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多选题A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLE command with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the two effects of this command？（）AIt fails if any existin

题目
多选题
A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLE command with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the two effects of this command？（）
A

It fails if any existing row violates the constraint.

B

It does not validate the existing data in the table.

C

It enables the constraint to be enforced at the end of each transaction.

D

It prevents insert， update， and delete operations on the table while the constraint is in the process of being enabled.

参考答案和解析
正确答案： C,B
解析： 暂无解析
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相似问题和答案

第1题：

Which syntax turns an existing constraint on? ()

A. ALTER TABLE table_name ENABLE constraint_name;

B. ALTER TABLE table_name STATUS = ENABLE CONSTRAINT constraint _ name;

C. ALTER TABLE table_name ENABLE CONSTRAINT constraint _ name;

D. ALTER TABLE table_name TURN ON CONSTRAINT constraint _ name;


参考答案：C

第2题：

Which syntax turns an existing constraint on?（）

  • A、ALTER TABLE table_name   ENABLE constraint_name;
  • B、ALTER TABLE table_name   STATUS = ENABLE CONSTRAINT constraint_name;
  • C、ALTER TABLE table_name   ENABLE CONSTRAINT constraint_name;
  • D、ALTER TABLE table_name   STATUS ENABLE CONSTRAINT constraint_name;
  • E、ALTER TABLE table_name   TURN ON CONSTRAINT constraint_name;

正确答案:C

第3题：

Before a Flashback Table operation, you execute the following command:ALTER TABLE employees ENABLE ROW MOVEMENT;Why would you need this to be executed?()

A. Because row IDs may change during the flashback operation

B. Because the object number changes after the flashback operation

C. Because the rows are retrieved from the recycle bin during the flashback operation

D. Because the table is moved forward and back to a temporary during the flashback opertion


参考答案：A

第4题：

Which syntax turns an existing constraint on?（）

  • A、ALTER TABLE table_name ENABLE constraint_name;
  • B、ALTER TABLE table_name STATUS = ENABLE CONSTRAINT constraint _ name;
  • C、ALTER TABLE table_name ENABLE CONSTRAINT constraint _ name;
  • D、ALTER TABLE table_name TURN ON CONSTRAINT constraint _ name;

正确答案:C

第5题：

On your Oracle 12c database, you invoked SQL *Loader to load data into the EMPLOYEES table in the HR schema by issuing the following command: $> sqlldr hr/hr@pdb table=employees Which two statements are true regarding the command?（）

  • A、It succeeds with default settings if the EMPLOYEES table belonging to HR is already defined in the database.
  • B、It fails because no SQL *Loader data file location is specified.
  • C、It fails if the HR user does not have the CREATE ANY DIRECTORY privilege.
  • D、It fails because no SQL *Loader control file location is specified.

正确答案:A,C

第6题：

删除PRIMARYKEY约束条件及其所有依赖约束条件的语法是什么（）

  • A、ALTER TABLE table_name DROP CONSTRAINT constraint_name CASCADE
  • B、ALTER TABLE table_name DROP CONSTRAINT FOREIGN KEY CASCADE
  • C、DROP CONSTRAINT table_name（constraint_name）
  • D、ALTER TABLE table_name DROP CONSTRAINT constraint_name

正确答案:A

第7题：

A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLEcommand with the ENABLE VALIDATE option to enable the constraint that was disabled.  What are the twoeffects of this command（）

  • A、It fails if any existing row violates the constraint.
  • B、It does not validate the existing data in the table.
  • C、It enables the constraint to be enforced at the end of each transaction.
  • D、It prevents insert， update， and delete operations on the table while the constraint is in the process of beingenabled

正确答案:A,D

第8题：

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 _ 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);


参考答案：D

第9题：

Before a Flashback Table operation, you execute the following command: ALTER TABLE employees ENABLE ROW MOVEMENT; Why would you need this to be executed?（）

  • A、Because row IDs may change during the flashback operation
  • B、Because the object number changes after the flashback operation
  • C、Because the rows are retrieved from the recycle bin during the flashback operation
  • D、Because the table is moved forward and back to a temporary during the flashback opertion

正确答案:A

第10题：

You are working in an online transaction processing (OLTP) environment. You use the FLASHBACKTABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command, the system change number (SCN) was 663571. After flashing back the CUSTOMERS table, you realize that the table is not in the correct state. Now, you need to reverse the effects of the FLASHBACK TABLE command. Which is the fastest and the most efficient option to reverse the effects of the FLASHBACK TABLE command?（）

  • A、Restore the backup control file and open the database with RESETLOGS option.
  • B、Perform point-in-time recovery because flashback cannot be performed again on this table
  • C、Execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571
  • D、Execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

正确答案:D

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