Database Modeling and Design MCQs with Answers
Practice important Database Modeling and Design MCQs with answers and explanations.
Multiple Choice Questions
Q301: Which SQL statement retrieves the next value from a sequence named `customers_seq`?
- A: SELECT customers_seq.nextval FROM dual;
- B: SELECT customers_seq.currval FROM dual;
- C: SELECT * FROM user_sequences WHERE sequence_name = 'customers_seq';
- D: SELECT nextval FROM customers_seq;
View Answer
A
Q302: How do you drop a sequence named `mySeq` in Oracle?
- A: DROP SEQUENCE mySeq;
- B: DELETE SEQUENCE mySeq;
- C: REMOVE SEQUENCE mySeq;
- D: CLEAR SEQUENCE mySeq;
View Answer
A
Q303: Fill in the blank: A sequence in Oracle generates unique numbers _______. Independently of tables
- A: Based on table data
- B: From user input
- C: By manually setting values
- D:
View Answer
A
Q304: Fill in the blank: The `INCREMENT BY` clause in a sequence determines _______. The interval between sequence numbers
- A: The maximum value of the sequence
- B: The starting value of the sequence
- C: The caching of sequence values
- D:
View Answer
A
Q305: What is the primary purpose of an index in a database?
- A: Finding records quickly
- B: Sorting data alphabetically
- C: Updating records efficiently
- D: Deleting records safely
View Answer
A
Q306: Which of the following statements is true about indexes in databases?
- A: Indexes are built on the entire table.
- B: Indexes are used to find records quickly.
- C: Indexes increase the size of the database file.
- D: Indexes slow down query performance.
View Answer
B
Q307: Indexes are created on one or more columns of a table to:
- A: Increase storage space
- B: Speed up data retrieval
- C: Sort records in descending order
- D: Remove duplicates
View Answer
B
Q308: In the index table structure, which of the following is maintained?
- A: Only the key values
- B: Only the row ID
- C: The key values and row ID
- D: The actual data and row ID
View Answer
C
Q309: To search for a record in a table without an index, the system must:
- A: Sort the data alphabetically
- B: Search every row in the table
- C: Use a pre-sorted index
- D: Table all rows in the table
View Answer
B
Q310: What is the purpose of the CREATE INDEX statement in Oracle?
- A: To delete an existing index
- B: To modify a table structure
- C: To create a new index on a table
- D: To retrieve data from a table
View Answer
C