The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL

 Create a FOR trigger. 

 Create an INSTEAD OF trigger. 

 Create an AFTER trigger. 

 Create a DDL trigger.

Automatic statistics collection is stopped for the CUSTOMERS table.

Statistics for the CUSTOMERS table are locked and cannot be overwritten.

Existing statistics for the CUSTOMERS table become unusable for the query optimizer.

Subsequently， statistics gathered on the CUSTOMERS table are stored as pending statistics

a table name which has 100s of records

a table name which has 10s of records

a table name which has empty records

a table name which has 1000s of records

never use a table name

use the ROLLBACK command with SCN 663571

perform Flashback Transaction Query with SCN 663571

execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571

execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

Automatic statistics collection is stopped for the CUSTOMERS table.

Statistics for the CUSTOMERS table are locked and cannot be overwritten.

Existing statistics for the CUSTOMERS table become unusable for the query optimizer.

Subsequently， statistics gathered on the CUSTOMERS table are stored as pending statistics.

SELECT customer_id, customer_name FROM customers WHERE postal_code CONTAINS NULL;

SELECT customer_id, customer_name FROM customers WHER postal_code = ' ___________';

SELECT customer_id, customer_name FROM customers WHERE postal _ code IS NULL;

SELECT customer_id, customer_name FROM customers WHERE postal code IS NVL;

SELECT customer_id, customer_name FROM customers WHERE postal_code = NULL;

ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;

ALTER TABLE customers MODIFY CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;

ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn NOT NULL;

ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn IS NOT NULL;

ALTER TABLE customers MODIFY name CONSTRAINT cust_name_nn NOT NULL;

ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name NOT NULL;

 Use ROLLBACK command with SCN 663571.

 Perform Flashback Transaction Query with SCN 663571.

 Execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571.

 Execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571.

SELECT* FROM customers;

SELECT name, address FROM customers;

SELECT id, name, address, phone FROM customers;

SELECT cust_name, cust_address FROM customers;

SELECT cust_id, cust_name, cust_address, cust_phone FROM customers;

 The statistics are stored in the pending statistics table in the data dictionary.

 The statistics are treated as the current statistics by the optimizer for all sessions.

 The statistics are treated as the current statistics by the optimizer for the current sessions only.

 The statistics are temporary and used by the optimizer for all sessions until this session terminates.

SELECT*   FROM customers;

SELECT name, address   FROM customers;

SELECT id, name, address, phone   FROM customers;

SELECT cust_name, cust_address   FROM customers;

SELECT cust_id, cust_name, cust_address, cust_phone   FROM customers;

Statistics collection is not done for the CUSTOMERS table when schema stats are gathered.

Statistics collection is not done for the CUSTOMERS table when database stats are gathered.

Any existing statistics for the CUSTOMERS table are still available to the optimizer at parse time.

Statistics gathered on the CUSTOMERS table when schema stats are gathered are stored as pending statistics.

Statistics gathered on the CUSTOMERS table when database stats are gathered are stored as pending statistics.

Restore the backup control file and open the database with RESETLOGS option.

Perform point-in-time recovery because flashback cannot be performed again on this table

Execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571

Execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

if a table is not in a cluster

if a table has an active trigger

if a table has an encrypted

if a table has a column of data type LONG defined on it

if a table has a referential integrity constraint defined on it

The database instance is not available.

The ALTER TABLE command does not have WAIT option

The table or a row in the table is currently locked by another user session.

The database instance is busy processing other user sessions commands.

The CUSTOMERS table has no long running query active at the time when this request is made.

The server process executing the ALTER TABLE command is busy with another command execution

SELECT* FROM customers;

SELECT name, address FROM customers;

SELECT id, name, address, phone FROM customers;

SELECT cust_name, cust_address FROM customers;

SELECT cust_id, cust_name, cust_address, cust_phone FROM customers;