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25 Oracle Certification Questions And Answers

1⟩ Explain When does a transaction complete? (Choose all that apply.) A. When a DELETE statement is executed B. When a ROLLBACK command is executed C. When a PL/SQL anonymous block is executed D. When a data definition language statement is executed E. When a TRUNCATE statement is executed after the pending transaction

B. When a ROLLBACK command is executed

D. When a data definition language statement is executed

E. When a TRUNCATE statement is executed after the pending transaction

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2⟩ what is the difference between TRUNCATE, DELETE, DROP?

1) Drop will drop the records from the table along with its structure.All the indexes associated with it will also deleted and there is no rollback.

2) Delete will deletes the records of the table but the structure of the table is retained back.It is a DML operation which is slower but provides rollback facility.

3) Truncate is a DDL command which is faster ,retain structure of the table and rollback is possible.It allocates memory usually after truncating so structure is retained.

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3⟩ How to create a multiple databases with the same configuration?

Applications can create multiple databases with in a single file.This is useful when database are both numerous and reasonably small in order to avoid creating a large number of underlying files.Putting multiple databases in a single physical file is an administrative convenience and unlikely to affectdatabase performance.

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4⟩ Explain Which two statements are true regarding working with dates? (Choose two.) A. The default internal storage of dates is in the numeric format B. The default internal storage of dates is in the character format C. The RR date format automatically calculates the century from the SYSDATE function and does not allow the user to enter the century D. The RR date format automatically calculates the century from the SYSDATE function but allows the user to enter the century if required?

A. The default internal storage of dates is in the numeric format

D. The RR date format automatically calculates the century from the SYSDATE function but allows

the user to enter the century if required

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5⟩ Suppose you need to generate a list of all customer last names with their credit limits from the CUSTOMERS table. Those customers who do not have a credit limit should appear last in the list. Which two queries would achieve the required result? (Choose two.) A. SELECT cust_last_name,cust_credit_limit FROM customers ORDER BY cust_credit_limit DESC; B. SELECT cust_last_name,cust_credit_limit FROM customers ORDER BY cust_credit_limit; C. SELECT cust_last_name,cust_credit_limit FROM customers ORDER BY cust_credit_limit NULLS LAST; D. SELECT cust_last_name,cust_credit_limit FROM customers ORDER BY cust_last_name,cust_credit_limit NULLS LAST;

B. SELECT cust_last_name,cust_credit_limit

FROM customers

ORDER BY cust_credit_limit;

C. SELECT cust_last_name,cust_credit_limit

FROM customers

ORDER BY cust_credit_limit NULLS LAST;

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6⟩ Which two statements are true regarding views? (Choose two.) A. A subquery that defines a view cannot include the GROUP BY clause B. A view is created with the subquery having the DISTINCT keyword can be updated C. A view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updated D. A Data Manipulation Language (DML) operation can be performed on a view that is created with the subquery having all the NOT NULL columns of a table

C. A view that is created with the subquery having the pseudo column ROWNUM keyword cannot

be updated

D. A Data Manipulation Language (DML) operation can be performed on a view that is created

with the subquery having all the NOT NULL columns of a table

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7⟩ Explain Which two statements are true regarding views? (Choose two.) A. A subquery that defines a view cannot include the GROUP BY clause B. A view is created with the subquery having the DISTINCT keyword can be updated C. A view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updated D. A Data Manipulation Language (DML) operation can be performed on a view that is created with the subquery having all the NOT NULL columns of a table

C. A view that is created with the subquery having the pseudo column ROWNUM keyword cannot

be updated

D. A Data Manipulation Language (DML) operation can be performed on a view that is created

with the subquery having all the NOT NULL columns of a table

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8⟩ Explain Which statements are correct regarding indexes? (Choose all that apply.) A. When a table is dropped, the corresponding indexes are automatically dropped B. A FOREIGN KEY constraint on a column in a table automatically creates a nonunique key C. A nondeferrable PRIMARY KEY or UNIQUE KEY constraint in a table automatically creates a unique index D. For each data manipulation language operation performed, the corresponding indexes are automatically updated

A. When a table is dropped, the corresponding indexes are automatically dropped

C. A nondeferrable PRIMARY KEY or UNIQUE KEY constraint in a table automatically creates a

unique index

D. For each data manipulation language operation performed, the corresponding indexes are

automatically updated

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9⟩ Explain Which two statements are true about sequences created in a single instance database? (Choose two.) A. The numbers generated by a sequence can be used only for one table B. DELETE <sequencename> would remove a sequence from the database C. CURRVAL is used to refer to the last sequence number that has been generated D. When the MAXVALUE limit for a sequence for reached, you can increase the MAXVALUE limit by using the ALTER SEQUENCE statement E. When a database instance shuts down abnormally, the sequence numbers that have been cached but not used would be available once again when the database instance is restarted

C. CURRVAL is used to refer to the last sequence number that has been generated

D. When the MAXVALUE limit for a sequence for reached, you can increase the MAXVALUE limit

by using the ALTER SEQUENCE statement

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10⟩ Explain Which two statements are true regarding constraints? (Choose two.) A. A foreign key cannot contain NULL values B. A columns with the UNIQUE constraint can contain NULL values C. A constraint is enforced only for the INSERT operation on a table D. A constraint can be disabled even if the constraint column contains data E. All constraints can be defined at the column level as well as the table level

B. A columns with the UNIQUE constraint can contain NULL values

D. A constraint can be disabled even if the constraint column contains data

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13⟩ Evaluate the following SQL statements DELETE FROM sales; There are no other uncommitted transactions on the SALES table. Which statement is true about the DELETE statement? A. It would not remove the rows if the table has a primary key B. It removes all the rows as well as the structure of the table C. It removes all the rows in the table and deleted rows can be rolled back D. It removes all the rows in the table and deleted rows cannot be rolled back

C. It removes all the rows in the table and deleted rows can be rolled back

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14⟩ Explain Which two statements are true regarding single row functions? (Choose two.) A. They accept only a single argument B. They can be nested only to two levels C. Arguments can only be column values or constant D. They always return a single result row for every row of a queried table E. They can return a data type value different from the one that is reference

D. They always return a single result row for every row of a queried table

E. They can return a data type value different from the one that is reference

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16⟩ What is row chaining and row migration?

We will migrate a row when an update to that row would cause it to not fit on the block anymore (with all of the other data that exists there currently). A migration means that the entire row will move and we just leave behind the. So, the original block just has the rowid of the new block and the entire row is moved.

Row chaining nstead of just having a forwarding address on one block and the data on another we have data on two or more blocks.

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17⟩ Explain Which three statements are true regarding the data types in Oracle Database 10g/11g? (Choose two.) A. Only One LONG column can be used per table B. A TIMESTAMP data type column stores only time values with fractional seconds C. The BLOB data type column is used to store binary data in an operating system file D. The minimum column width that can be specified for a VARCHAR2 data type column is one E. The value for a CHAR data type column is blanked-padded to the maximum defined column width

A. Only One LONG column can be used per table

D. The minimum column width that can be specified for a VARCHAR2 data type column is one

E. The value for a CHAR data type column is blanked-padded to the maximum defined column

width

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20⟩ You need to calculate the number of days from 1st Jan 2007 till date Dates are stored in the default format of dd-mm-rr. Which two SQL statements would give the required output? (Choose two.) A. SELECT SYSDATE - 01-JAN-2007 FROM DUAL B. SELECT SYSDATE - TO_DATE(01/JANUARY/2007) FROM DUAL; C. SELECT SYSDATE - TO_DATE(01-JANUARY-2007) FROM DUAL; D. SELECT TO_CHAR(SYSDATE,DD-MON-YYYY)-01-JAN-2007 FROM DUAL; E. SELECT TO_DATE(SYSDATE,DD/MONTH/YYYY)-01/JANUARY/2007 FROM DUAL;

B. SELECT SYSDATE - TO_DATE('01/JANUARY/2007') FROM DUAL;

C. SELECT SYSDATE - TO_DATE('01-JANUARY-2007) FROM DUAL;

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