单选题If a unique constraint is defined on column COL1 of table TAB1, what are the characteristics of COL1?（）A COL1 will accept NULL values and can be referenced in another table's foreign key specification.B COL1 will not accept NULL values and cannot be re

Given the following DDL and INSERT statements:CREATE VIEW v1 AS SELECT col1 FROM t1 WHERE col1 > 10; CREATE VIEW v2 AS SELECT col1 FROM v1 WITH CASCADED CHECK OPTION; CREATE VIEW v3 AS SELECT col1 FROM v2 WHERE col1 < 100; INSERT INTO v1 VALUES(5); INSERT INTO v2 VALUES(5); INSERT INTO v3 VALUES(20); INSERT INTO v3 VALUES(100);How many of these INSERT statements will be successful?（）

A.0

B.1

C.2

D.3

The following statements:CREATE TABLE t1 (col1 INT NOT NULL, PRIMARY KEY(col1)); CREATE TABLE t2 (col1 INT NOT NULL, col2 CHAR(1) NOT NULL, PRIMARY KEY (col1, col2), FOREIGN KEY (col1) REFERENCES t1 (col1) ON DELETE CASCADE ON UPDATE RESTRICT); CREATE TABLE t3 (col1 INT NOT NULL, col2 INT NOT NULL, PRIMARY KEY (col1, col2),FOREIGN KEY (col1) REFERENCES t1 (col1) ON DELETE NO ACTION ON UPDATE RESTRICT);INSERT INTO t1 VALUES (1), (2); INSERT INTO t2 VALUES (1, ‘a‘), (1, ‘b‘), (2,‘c‘); INSERT INTO t3 VALUES (1, 100), (2, 200), (2,300);How many rows will be deleted by the following DELETE statement? DELETE FROM t1 WHERE col1= 1;（）

A.4

B.3

C.1

D.0

What type of constraint is used to ensure that each row inserted into the EMPLOYEE table with a value in the WORKDEPT column has a row with a corresponding value in the DEPTNO column of the DEPARTMENT table?（）

A.A check constraint on the EMPLOYEE table

B.A unique constraint on the EMPLOYEE table WORKDEPT column

C.A foreign key reference from the DEPARTMENT tables DEPTNO column to the WORKDEPT column of the EMPLOYEE table

D.A foreign key reference from the EMPLOYEE tables WORKDEPT column to the DEPTNO column of the DEPARTMENT table

Given the following statements:CREATE TABLE tab1 (col1 INT); CREATE TABLE tab2 (col1 INT); CREATE TRIGGER trig1 AFTER UPDATE ON tab1 REFERENCING NEW AS new1 FOR EACH ROW MODE DB2SQL INSERT INTO tab2 VALUES(new1.col1); INSERT INTO tab1 VALUES(2),(3);What is the result of the following query? SELECT count(*) FROM tab2;（）

A.3

B.2

C.1

D.0

Given the following requirements:Create a table named TESTTAB, which has an identity column named ACTIVITYNO. Define the identity column to generate the values for the column by default. Start the values at 10 and increment by 10. Make the identity column unique. Which of the following CREATE statements will successfully create this table?（）

A.CREATE TABLE TESTTAB (ACTIVITYNO SMALLINT NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 10 INCREMENT BY 10), ACTKWD CHAR(6) NOT NULL, ACTDESC VARCHAR(20) NOT NULL, UNIQUE(ACTIVITYNO))

B.CREATE TABLE TESTTAB (ACTIVITYNO SMALLINT NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 10), ACTKWD CHAR(6) NOT NULL, ACTDESC VARCHAR(20) NOT NULL, UNIQUE(ACTNO))

C.CREATE TABLE TESTTAB (ACTIVITYNO SMALLINT NOT NULL GENERATED BY DEFAULT AS IDENTITY (START WITH 10 INCREMENT BY 1), ACTKWD CHAR(6) NOT NULL, ACTDESC VARCHAR(20) NOT NULL, UNIQUE(ACTIVITYNO))

D.CREATE TABLE TESTTAB (ACTIVITYNO SMALLINT NOT NULL GENERATED BY DEFAULT AS IDENTITY (START WITH 10 INCREMENT BY 10), ACTKWD CHAR(6) NOT NULL, ACTDESC VARCHAR(20) NOT NULL, UNIQUE(ACTIVITYNO))

Given the following requirements:Create a table to contain employee data, with a unique numeric identifier automatically assigned when a row is added, has an EDLEVEL column that permits only the values ‘C‘, ‘H‘ and ‘N‘, and permits inserts only when a corresponding value for the employee‘s department exists in the DEPARTMENT table.Which of the following CREATE statements will successfully create this table?（）

A.CREATE TABLE emp ( empno SMALLINT NEXTVAL GENERATED ALWAYS AS IDENTITY, firstname VARCHAR(30) NOT NULL, lastname VARCHAR(30) NOT NULL, workdept CHAR(3) NOT NULL, edlevel CHAR(1), PRIMARY KEY emp_pk (empno), FOREIGN KEY emp_workdept_fk ON (workdept) REFERENCES department (deptno), CHECK edlevel_ck VALUES (edlevel IN (‘C‘,‘H‘,‘N‘)), );

B.CREATE TABLE emp ( empno SMALLINT NOT NULL GENERATED BY DEFAULT AS IDENTITY, firstname VARCHAR(30) NOT NULL, lastname VARCHAR(30) NOT NULL, workdept CHAR(3), edlevel CHAR(1), CONSTRAINT emp_pk PRIMARY KEY (empno), CONSTRAINT emp_workdept_fk FOREIGN KEY (workdept) REFERENCES department (deptno), CONSTRAINT edlevel_ck CHECK edlevel VALUES (‘C‘,‘H‘,‘N‘) );

C.CREATE TABLE emp ( empno SMALLINT NEXTVAL GENERATED BY DEFAULT AS IDENTITY, firstname VARCHAR(30) NOT NULL, lastname VARCHAR(30) NOT NULL, workdept CHAR(3) NOT NULL, edlevel CHAR(1) CHECK IN (‘C‘,‘H‘,‘N‘)), CONSTRAINT emp_pk PRIMARY KEY (empno), CONSTRAINT emp_workdept_fk FOREIGN KEY department (deptno) REFERENCES (workdept) );

D.CREATE TABLE emp ( empno SMALLINT NOT NULL GENERATED BY DEFAULT AS IDENTITY, firstname VARCHAR(30) NOT NULL, lastname VARCHAR(30) NOT NULL, workdept CHAR(3), edlevel CHAR(1), CONSTRAINT emp_pk PRIMARY KEY (empno), CONSTRAINT emp_workdept_fk FOREIGN KEY (workdept) REFERENCES department (deptno), CONSTRAINT edlevel_ck CHECK (edlevel IN (‘C‘,‘H‘,‘N‘)) );