Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.
Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).
Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.
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.
第1题：
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.
第2题：
A.Check
B.Range
C.Referential
D.Informational
第3题：
A. Column definitions cannot be altered to add DEFAULT values.
B. A change to the DEFAULT value affects only subsequent insertions to the table.
C. Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.
D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.
第4题：
Which of the following can be used to ensure that once a row has been inserted in table TABLEX, the column MAINID in that row cannot be updated?（）
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?（）
第6题：
A.Define the column MAINID as NOT UPDATABLE
B.Define the column MAINID as a PRIMARY KEY
C.Define the column MAINID as a FOREIGN KEY
D.Define an UPDATE trigger on table TABLEX
第7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?（）
第8题：
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
第9题：
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?（）
第10题：
When defining a referential constraint between the parent table T2 and the dependent table T1, which of the following is true?（）