The CUSTOMERS table has these columns:<br /> <img src="https://nimg.ppkao.com/2018-08/yiyu/2018080116294948484.jpg?sign=4a6174a02b11d62c7dec3a7cab677141&t=62d369ee" /><br /> The CUSTOMER_ID column is the primary key for the table.Which two statements find the number of customers? （）..

第1题

[单选题] 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

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第2题

[单选题] 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

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第3题

[] Examine this command: SQL > exec DBMS_STATS.SET_TABLE_PREFS (‘SH’, ‘CUSTOMERS’, ‘PUBLISH’, ‘false’); Which three statements are true about the effect of this command?（） Examine this command: SQL > exec DBMS_STATS.SET_TABLE_PREFS (‘SH’, ‘CUSTOMERS’, ‘PUBLISH’, ‘false’); Which three statements are true about the effect of this command?（）

A、A. Statistics collection is not done for the CUSTOMERS table when schema stats are gathered. B、B. Statistics collection is not done for the CUSTOMERS table when database stats are gathered. C、C. Any existing statistics for the CUSTOMERS table are still available to the optimizer at parse time. D、D. Statistics gathered on the CUSTOMERS table when schema stats are gathered are stored as pending statistics. E、E. Statistics gathered on the CUSTOMERS table when database stats are gathered are stored as pending statistics.

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第4题

[单选题] 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;

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第5题

[单选题] 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;

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第6题

[单选题] 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;

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第7题

[单选题] Examine the command： SQL> DBMS_STATS.SET_TABLE_PREFS（’SH’， ’CUSTOMERS’， ’PUBLISH’， ’false’）； Which statement describes the effect of the above command（）

A、Automatic statistics collection is stopped for the CUSTOMERS table. B、Statistics for the CUSTOMERS table are locked and cannot be overwritten. C、Existing statistics for the CUSTOMERS table become unusable for the query optimizer. D、Subsequently， statistics gathered on the CUSTOMERS table are stored as pending statistics.

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第8题

[] Examine the command： SQL> DBMS_STATS.SET_TABLE_PREFS（’SH’， ’CUSTOMERS’， ’PUBLISH’， ’false’）； Which statementdescribes the effect of the above command（） Examine the command： SQL> DBMS_STATS.SET_TABLE_PREFS（’SH’， ’CUSTOMERS’， ’PUBLISH’， ’false’）； Which statementdescribes the effect of the above command（）

A、A.Automatic statistics collection is stopped for the CUSTOMERS table. B、B.Statistics for the CUSTOMERS table are locked and cannot be overwritten. C、C.Existing statistics for the CUSTOMERS table become unusable for the query optimizer. D、D.Subsequently， statistics gathered on the CUSTOMERS table are stored as pending statistics

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第9题

[单选题] The CUSTOMERS table has these columns: Which statement finds the rows in the CUSTOMERS table that do not have a postal code?（）

A、SELECT customer_id, customer_name FROM customers WHERE postal_code CONTAINS NULL; B、SELECT customer_id, customer_name FROM customers WHERE postal_code = '________'; C、SELECT customer_id, customer_name FROM customers WHERE postal_code IS NULL; D、SELECT customer_id, customer_name FROM customers WHERE postal code IS NVL; E、SELECT customer_id, customer_name FROM customers WHERE postal_code = NULL;

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The CUSTOMERS table has these columns:<br /> <img src="https://nimg.ppkao.com/2018-08/yiyu/2018080116294948484.jpg?sign=4a6174a02b11d62c7dec3a7cab677141&t=62d369ee" /><br /> The CUSTOMER_ID column is the primary key for the table.Which two statements find the number of customers? （）

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