Any action that reads from or writes to a database
What is a transaction
100
Coordinating the simultaneous execution of transactions in a multiuser database system.
What is concurrency control?
100
Indicates the level of lock use.
What is Lock granularity?
100
The approach to scheduling concurrent transactions that assigns a global, unique timestamp to each transaction.
What is timestamping?
100
The assumption that the majority of database operations do not conflict.
What is the optimistic approach?
200
When all data integrity constraints are satisfied.
What is a consistent database state.
200
This occurs when two concurrent transactions are updating the same data element and one of the updates is lost (overwritten by the other transaction).
What is lost update?
200
A technique where a transaction requesting a new lock is aborted when there is the possibility that a deadlock can occur.
What is Deadlock Prevention?
200
Two properties of a timestamp.
What are uniqueness and monotonicity?
200
This restores a database from a given state.
What is database recovery?
300
A transaction property that requires that all operations of a transaction be completed or else the transaction is aborted.
What is Atomicity
300
This occurs when two transactions are executed concurrently and the first transaction is rolled back after the second transaction has already accessed the uncommitted data.
What is the phenomenon of uncommitted data?
300
When the DBMS periodically tests the database for deadlocks.
What is Deadlock Detection
300
ensures that no equal timestamp values can exist.
What is uniqueness?
300
This ensures that transaction logs are always written before any database data are actually updated.
What is write-ahead-log protocol?
400
A transaction property that means that the data used during the execution of a transaction cannot be used by a second transaction until the first one is completed
What is Isolation
400
This occurs when a transaction accesses data before and after one or more other transactions finish working with such data.
What is Inconsistent retrievals?
400
When the transaction must obtain all of the locks it needs before it can be executed. This technique avoids the rolling back of conflicting transactions by requiring that locks be obtained in succession.
What is Deadlock Avoidance?
400
ensures that timestamp values always increase.
What is monotonicity?
400
Temporary storage areas in primary memory used to speed up disk operations.
What are database buffers?
500
Transaction property that ensures that the schedule for the concurrent execution of the transactions yields consistent results.
What is Serializability
500
A special DBMS process that establishes the order in which the operations are executed within concurrent transactions.
What is the scheduler?
500
When tow transactions wait indefinitely for each other to unlock data.
What is a deadly embrace?
500
When the older transaction waits for the younger one to complete and release its locks.
What is wait/die scheme (the other scheme is the wound wait scheme)?
500
Operations in which the DBMS writes all of its updated buffers to disk. While this is happening, the DBMS does not execute any other request.