单选题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

题目

单选题

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?（）

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.

更多“单选题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”相关问题

第1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 tableB、A unique constraint on the EMPLOYEE table WORKDEPT columnC、A foreign key reference from the DEPARTMENT tables DEPTNO column to the WORKDEPT column of the EMPLOYEE tableD、A foreign key reference from the EMPLOYEE tables WORKDEPT column to the DEPTNO column of the DEPARTMENT table

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第2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?（）A、Define the column MAINID as NOT UPDATABLEB、Define the column MAINID as a PRIMARY KEYC、Define the column MAINID as a FOREIGN KEYD、Define an UPDATE trigger on table TABLEX

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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

Which two statements are true about constraints? （）A、The UNIQUE constraint does not permit a null value for the column.B、A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.C、The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.D、The NOT NULL constraint ensures that null values are not permitted for the column.

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第5题

Which statement describes the effect on an index， when the indexed column for the rows is updatedin the base table（）A、An update in a leaf row takes place.B、The index becomes invalid after the update.C、The leaf block containing the row to be updated is marked as invalid.D、A row in the leaf block of the index for the key value is logically deleted and a new leaf row is inserted

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第6题

36 You are creating a report wizard to create a matrix report. The query build, you select the patient_name column from the patient table; the doctor_name from the doctors table; and the doctor_ID, patient_ID and ID columns from the procedure table. In the report wizard you select patient_name as the row value, doctor_ID as the column values and the count as the cell values. You need to add a total for each doctors column. In the wizard report which tab will allow you to create the summary column?（）A、Rows B、Totals C、Columns D、Cells E、Data

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第7题

The EMPLOYEES table has these columns: LAST_NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY (SALARY DEFAULT 5000); Which is true about your ALTER statement?（） 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 to 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.

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单选题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

题目

更多“单选题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”相关问题

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