August 2009
Intermediate to advanced
893 pages
26h 48m
English
Content preview from Database Systems: Concepts, Design and Applications
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12.2. Transaction Concepts
A transaction is a logical unit of work of database processing that includes one or more database access operations. A transaction can be defined as an action or series of actions that is carried out by a single user or application program to perform operations for accessing the contents of the database. The operations can include retrieval, (Read), insertion (Write), deletion and modification. A transaction must be either completed or aborted. A transaction is a program unit whose execution may change the contents of a database. It can either be embedded within an application program or can be specified interactively via a high-level query language such as SQL. Its execution preserves the consistency of the database. ...