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你发出命令：DROP TABLE emp；此时你还没有明确发出COMMIT命令。你能用什么命令撤消上面的drop语句所做的操作（）
- A、关闭数据库
- B、什么命令都不可以，因为DDL语句不能被回滚
- C、发出一个ROLLBACK命令
- D、终断正在活动的会话
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更多 “你发出命令：DROP TABLE emp；此时你还没有明确发出COMMIT命令。你能用什么命令撤消上面的drop语句所做的操作（）A、关闭数据库B、什么命令都不可以，因为DDL语句不能被回滚C、发出一个ROLLBACK命令D、终断正在活动的会话” 相关考题
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删除表S中字段C的SQL命令是（ ）。A.ALTER TABLE s DELETE cB.ALTER TABLE s DROP c．C.DELETE TABLE s DELETE cD.DELETE TABLE s DROP c
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若要删除职工表中的职称字段，应该使用的命令是( )。A．ALTER TABLE 职工 DROP 职称B．ALTER 职工 DROP 职称C．DROP TABLE 职称D．DROP 职称
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删除表s中字段c的SQL命令是A．ALTER TABLE s DELETE cB．ALTER TABLE s DROP cC．DELETE TABLE s DELETE cD．DELETE TABLE s DROP c
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下列哪个操作可以将表中的数据删除,并且不需要回滚删除后回收其所占有的空间,但表定义保留()
A.DELETE FROM EMP;B.TUNCATE TABLE EMP;C.TUNCATE TABLE EMP REUSE STORAGE;D.DROP TABLE EMP;E.以上所述都不正确
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你要操纵Oracle数据，下列哪个不是SQL命令？（）A、select*from dual；B、set defineC、update emp set ename=6543where ename=‘SMITHERS’；D、create table employees（empid varchar2（10）primary key）；
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删除emp表中所有数据，且无法rollback，以下语句哪个命令可以实现（）A、truncate table empB、drop table empC、delete * from empD、delete from emp
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在基表S中删除电话号码（PHONE）属性使用（）命令。A、ALTER S DROP PHONEB、ALTER TABLE S DROP PHONEC、UPDATE TABLE S PHONED、DROP TABLE S PHONE
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您需要从方案中的雇员表中删除EMP_FK_DEPT约束条件。应使用哪条语句（）A、DROP CONSTRAINT EMP_FK_DEPT FROM雇员B、DELETE CONSTRAINT EMP_FK_DEPT FROM雇员C、ALTER TABLE雇员DROP CONSTRAINT EMP_FK_DEPTD、ALTER TABLE雇员REMOVE CONSTRAINT EMP_FK_DEPT
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下列哪个操作可以将表中的数据删除，并且不需要回滚删除后回收其所占有的空间，但表定义保留（）A、DELETE FROM EMP;B、TUNCATE TABLE EMP;C、TUNCATE TABLE EMP REUSE STORAGE;D、DROP TABLE EMP;E、以上所述都不正确
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Examine the following commands executed in your database： SQL ALTER SESSION RECYCLEBIN=ON； Session altered SQL CREATE TABLE emp TABLESPACE tbsfd AS SELECT * FROM hr.employees； Table created. Further， you executed the following command to drop the table： SQL DROP TABLE emp；Table dropped. What happens in this scenario？（）A、The table is moved to the SYSAUX tablespace.B、The table is moved to the SYSTEM tablespace.C、The table is removed from the database permanently.D、The table is renamed and remains in the TBSFD tablespace.
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考题
单选题在基表S中删除电话号码（PHONE）属性使用（）命令。A
ALTER S DROP PHONEB
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考题
单选题请思考以下场景。你在3个不同的模式（SYSIBM、DEFAULT和DB2INST1）下有3个名称相同（TABLE_1）的表。你以db2inst1身份连接到Linux服务器上的DB2数据库并立即发出下列语句：（）。 SELECT * FROM table_1A
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考题
单选题发出下列语句：alter table sales drop columm profit；何时从Oracle中实际删除列？（）A
执行语句后立即删除B
发出alter table drop unused columns命令之后C
发出alter table set unused columns命令之后D
发出alter table modify命令之后
考题
多选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ in order to populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? （）AYou cannot use the EMP_ID_SEQ sequence to populate the JOB_ID column.BThe EMP_ID_SEQ sequence is invalidated when you modify the EMPLOYEE_ID column.CThe EMP_ID_SEQ sequence is not affected by modifications to the EMPLOYEES table.DAny other column of NUMBER data type in your schema can use the EMP_ID_SEQ sequence.EThe EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEES table.FThe EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEE_ID column.
考题
单选题Examine the following commands executed in your database： SQL ALTER SESSION RECYCLEBIN=ON； Session altered SQL CREATE TABLE emp TABLESPACE tbsfd AS SELECT * FROM hr.employees； Table created. Further， you executed the following command to drop the table： SQL DROP TABLE emp；Table dropped. What happens in this scenario？（）A
The table is moved to the SYSAUX tablespace.B
The table is moved to the SYSTEM tablespace.C
The table is removed from the database permanently.D
The table is renamed and remains in the TBSFD tablespace.
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