A database transaction is a unit of work that a database system treats as one coherent operation. Transactions help preserve correct data when operations fail and prevent concurrently running programs from interfering with one another.
A database transaction is a logical unit of work performed against a database. It may contain one operation or several operations that together represent a meaningful change. The database treats the work as a coherent whole rather than as unrelated actions.
All flashcards
What is a database transaction?
A logical unit of work performed against a database and treated as a coherent whole. It can consist of one operation or multiple related operations.
What does ACID stand for?
Atomicity, Consistency, Isolation, and Durability—the four properties commonly used to describe reliable database transactions.
How do atomicity and consistency differ?
Atomicity means all transaction operations take effect or none do. Consistency means a completed transaction obeys the database's rules and constraints, moving the database between valid states.
What is a distributed transaction?
A transaction that accesses data across multiple nodes or systems. A coordinating entity typically manages the participating systems so the transaction's work is applied across them.
What is the difference between a nested transaction and a multi-level transaction?
A nested transaction contains sub-transactions. A multi-level transaction is a related form whose sub-transactions take place at different levels of a layered system architecture.
Quiz questions
What characterizes a transactional database management system?Answer: It provides ACID behavior for a bounded set of operations.
What does a nested transaction contain?Answer: Statements that start sub-transactions.
What distinguishes a multi-level transaction from a nested transaction?Answer: Its sub-transactions operate at different levels of a layered system architecture.
What is the typical role of a coordinator in a distributed transaction?Answer: Manage the transaction across its participating systems.
What does Storage as a Service (StaaS) provide?Answer: Access to storage resources and cloud data stores.