51. Which of the following is a DML command?
A) CREATE
B) DROP
C) INSERT
D) ALTER
Answer: C
Which command is used to update existing data?
A) MODIFY
B) CHANGE
C) UPDATE
D) EDIT
Answer: C
A database table consists of:
A) Rows only
B) Columns only
C) Rows and columns
D) Files only
Answer: C
Which key can have NULL values?
A) Primary Key
B) Candidate Key
C) Foreign Key
D) Composite Key
Answer: C
Which normal form removes partial dependency?
A) 1NF
B) 2NF
C) 3NF
D) BCNF
Answer: B
Which normal form removes transitive dependency?
A) 1NF
B) 2NF
C) 3NF
D) 4NF
Answer: C
Normalization is used to:
A) Increase redundancy
B) Decrease redundancy
C) Delete data
D) Store data
Answer: B
Which anomaly occurs due to redundancy?
A) Update anomaly
B) Delete anomaly
C) Insert anomaly
D) All of these
Answer: D
Which operation combines rows from two tables?
A) SELECT
B) JOIN
C) DELETE
D) INSERT
Answer: B
Which JOIN returns matching records only?
A) LEFT JOIN
B) RIGHT JOIN
C) INNER JOIN
D) FULL JOIN
Answer: C
Which JOIN returns all records from left table?
A) LEFT JOIN
B) RIGHT JOIN
C) INNER JOIN
D) CROSS JOIN
Answer: A
Which JOIN returns all records from both tables?
A) FULL JOIN
B) INNER JOIN
C) LEFT JOIN
D) RIGHT JOIN
Answer: A
Which clause filters records?
A) ORDER BY
B) GROUP BY
C) WHERE
D) HAVING
Answer: C
ORDER BY is used to:
A) Filter data
B) Sort data
C) Delete data
D) Insert data
Answer: B
GROUP BY is used to:
A) Sort data
B) Group records
C) Delete data
D) Update data
Answer: B
HAVING clause is used with:
A) SELECT
B) WHERE
C) GROUP BY
D) INSERT
Answer: C
Which function counts rows?
A) SUM()
B) COUNT()
C) AVG()
D) MAX()
Answer: B
Which function finds average?
A) SUM()
B) AVG()
C) COUNT()
D) MIN()
Answer: B
Which function finds maximum value?
A) MAX()
B) MIN()
C) SUM()
D) AVG()
Answer: A
Which function finds minimum value?
A) MAX()
B) MIN()
C) COUNT()
D) SUM()
Answer: B
Which clause eliminates duplicates?
A) UNIQUE
B) DISTINCT
C) GROUP
D) FILTER
Answer: B
Which operator is used for pattern matching?
A) LIKE
B) IN
C) BETWEEN
D) EXISTS
Answer: A
Which operator checks range?
A) LIKE
B) IN
C) BETWEEN
D) EXISTS
Answer: C
Which operator checks list values?
A) IN
B) LIKE
C) BETWEEN
D) JOIN
Answer: A
Which constraint ensures referential integrity?
A) PRIMARY KEY
B) FOREIGN KEY
C) UNIQUE
D) CHECK
Answer: B
Referential integrity ensures:
A) Valid relationship
B) Data duplication
C) Data deletion
D) Data insertion
Answer: A
Which level hides complexity?
A) Internal
B) External
C) Conceptual
D) Physical
Answer: B
Which DBMS architecture level shows entire database?
A) Internal
B) External
C) Conceptual
D) Physical
Answer: C
Which model stores objects?
A) Relational
B) Hierarchical
C) Object-oriented
D) Network
Answer: C
Which database uses tables?
A) Object
B) Relational
C) Network
D) Hierarchical
Answer: B
Which of the following is a NoSQL database?
A) MySQL
B) Oracle
C) MongoDB
D) PostgreSQL
Answer: C
NoSQL databases are:
A) Structured
B) Unstructured
C) Relational
D) Tabular
Answer: B
Which DBMS is open-source?
A) Oracle
B) MySQL
C) SQL Server
D) IBM DB2
Answer: B
Which DBMS is developed by Microsoft?
A) MySQL
B) Oracle
C) SQL Server
D) PostgreSQL
Answer: C
Which DBMS is developed by Oracle Corporation?
A) Oracle DB
B) SQL Server
C) MySQL
D) SQLite
Answer: A
Which of the following is file-based database?
A) SQLite
B) Oracle
C) SQL Server
D) PostgreSQL
Answer: A
Which SQL command gives permission?
A) GRANT
B) REVOKE
C) DENY
D) ALLOW
Answer: A
Which SQL command removes permission?
A) GRANT
B) REVOKE
C) DELETE
D) REMOVE
Answer: B
Transaction means:
A) Single operation
B) Group of operations
C) Data deletion
D) Data insertion
Answer: B
Which property ensures all operations complete?
A) Atomicity
B) Consistency
C) Isolation
D) Durability
Answer: A
Which property ensures correct data?
A) Atomicity
B) Consistency
C) Isolation
D) Durability
Answer: B
Which property ensures transactions are independent?
A) Atomicity
B) Consistency
C) Isolation
D) Durability
Answer: C
Which property ensures permanent storage?
A) Atomicity
B) Consistency
C) Isolation
D) Durability
Answer: D
ACID properties are used in:
A) Security
B) Transactions
C) Backup
D) Queries
Answer: B
Which command saves transaction?
A) COMMIT
B) SAVE
C) STORE
D) APPLY
Answer: A
Which command cancels transaction?
A) CANCEL
B) STOP
C) ROLLBACK
D) UNDO
Answer: C
Which command creates save point?
A) SAVEPOINT
B) SAVE
C) STORE
D) BACKUP
Answer: A
Which of the following is a view?
A) Virtual table
B) Real table
C) Physical table
D) Backup table
Answer: A
Index is used for:
A) Speeding search
B) Deleting data
C) Inserting data
D) Updating data
Answer: A
100. Which improves query performance?
A) Index
B) View
C) Table
D) Record
Answer: A