Database infrastructures are an integral part of an enterprise and necessary for ensuring continuous flow of information throughout the enterprise. Database transactions are vital for reducing the risk of failure in an enterprise database and ensure proper functioning. This article discusses some of the aspects associated with database transactions.
What Is Database Transaction?
A database transaction is defined as a unit of work carried out within a Database Management System, which is capable of being identified in a reliable and coherent way, while being independent of other transactions. The main purposes of a database transaction are to enable isolation between different programs concurrently accessing the database as well as to facilitate the availability of reliable units of work, which enable the correct recovery of the database subsequent to a failure. The units of work provided by database transactions help enterprises maintain their data integrity even if a number of database tasks remain pending or incomplete subsequent at the time of database failure.
The transactions are designed such that they either complete a task in its totality or produce no effect if a specific transaction remains incomplete. Moreover, a typical transaction system is designed such that, each transaction is completely isolated from any and all transactions occurring in the database and at the same time, the results obtained from a transaction is required to comply with all restrictions imposed on the database. The major properties of a database transaction or the general rules governing a database transaction are as follows:
This refers to the “all or nothing” feature of a database transaction according to which the changes in a database occur only if a specific transaction is completed and no change in the database occurs if the transaction remains incomplete. The term refers to the fact that a specific transaction appears to be indivisible to an external observer and an aborted transaction leaves behind no trace of its existence.
Each database transaction is required to adhere to any and all rules implemented for maintaining database integrity and minimizing the risk of database failure. Each transaction is thus required to transform the database from one consistent state to another. Offshore Software Development Companies engaged in programming database transaction ensure that such transformation occurs in a consistent manner and performs the correct functions. If a transaction is aborted prior to completion, the database continues to remain in a consistent state as no trace of the aborted transaction would be available in the database.
It is necessary that all database transactions can operate independent of one another, while remaining invisible to one another to facilitate concurrent transactions within the same database. Such isolation is integral to facilitating concurrent control to facilitate accessibility by multiple users.
The records of successful transaction must be accessible even if a database crash occurs. This is achieved by automatically recording the effects produced by the transaction to a non-volatile memory storage unit. This feature ensures that the loss of data following a database crash is little to none even if the database crashes.
The above features of a database transaction are commonly referred by using the acronym ACID, Additional features, which are often provided as part of custom software development services to enhance database integrity include Locking and Concurrency Control.
Locking or two-phase locking is a leading method for initiating concurrency control to facilitate the management of databases. The procedure provides both recoverability and serialization of transaction to facilitate the correctness of databases. The accessibility of a database object through a transaction is dependent upon the ability to lock on to the object. Based upon the access operation as well as the lock type, the acquisition of a lock might be postponed or blocked, if a separate transaction has locked the specific object. The term two-way locking signifies that two different transactions cannot lock on to the same object within the database at the same time.
This feature refers to the capability of various mechanisms in a DBMS to handle isolation and all ensure correctness of the database information subsequent to a transaction. The property is commonly utilized by Storage and Database engines to ensure the correctness of various DBMS processes as well as for ensuring proper execution of concurrent transactions. The main function of concurrency control is to ensure optimal levels of performance in the database even if various constraints are placed on the operations of the database. This specific feature of a database transaction is crucial for maintaining the accuracy of information on a database even though the serialization process may be partially compromised to improve the performance of the database.
Most enterprise database software feature standardized database transaction procedures depending on the database solution being used by the organization. In the current software development space, many an application maintenance company / Software Development Company provides their own customized database transaction solution by factoring in the requirements specified by a client or group of clients. However, such custom solutions are often cost inhibitive for SMEs, who mostly use the generic options of database transaction solutions provided with a standard database software package.