Database Design and Awesomeness CH 10

The equivalent of a single SQL statement in an application program or transaction.

All parts of a transaction must be treated as a single logical unit of work in which all operations must be completed.

Permanence of database’s consistent state.

Data used during transaction cannot be used by second transaction until the first is completed.

Once transactions are committed, they cannot be undone.

Concurrent execution of several transactions yields consistent results.

A record that records the beginning of the transaction, type of operation being performed, names of objects affected, and other information.

What happens when two concurrent transactions update same data element and one transaction overwrites the other?

Guarantees exclusive use of a data item to a current transaction.

Indicates level of lock use.

A lock that has two states: locked (1) or unlocked (0)

Access is specifically reserved for transaction that locked object.

Concurrent transactions are granted read access on basis of a common lock.

Condition that occurs when two transactions wait for each other to unlock data.

Older transaction waits and younger is rolled back and rescheduled.

Older transaction rolls back younger transaction and reschedules it.