What is the primary purpose of transaction management in database operations?
- Encrypting data
- Ensuring data consistency
- Managing user permissions
- Optimizing queries
The primary purpose of transaction management is to ensure data consistency by either committing or rolling back changes as a single, atomic operation.
Which SQL statement is used to start a transaction in a database?
- BEGIN TRANSACTION
- COMMIT TRANSACTION
- ROLLBACK TRANSACTION
- START TRANSACTION
The START TRANSACTION statement is used to begin a transaction in a database, marking the starting point for a series of SQL statements to be treated as a single unit.
In what scenarios is CallableStatement preferable over PreparedStatement?
- Executing SQL queries with input parameters
- Handling batch updates
- Handling stored procedure calls
- Optimizing read-only operations
CallableStatement is preferable when dealing with stored procedures as it allows the execution of precompiled SQL queries, making it suitable for scenarios where stored procedures are used.
A PreparedStatement can be optimized by the JDBC driver using __________.
- batch processing
- caching
- connection pooling
- query optimization
A PreparedStatement can be optimized by the JDBC driver using connection pooling, which involves reusing database connections to improve performance.
In a CallableStatement, the method _________ is used to execute a SQL function.
- execute()
- executeFunction()
- executeQuery()
- executeUpdate()
In a CallableStatement, the method executeFunction() is used to execute a SQL function.
To improve performance, a PreparedStatement uses _________ to precompile SQL statements.
- compile()
- precompile()
- prepare()
- prepareStatement()
To improve performance, a PreparedStatement uses the prepareStatement() method to precompile SQL statements.
Which method in a servlet is used by default to handle GET requests?
- doGet()
- doPost()
- init()
- service()
The doGet() method in a servlet is used by default to handle GET requests.
In transaction management, what does the term 'ACID' stand for?
- Advanced Commitment Integration Design
- All Committed in Database
- Association of Commitment in Databases
- Atomicity, Consistency, Isolation, Durability
'ACID' stands for Atomicity, Consistency, Isolation, and Durability, which are the key properties ensuring reliable and secure database transactions.
How does a database ensure data integrity during concurrent transactions?
- ACID properties
- Optimistic concurrency control
- Transactions isolation levels
- Using locks
Databases ensure data integrity during concurrent transactions through transactions isolation levels, which define the visibility of changes made by one transaction to other transactions. These levels include Read Uncommitted, Read Committed, Repeatable Read, and Serializable, each providing a different balance between performance and data consistency.
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.