What is the role of the 'rollback' statement in transaction management?
- Committing the changes made by the current transaction
- Ending the current transaction
- Initiating a new transaction
- Reversing the changes made by the current transaction
The 'rollback' statement in transaction management is used to undo the changes made by the current transaction. If an error occurs or a condition is met, the 'rollback' command ensures that all changes made so far in the transaction are rolled back, maintaining data consistency.
The isolation level that allows neither dirty reads nor non-repeatable reads is called _________.
- Read Committed
- Read Uncommitted
- Repeatable Read
- Serializable
The Serializable isolation level ensures neither dirty reads nor non-repeatable reads, providing the highest level of isolation.
The concept of ________ allows multiple users to make changes to the database without affecting each other.
- Concurrency Control
- Consistency Management
- Isolation
- Transaction Control
The concept of Concurrency Control allows multiple users to make changes to the database concurrently without affecting each other, ensuring data integrity and consistency.
In a distributed system, when two databases must be updated as part of a single transaction, which transaction management technique is most appropriate?
- Isolation (I)
- Optimistic Concurrency Control (OCC)
- Pessimistic Concurrency Control (PCC)
- Two-Phase Commit (2PC)
The Two-Phase Commit (2PC) is most appropriate for managing transactions in a distributed system involving updates to multiple databases, ensuring atomicity and consistency across the distributed environment.
What type of exception is commonly thrown when there is a problem with a SQL query in Java?
- ClassNotFoundException
- IOException
- NullPointerException
- SQLException
A SQLException is commonly thrown when there is a problem with a SQL query in Java. It represents a database access error or other errors related to database operations.
Which Java statement is used for handling SQL exceptions?
- finally
- if-else
- switch
- try-catch
The try-catch statement is used for handling SQL exceptions in Java. It allows you to catch and handle specific exceptions that may occur during the execution of the code.
What is the main purpose of using try-catch blocks in database operations?
- To close connections
- To create databases
- To execute SQL queries
- To handle exceptions
The main purpose of using try-catch blocks in database operations is to handle exceptions that may occur during the execution of SQL queries or other database-related operations.
Which method is used to retrieve detailed information about an SQL exception?
- getErrorCode()
- getMessage()
- getSQLException()
- getSQLState()
The getErrorCode() method is used to retrieve the specific error code associated with an SQL exception, providing detailed information about the exception.
How can you handle a situation where a database connection is lost during a transaction?
- Commit the transaction
- Ignore the issue and proceed
- Retry the transaction
- Rollback the transaction
If a database connection is lost during a transaction, you can handle it by retrying the transaction, allowing for the re-establishment of the connection and completion of the operation.
What is the significance of the finally block in JDBC operations?
- To handle exceptions
- To improve performance
- To optimize code execution
- To release resources
The finally block in JDBC operations is significant for releasing resources, ensuring that resources like database connections are properly closed, regardless of whether an exception occurs.