Please enable JavaScript.
Coggle requires JavaScript to display documents.
Transactions (ACID (Consistency - must transform the DB from one…
Transactions
ACID
-
Isolation - potential effects of incomplete transactions should not be visible to other transactions
-
Durability - effects of committed transactions are permanent and must not be lost because of later failure
an action or series of actions, carried out by a user or application program, which reads or updates DB contents - logical unit of work
-
Concurrency Problems
Inconsistent Analysis - transaction reads several values but the second transaction updates some of them during the execution of the first. (Dirty Read)
Uncommitted Dependency - occurs when one or more transactions can see intermediate results of another transaction before it has committed
Phantom Read - a transaction executes a query that retrieves a distinct set of rows, but when the same query is executed again at a later time the retrieved set of rows contains additional (phantom) rows.
-
-