單項(xiàng)選擇題

Evaluate the set of SQL statements:
CREATE TABLE dept
(deptno NUMBER(2),
dname VARCNAR2(14),
1oc VARCNAR2 (13));
ROLLBACK;
DESCRIBE DEPT
What is true about the set?（）

A. The DESCRIBE DEPT statement displays the structure of the DEPT table.
B. The ROLLBACK statement frees the storage space occupies by the DEPT table.
C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.
D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.

你可能感興趣的試題

單項(xiàng)選擇題

Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table?（）

A. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) NOT NULL CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);
B. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));
C. CREATE TABLE EMP (empno NUMBER(4) ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));
D. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

單項(xiàng)選擇題

You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty.Which statement accomplishes this task?（）

A. ALTER TABLE students   ADD PRIMARY KEY student_id;
B. ALTER TABLE students   ADD CONSTRAINT PRIMARY KEY (student_id);
C. ALTER TABLE students   ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
D. ALTER TABLE students   ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
E. ALTER TABLE students   MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

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Evaluate the set of SQL statements: CREATE TABLE dept (deptno NUMBER(2), dname VARCNAR2(14), 1oc VARCNAR2 (13)); ROLLBACK; DESCRIBE DEPT What is true about the set?（）

你可能感興趣的試題

Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table?（）

You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty.Which statement accomplishes this task?（）

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Evaluate the set of SQL statements:
CREATE TABLE dept
(deptno NUMBER(2),
dname VARCNAR2(14),
1oc VARCNAR2 (13));
ROLLBACK;
DESCRIBE DEPT
What is true about the set?（）