Understanding Query Processing Concepts

What is query processing cost estimation?

• The process of optimizing database storage space.

• A method for securing database queries from unauthorized access.

• The analysis of user behavior in database interactions.

• Query processing cost estimation is the evaluation of the resources needed to execute a database query.

Name two common join strategies used in databases.

• Merge join

• Cross join

• Self join

• Nested loop join, Hash join

What are the key concepts of transaction processing?

• Network security protocols

• Key concepts of transaction processing include ACID properties, concurrency control, and recovery mechanisms.

• Data encryption techniques

• User authentication methods

Define atomicity in the context of transactions.

• Atomicity means transactions can be split into multiple parts.

• Atomicity ensures that a transaction is all-or-nothing.

• Atomicity refers to the speed of transaction processing.

• Atomicity allows partial transactions to be committed.

How does durability ensure data integrity in transactions?

• Durability allows for faster transaction processing, which improves data integrity.

• Durability ensures that committed transactions are permanent and protected from data loss, thus maintaining data integrity.

• Durability prevents unauthorized access to data, ensuring integrity.

• Durability is only relevant for temporary data storage, not for transactions.

What is the purpose of a query execution plan?

• The purpose of a query execution plan is to optimize the execution of a database query by detailing the steps and methods for data retrieval.

• To display the total number of records in a table.

• To provide a summary of the database structure.

• To generate random data for testing purposes.

Explain the difference between inner join and outer join.

• Inner join returns matched rows; outer join returns all rows with NULLs for non-matches.

• Inner join returns all rows; outer join returns only matched rows.

• Inner join includes NULLs for non-matches; outer join does not.

• Inner join and outer join are the same; both return all rows.

What are the states of a transaction during processing?

• Started, Under Review, Finalized

• Queued, In Queue, Delivered

• Processing, In Review, Archived

• Pending, In Progress, Completed, Failed, Cancelled

How can deadlocks be avoided in transaction processing?

• Implement resource ordering, timeout mechanisms, and priority schemes.

• Allow transactions to run indefinitely

• Disable locking mechanisms entirely

• Increase the number of resources available

What role does concurrency control play in transaction management?

• Concurrency control prevents data inconsistencies and ensures data integrity during simultaneous transaction execution.

• Concurrency control allows transactions to execute in any order without restrictions.

• Concurrency control eliminates the need for locking mechanisms in databases.

• Concurrency control is primarily used for data backup and recovery processes.