The Teradata system comprises of several interconnected software and hardware which intercommunicate within each other to bring out the best of Teradata as a whole. Following are the main components in the Teradata system.

• Call Level Interface (CLI)
• Data Communications Manager or Teradata Director Program (TDP)
• Parser and Dispatcher or Parsing Engine (PE)
• Interprocessor Network (BYNET)
• Database Manager or Access Module Processor (AMP)
• File System
• Disk Subsystem

The principle objective of a transaction is to facilitate data completeness when a sequence of events happens. Although it is not necessary that a “sequence of events” has to take place. A single event can also be considered as a transaction. A single event could be any data manipulation events like INSERTING, UPDATING or DELETING a row or set of rows.

Transaction is a logical unit of work. When we say a logical unit, it means the unit of work has a logic involved in it and this unit of work has to be performed in its completeness or not at all. A transaction cannot be completed partially.

For example, let’s say in an organization there is a change in the employee’s salary. This revised salary has to be applied to all the employees or none of the employees. Similarly when a bank pays interest on Savings Account, it has to pay interest on all the Savings Account that is present in the books or NONE.