What is transaction processing?
Transaction processing is a computer-based group of logical operations. In order for transaction processing to work, all the operations must succeed or fail as a group. A simple example of transaction processing is paying a utility bill from your bank account. The process of paying a bill from your account consists of debiting your account by say, 100 US dollars (USD), and crediting your utility provider’s account. This may seem like a simple transaction, but it may actually consist of several sub-operations. If the debit of 100 USD was successful, but the credit did not go through to the utility provider’s account, then the transaction would fail. Your 100 USD would be lost somewhere in the transaction. The transaction processing system allows all the operations to be grouped into a single transaction in order to prevent problems in consistency. Systems capable of transaction processing must pass tests for atomicity, consistency, isolation and durability, otherwise known as the ACID t
In Chapter 1, you were introduced to the concepts behind transaction processing. But you may still be wondering just what this is. Transaction processing has been around since the mainframe days of computing. You may have heard of, or have even used, products such as CICS, Tuxedo, or TopEnd. These are all examples of transaction processing systems, which provide transaction services to applications that use them. There are a number of attributes that make up transaction processing. In order to discuss transaction processing, we must first agree on a definition of what a transaction is. A transaction is an atomic unit of work that either fails or succeeds. There is no such thing as a partial completion of a transaction. Since a transaction can be made up of many steps, each step in the transaction must succeed for the transaction to be successful. If any one part of the transaction fails, then the entire transaction fails. When a transaction fails, the system needs to return to the stat
