约束
D. 参照完整性约束
创建表tb_account,并在表上建立触发器,代码如下:CREATETABLEtb_account(numINT,amountDECIMAL(10,2));CREATETRIGGERtr_acctAFTERINSERTONtb_accountFOREACHROWSET@sum=@sum+NEW.amount;以上代码执行成功后,tb_account表上不能再建立的触发器类型是()。
AFTER INSERT
BEFORE INSERT
C. AFTER UPDATE
D. AFTER DELETE
设有学生表student,包含的属性有学号sno、学生姓名sname、性别sex、年龄age、所在专业smajor下列语句正确的是()。
A. SELECT sno, sname FROM student ORDER BY sname Union SELECT sno, sname FROM student WHERE smajor='CS';
B. SELECT sno, sname FROM student WHERE sex=’M’ Union SELECT sno, sname, sex FROM student WHERE smajor='CS';
C. SELECT sno, sname FROM student WHERE sex='M' ORDER BY sname Union SELECT sno, sname FROM student WHERE smajor='CS';
D. SELECT sno, sname FROM student WHERE sex='M' Union SELECT sno, sname FROM student WHERE smajor ='CS' ;