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

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   STATUS ENABLE CONSTRAINT constraint_name;
• E、ALTER TABLE table_name   TURN ON CONSTRAINT constraint_name;

第2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.

第3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;

第4题：

Which statement adds a constraint that ensures the CUSTOMER_NAME column of the CUSTOMERS table holds a value?（）

• A、ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
• B、ALTER TABLE customers MODIFY CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
• C、ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn NOT NULL;
• D、ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn IS NOT NULL;
• E、ALTER TABLE customers MODIFY name CONSTRAINT cust_name_nn NOT NULL;
• F、ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name NOT NULL;

第5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);

第6题：

Examine the following statement that is used to modify the constraint on the SALES table： SQL> ALTER TABLE SALES MODIFY CONSTRAINT pk DISABLE VALIDATE； Which three statements are true regarding the above command（）

• A、The constraint remains valid.
• B、The index on the constraint is dropped.
• C、It allows the loading of data into the table using SQL*Loader.
• D、New data conforms to the constraint， but existing data is not checked
• E、It allows the data manipulation on the table using INSERT/UPDATE/DELETE SQL statements.

第7题：

Note the output of the following query；   SQL> SELECT flashback_archieve_name， status FROM dba_flashback_archieve； FLASHBACK_ARCHIEVE_NAME STATUS FLA1   You executed the following command to enable Flashback Data Archive on the EXCHANGB_PATE table：   ALTER TABLE exchange_rate FLASHBACK ARCHIEVE；   What is the outcome of this command？（）  

• A、 The table uses the default Flashback Data Archive.
• B、 The Flashback Data Archive Is created In the SYSAUX tablespace.
• C、 The Flashback Data Archive is created in the same tablespace where the tables are stored.
• D、 The command generates an error because no flashback Data Archive name is specified and there is no default Flashback Data Achieve.

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第13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

第14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

第15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

第16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 student_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 MODIFY CONSTRAINT stud _ id _pk PRIMARY KEY (student _ id);

第17题：

User A executes the following command to update the TRANS table）  SQL> UPDATE B.trans SET tr_amt=tr_amt+500 WHERE c_code=’C005’；  Before user A issues a COMMIT or ROLLBACK command， user B executes the following command on the TRANS table：   SQl> ALTER TABLE trans MODIFY （tr_type VARCHAR2 （3））；  What would happen in this scenario？（）

• A、The transaction for user A is rolled back.
• B、The ALTER TABLE command modifies the column successfully.
• C、The ALTER TABLE command fails due to the resource being busy.
• D、The ALTER TABLE command waits until user A ends the transaction.

第18题：

You execute the following command toauditdatabase activities：  SQL>AUDITDROP ANY TABLE BY scott BY SESSION WHENEVER SUCCESSFUL；  What is the effect of this command（）

• A、Oneauditrecord is created for every successful DROP TABLE command executed in the session ofSCOTT.
• B、Oneauditrecord is generated for the session when SCOTT grants the DROP ANY TABLE privilege toother users.
• C、One audit record is created for the whole session if user SCOTT successfully drops one or more tablesin his session.
• D、One audit record is created for every session of any other user in which a table owned by SCOTT isdropped successfully.
• E、One audit record is created for every successful DROP TABLE command executed by any user to droptables owned by SCOTT.

第19题：

Examine the following statement that is used to modify the primary key constraint on the SALES table： SQL> ALTER TABLE SALES MODIFY CONSTRAINT pk DISABLE VALIDATE； Which three statements aretrue regarding the above command（）

• A、The constraint remains valid.
• B、The index on the constraint is dropped.
• C、It allows the loading of data into the table using SQL *Loader.
• D、New data conforms to the constraint， but existing data is not checked.
• E、It allows the data manipulation on the table using INSERT/UPDATE/DELETE SQL statements.

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