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.
The CallableStatement method _________ is used to get the result set of a stored procedure.
- executeQuery()
- getCallResult()
- getProcedureResult()
- getResultSet()
The CallableStatement method getResultSet() is used to get the result set of a stored procedure.
A developer needs to insert multiple rows into a database efficiently. Which statement type and technique should they use?
- Batch processing using PreparedStatement
- Individual inserts using Statement
- Stored Procedure with Cursor
- Trigger for each row
Batch processing using a PreparedStatement is an efficient way to insert multiple rows into a database as it reduces the number of database round-trips. It allows the developer to group multiple SQL statements and execute them as a batch.
A transaction in a financial application requires updating multiple accounts. If one update fails, what should happen to ensure data consistency?
- Commit the successful updates
- Ignore the failed update and proceed
- Log the failure and retry the update
- Rollback the entire transaction
In a financial application, to ensure data consistency, it's crucial to rollback the entire transaction if any update within it fails. This helps maintain the integrity of the financial data.
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.
What is the difference between 'dirty read' and 'non-repeatable read' in the context of transaction isolation levels?
- Dirty read: Reading committed data
- Dirty read: Reading uncommitted data
- Non-repeatable read: Reading committed data
- Non-repeatable read: Reading uncommitted data
In the context of transaction isolation levels, a 'dirty read' occurs when a transaction reads uncommitted data from another transaction, while a 'non-repeatable read' happens when a transaction reads data committed by another transaction but the data changes before the first transaction completes. Understanding these concepts is crucial in managing data consistency and isolation in concurrent transactions.