Sequence

A sequence is referenced in SQL statements with the NEXTVAL and CURRVAL pseudocolumns, what can be used in the following places?

1) VALUES clause of INSERT statements
2) The SELECT list of a SELECT statement
3) The SET clause of an UPDATE statement

• a. CURRVAL

• The SET clause of an UPDATE statementb. NEXTVAL

• c. Both A & B

• d. None of the above

What is a Sequence with each new sequence number that is generated by a reference to the sequence pseudocolumn called?

• a. CURRVAL

• b. NEXTVAL

• c. Both A & B

• d. None of the above

Which is a database objects from which multiple users can generate unique integers?

• a. Views

• b. Sequences

• c. Synonyms

• d. None of the above

Below a table named P is created. Then a sequence is created. Values are inserted into the table using sequence.

CREATE TABLE P ( ID int, Name varchar(255) );

CREATE SEQUENCE MySequence AS Integer Start with 0 Increment by 1

Insert into P values (NEXT VALUE for MySequence, 'AA');
Insert into P values (NEXT VALUE for MySequence, 'BB');
Insert into P values (NEXT VALUE for MySequence, 'CC');

Insert into P values (NEXT VALUE for MySequence, 'AA');
Insert into P values (NEXT VALUE for MySequence, 'BB');
Insert into P values (NEXT VALUE for MySequence, 'CC');

Select * from P;

What will be the values in table P?

• 
• 
• 
• 

The . . . . . . . clause specifies that the object should restart from the minimum value when its maximum value is exceeded.

• A) Restart
  
  

• B) MIN_MAX
  

• C) CYCLE
  

• D) None of above

Sequence gives you guarantee that you won't have gaps.

• True

• False

The default data type for a sequence object is . . . . . .

• A) int
  

• B) bigint
  

• C) tinyint
  

• D) decimal

Sequence objects can be used as an optional way to generate unique numeric values in a table.

• A) True
  

• B) False

Sequence numbers are generated outside the scope of transactions; they are . . . . . . . . . . . whether the transaction is committed or rolled back.

• A) not consumed
  

• B) consumed

Sequence objects are not part of any table definition. They can be used across multiple tables.

• A) True
  

• B) False