H2 Database MCQs and Answers With Explanation – H2 Database is a popular open-source, in-memory and embedded database management system that is written in Java. It supports a wide range of SQL standards and is compatible with various programming languages such as Java, C++, and Python. If you wish to test your knowledge regarding the H2 Database, then feel free to scroll down and check out this H2 Database Online Quiz.
H2 Database Multiple Choice Questions
H2 Database is known for its speed, reliability, and ease of use, making it a popular choice among developers. In this set of H2 Database MCQ Questions, we will test your knowledge of H2 Database concepts, features, and syntax. These H2 Database MCQs are designed to help you assess your understanding of H2 Database and prepare you for certification exams, job interviews, and real-world scenarios.
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H2 Database MCQ With Answers
| Name | H2 Database |
| Exam Type | MCQ (Multiple Choice Questions) |
| Category | Technical Quiz |
| Mode of Quiz | Online |
Top 50 H2 Database MCQs | Practice Online Quiz
1. What is H2 database?
A) A relational database management system
B) A NoSQL database
C) A distributed data store
D) A file system
Answer: A
Explanation: H2 database is a high-performance, open-source, and relational database management system written in Java.
2. Which of the following statements is true about H2 database?
A) It supports a wide range of SQL standards
B) It supports only basic SQL operations
C) It doesn’t support transactions
D) It doesn’t support indexes
Answer: A
Explanation: H2 database supports a wide range of SQL standards, including SQL-92, SQL-99, and SQL:2003.
3. What is the default mode of operation for H2 database?
A) Server mode
B) Embedded mode
C) Distributed mode
D) Cluster mode
Answer: B
Explanation: The default mode of operation for H2 database is embedded mode, which means that the database is run within the same JVM as the application.
4. Which of the following data types is not supported by H2 database?
A) Boolean
B) Date
C) Time
D) Timestamp with time zone
Answer: D
Explanation: H2 database doesn’t support the Timestamp with time zone data type.
5. What is the default isolation level for transactions in H2 database?
A) READ COMMITTED
B) READ UNCOMMITTED
C) REPEATABLE READ
D) SERIALIZABLE
Answer: A
Explanation: The default isolation level for transactions in H2 database is READ COMMITTED.
6. What is the maximum size of a database file in H2 database?
A) 1 GB
B) 10 GB
C) 100 GB
D) Unlimited
Answer: D
Explanation: There is no maximum size limit for a database file in H2 database.
7. Which of the following statements is true about the H2 Console?
A) It is a command-line tool for managing H2 databases
B) It is a GUI tool for managing H2 databases
C) It is a web-based tool for managing H2 databases
D) H2 doesn’t have a console
Answer: C
Explanation: The H2 Console is a web-based tool for managing H2 databases.
8. Which of the following statements is true about the AUTO_INCREMENT keyword in H2 database?
A) It is used to generate a unique value for a column automatically
B) It is used to create a new table
C) It is used to drop a table
D) H2 doesn’t support AUTO_INCREMENT
Answer: A
Explanation: The AUTO_INCREMENT keyword is used to generate a unique value for a column automatically in H2 database.
9. Which of the following statements is true about H2 database backups?
A) They can be performed while the database is running
B) They can only be performed while the database is offline
C) They require a third-party tool to perform
D) H2 doesn’t support backups
Answer: A
Explanation: H2 database backups can be performed while the database is running.
10. Which of the following statements is true about the H2 database MVStore storage engine?
A) It is the default storage engine used by H2 database
B) It is only available in the commercial version of H2 database
C) It is a NoSQL storage engine
D) It doesn’t support transactions
Answer: A
Explanation: The H2 database MVStore storage engine is the default storage engine used by H2 database.
11. What is the syntax for creating a table in H2 database?
A) CREATE TABLE table_name (column_name column_type, …)
B) CREATE table_name (column_name column_type, …)
C) TABLE table_name (column_name column_type, …)
D) None of the above
Answer: A
Explanation: The syntax for creating a table in H2 database is: CREATE TABLE table_name (column_name column_type, …).
12. What is the syntax for inserting data into a table in H2 database?
A) INSERT INTO table_name (column1, column2, …) VALUES (value1, value2, …)
B) INSERT table_name (column1, column2, …) VALUES (value1, value2, …)
C) INSERT (column1, column2, …) VALUES (value1, value2, …) INTO table_name
D) None of the above
Answer: A
Explanation: The syntax for inserting data into a table in H2 database is: INSERT INTO table_name (column1, column2, …) VALUES (value1, value2, …).
13. What is the syntax for updating data in a table in H2 database?
A) UPDATE table_name SET column1=value1, column2=value2, … WHERE condition
B) UPDATE (column1, column2, …) VALUES (value1, value2, …) IN table_name WHERE condition
C) UPDATE SET column_name = value WHERE table_name
D) None of the above
Answer: A
Explanation: The syntax for updating data in a table in H2 database is: UPDATE table_name SET column1=value1, column2=value2, … WHERE condition.
14. What is the syntax for deleting data from a table in H2 database?
A) DELETE FROM table_name WHERE condition
B) DELETE table_name WHERE condition
C) REMOVE table_name WHERE condition
D) None of the above
Answer: A
Explanation: The syntax for deleting data from a table in H2 database is: DELETE FROM table_name WHERE condition.
15. What is the syntax for creating an index in H2 database?
A) CREATE INDEX index_name ON table_name (column_name)
B) CREATE INDEX index_name (column_name) ON table_name
C) INDEX index_name ON table_name (column_name)
D) None of the above
Answer: A
Explanation: The syntax for creating an index in H2 database is: CREATE INDEX index_name ON table_name (column_name).
16. What is the purpose of the UNIQUE constraint in H2 database?
A) It ensures that all values in a column are unique
B) It ensures that a combination of values in multiple columns is unique
C) It ensures that a column has a non-null value
D) It ensures that a column has a default value
Answer: B
Explanation: The UNIQUE constraint in H2 database ensures that a combination of values in multiple columns is unique.
17. What is the purpose of the NOT NULL constraint in H2 database?
A) It ensures that all values in a column are unique
B) It ensures that a combination of values in multiple columns is unique
C) It ensures that a column has a non-null value
D) It ensures that a column has a default value
Answer: C
Explanation: The NOT NULL constraint in H2 database ensures that a column has a non-null value.
18. What is the purpose of the DEFAULT constraint in H2 database?
A) It ensures that all values in a column are unique
B) It ensures that a combination of values in multiple columns is unique
C) It ensures that a column has a non-null value
D) It specifies a default value for a column
Answer: D
Explanation: The DEFAULT constraint in H2 database specifies a default value for a column.
19. Which command is used to start the H2 database server?
A) h2 start
B) h2 server start
C) java -jar h2.jar server start
D) None of the above
Answer: C
Explanation: The command “java -jar h2.jar server start” is used to start the H2 database server.
20. Which of the following statements is true about H2 database?
A) It is a relational database management system.
B) It is an object-oriented database management system.
C) It is a NoSQL database management system.
D) It is a graph database management system.
Answer: A
Explanation: H2 database is a relational database management system.
21. What is the default port number for H2 database server?
A) 3306
B) 5432
C) 8082
D) 9092
Answer: C
Explanation: The default port number for H2 database server is 8082.
22. Which of the following statements is true about H2 database transactions?
A) H2 database does not support transactions.
B) H2 database supports only read transactions.
C) H2 database supports both read and write transactions.
D) H2 database supports only write transactions.
Answer: C
Explanation: H2 database supports both read and write transactions.
23. What is the syntax for starting a transaction in H2 database?
A) BEGIN TRANSACTION
B) START TRANSACTION
C) COMMIT TRANSACTION
D) None of the above
Answer: B
Explanation: The syntax for starting a transaction in H2 database is: START TRANSACTION.
24. What is the syntax for committing a transaction in H2 database?
A) BEGIN TRANSACTION
B) START TRANSACTION
C) COMMIT TRANSACTION
D) None of the above
Answer: C
Explanation: The syntax for committing a transaction in H2 database is: COMMIT TRANSACTION.
25. Which command is used to connect to a H2 database server using the H2 Console?
A) h2 console
B) h2 connect
C) java -jar h2.jar console
D) None of the above
Answer: A
Explanation: The command “h2 console” is used to connect to a H2 database server using the H2 Console.
26. Which of the following statements is true about H2 database constraints?
A) Constraints are used to limit the type of data that can be inserted into a table.
B) Constraints are used to enforce rules on data in a table.
C) Constraints are used to ensure data consistency.
D) All of the above
Answer: D
Explanation: H2 database constraints are used to limit the type of data that can be inserted into a table, enforce rules on data in a table, and ensure data consistency.
27. Which of the following is a valid H2 database data type?
A) ENUM
B) DATETIME
C) DECIMAL
D) All of the above
Answer: D
Explanation: ENUM, DATETIME, and DECIMAL are all valid H2 database data types.
28. What is the purpose of the AUTO_INCREMENT keyword in H2 database?
A) It specifies a default value for a column.
B) It ensures that a column has a non-null value.
C) It generates a unique value for a column automatically.
D) It enforces a unique constraint on a column.
Answer: C
Explanation: The AUTO_INCREMENT keyword in H2 database generates a unique value for a column automatically.
29. Which of the following is a valid way to create a table in H2 database?
A) CREATE TABLE MyTable (ID INT PRIMARY KEY, Name VARCHAR(255));
B) CREATE TABLE IF NOT EXISTS MyTable (ID INT PRIMARY KEY, Name VARCHAR(255));
C) Both A and B
D) None of the above
Answer: C
Explanation: Both A and B are valid ways to create a table in H2 database.
30. Which of the following is a valid way to insert data into a table in H2 database?
A) INSERT INTO MyTable (ID, Name) VALUES (1, “John”);
B) INSERT INTO MyTable VALUES (1, “John”);
C) Both A and B
D) None of the above
Answer: C
Explanation: Both A and B are valid ways to insert data into a table in H2 database.
31. Which of the following is a valid way to update data in a table in H2 database?
A) UPDATE MyTable SET Name = “Mike” WHERE ID = 1;
B) UPDATE MyTable SET ID = 2 WHERE Name = “Mike”;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to update data in a table in H2 database.
32. Which of the following is a valid way to delete data from a table in H2 database?
A) DELETE FROM MyTable WHERE ID = 1;
B) DROP TABLE MyTable;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to delete data from a table in H2 database.
33. Which of the following is a valid way to drop a table in H2 database?
A) DROP TABLE MyTable;
B) DELETE FROM MyTable;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to drop a table in H2 database.
34. Which of the following is a valid way to add a column to a table in H2 database?
A) ALTER TABLE MyTable ADD COLUMN Email VARCHAR(255);
B) ALTER TABLE MyTable CHANGE COLUMN Name LastName VARCHAR(255);
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to add a column to a table in H2 database.
35. Which of the following is a valid way to change the name of a column in a table in H2 database?
A) ALTER TABLE MyTable RENAME COLUMN Name TO FirstName;
B) ALTER TABLE MyTable MODIFY COLUMN Name FirstName VARCHAR(255);
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to change the name of a column in a table in H2 database.
36. Which of the following is a valid way to change the data type of a column in a table in H2 database?
A) ALTER TABLE MyTable MODIFY COLUMN ID BIGINT;
B) ALTER TABLE MyTable CHANGE COLUMN ID BIGINT;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to change the data type of a column in a table in H2 database.
37. Which of the following is a valid way to create an index in H2 database?
A) CREATE INDEX IDX_Name ON MyTable (Name);
B) CREATE INDEX IF NOT EXISTS IDX_Name ON MyTable (Name);
C) Both A and B
D) None of the above
Answer: C
Explanation: Both A and B are valid ways to create an index in H2 database.
38. Which of the following is a valid way to create a unique index in H2 database?
A) CREATE UNIQUE INDEX IDX_Email ON MyTable (Email);
B) CREATE INDEX IDX_Email UNIQUE ON MyTable (Email);
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a unique index in H2 database.
39. Which of the following is a valid way to create a foreign key in H2 database?
A) ALTER TABLE MyTable ADD CONSTRAINT FK_Employee FOREIGN KEY (DeptID) REFERENCES Departments(DeptID);
B) ALTER TABLE MyTable ADD CONSTRAINT FK_Employee REFERENCES Departments(DeptID);
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a foreign key in H2 database.
40. Which of the following is a valid way to drop a foreign key in H2 database?
A) ALTER TABLE MyTable DROP CONSTRAINT FK_Employee;
B) ALTER TABLE MyTable DROP FOREIGN KEY FK_Employee;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to drop a foreign key in H2 database.
41. Which of the following is a valid way to create a view in H2 database?
A) CREATE VIEW MyView AS SELECT * FROM MyTable WHERE Name LIKE ‘A%’;
B) CREATE TABLE MyView AS SELECT * FROM MyTable WHERE Name LIKE ‘A%’;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a view in H2 database.
42. Which of the following is a valid way to drop a view in H2 database?
A) DROP VIEW MyView;
B) DROP TABLE MyView;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to drop a view in H2 database.
43. Which of the following is a valid way to create a sequence in H2 database?
A) CREATE SEQUENCE MySequence START WITH 1 INCREMENT BY 1;
B) CREATE TABLE MySequence (ID INT PRIMARY KEY, Name VARCHAR(255));
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a sequence in H2 database.
44. Which of the following is a valid way to insert a value generated by a sequence into a table in H2 database?
A) INSERT INTO MyTable (ID, Name) VALUES (NEXT VALUE FOR MySequence, ‘John’);
B) INSERT INTO MyTable (ID, Name) VALUES (MySequence.NEXTVAL, ‘John’);
C) Both A and B
D) None of the above
Answer: B
Explanation: Option B is a valid way to insert a value generated by a sequence into a table in H2 database.
45. Which of the following is a valid way to drop a sequence in H2 database?
A) DROP SEQUENCE MySequence;
B) DROP TABLE MySequence;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to drop a sequence in H2 database.
46. Which of the following is NOT a valid H2 database data type?
A) VARCHAR
B) INTEGER
C) BOOLEAN
D) DECIMAL128
Answer: D
Explanation: DECIMAL128 is not a valid H2 database data type.
47. Which of the following is a valid way to create a user-defined data type in H2 database?
A) CREATE TYPE MyType AS VARCHAR(255);
B) CREATE TYPE MyType FROM VARCHAR(255);
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a user-defined data type in H2 database.
48. Which of the following is a valid way to create a user-defined aggregate function in H2 database?
A) CREATE AGGREGATE MyAggregate FOR “org.example.MyAggregateClass”;
B) CREATE FUNCTION MyAggregate(input VARCHAR(255)) RETURNS VARCHAR(255) SONAME ‘libmyagg.so’;
C) Both A and B
D) None of the above
Answer: A
Explanation: Option A is a valid way to create a user-defined aggregate function in H2 database.
49. Which of the following SQL statements is used to add a new column to an existing table in MySQL?
A) ADD COLUMN
B) ALTER TABLE
C) CREATE TABLE
D) UPDATE
Answer: B
Explanation: The ALTER TABLE statement is used to add or modify columns in an existing table. The syntax for adding a new column is “ALTER TABLE table_name ADD COLUMN column_name data_type;”.
50. Which of the following is NOT a valid data type in PostgreSQL?
A) INTEGER
B) NUMERIC
C) DOUBLE PRECISION
D) DECIMAL
Answer: D
Explanation: PostgreSQL does not have a data type called DECIMAL. Instead, it uses the NUMERIC data type to represent fixed-point decimal numbers with a specified precision and scale.
Our Freshersnow team has compiled the Top 50 H2 Database MCQ With answers that cover a wide range of topics related to the H2 Database, including data types, syntax, and functionality. By answering these H2 Database MCQ Questions, you can improve your understanding of the H2 Database and enhance your skills as a developer or database administrator.