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ACID Properties in DBMS

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A Transaction  is a single logical unit of work which accesses and possibly modifies the contents of a database. Transactions access data using read and write operations.  In order to maintain consistency in a database, before and after the transaction, certain properties are followed. These are called  ACID  properties.    Atomicity   By this, we mean that either the entire transaction takes place at once or doesn’t happen at all. There is no midway i.e. transactions do not occur partially. Each transaction is considered as one unit and either runs to completion or is not executed at all. It involves the following two operations.  — Abort : If a transaction aborts, changes made to database are not visible.  — Commit : If a transaction commits, changes made are visible.  Atomicity is also known as the ‘All or nothing rule’.    Consider the following transaction  T  consisting of  T1  and  T2 : Transfer ...