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All the materials they use must beA．recycled.B．inexpensive.C．available in the lab.

All the materials they use must be

A．recycled.

B．inexpensive.

C．available in the lab.

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更多“All the materials they use mus…”相关的问题

第1题

Which constraint can be defined only at the column level？（）

A．UNIQUE

B． NOT NULL

C． CHECK

D． PRIMARY KEY

E． FOREIGN KEY

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第2题

Which of the following constraint types can be used to ensure the value of an INTEGER column references only positive values？（）

A．Unique

B．Check

C．Referential

D．Informational

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第3题

When defining a referential constraint between the parent table T2 and the dependent table T1, which of the following is true？（）

A.The list of column names in the FOREIGN KEY clause can be a subset of the list of column names in the primary key of T2 or a UNIQUE constraint that exists on T2.

B.The list of column names in the FOREIGN KEY clause can be a subset of the list of column names in the primary key of T1 or a UNIQUE constraint that exists on T1.

C.The list of column names in the FOREIGN KEY clause must be identical to the list of column names in the primary key of T2 or a UNIQUE constraint that exists on T2.

D.The list of column names in the FOREIGN KEY clause must be identical to the list of column names in the primary key of T1 or a UNIQUE constraint that exists on T1.

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第4题

Examine the following command:CREATE TABLE （prod_id number（4),Prod_name varchar2 （20),Cate

Examine the following command:CREATE TABLE (prod_id number(4),Prod_name varchar2 (20),Category_id number(30),Quantity_on_hand number (3) INVISIBLE);Which three statements are true about using an invisible column in the PRODUCTS table？（）

A. The %ROWTYPE attribute declarations in PL/SQL to access a row will not display the invisible column in the output.

B. The DESCRIBE commands in SQL *Plus will not display the invisible column in the output.

C. Referential integrity constraint cannot be set on the invisible column.

D. The invisible column cannot be made visible and can only be marked as unused.

E. A primary key constraint can be added on the invisible column.

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第5题

Which of the following scenarios will ensure that the value of the NEXT_STEPNO column in a given row of table TABLEX exists as a value of column STEPNO （usually in another row) in the same table？（）

A.Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.

B.Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).

C.Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.

D.Define column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.

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第6题

What type of constraint can be used to ensure that, in any given row in a table, the value of one column never exceeds the value of another column？（）

A．Check

B．Range

C．Referential

D．Informational

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第7题

Which kind of non-sourced UDF can be created so that it only returns a single value？（）

A．Row

B．Table

C．Scalar

D．Column

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第8题

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

A.CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(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 VARCHAR2(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 VARCHAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

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第9题

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));

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