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TPS Characteristics

The HCS TPS Topic

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TPS Characteristics

  1. 1. IPT Y12 Option Topic Transaction Processing Systems
  2. 2. Saturday, 26 September 2009 Characteristics of TPS Transaction processing systems are crucial to the operation of most finance, banking and electronic commerce organisations. Transaction processing is primarily concerned with maintaining data integrity. Such systems can operate at the single database level, but they also operate at higher levels where data in many databases and even many different systems is involved. For example transferring funds from one financial institution to another. So what is a transaction? A transaction is a series of events that when performed together complete some unit of work that is important to an organisation. Each transaction has two possible outcomes, either it is a complete success or it is a complete failure .
  3. 3. Saturday, 26 September 2009 Characteristics of TPS A Transaction Processing System (TPS) is a type of information system that collects, stores, modifies and retrieves the data transactions of an enterprise or large business. <ul><li>the need to handle hundreds, even thousands of simultaneous Users </li></ul><ul><li>the need to allow many Users to work on the same set of data, with immediate updating </li></ul><ul><li>the need to handle errors in a safe and consistent manner </li></ul>
  4. 4. <ul><li>Characteristics </li></ul><ul><li>TPS collect, store, modify and retrieve transactions. </li></ul><ul><li>It is also a unit of work composed of multiple operations that must all succeed or must all fail (Atomicity) </li></ul><ul><li>Each operation generates and/or modifies data. </li></ul><ul><li>Must pass the ACID test. </li></ul><ul><li>Examples: </li></ul><ul><ul><li>POS </li></ul></ul><ul><ul><li>Processing credit cards </li></ul></ul><ul><ul><li>Motel/Hotel reservations </li></ul></ul><ul><li>The main Information Processes are collecting and storing. </li></ul>T ransaction P rocessing S ystems Saturday, 26 September 2009 Characteristics of TPS
  5. 5. The ACID properties of TPS <ul><li>Transactions are known as atomic , meaning that the </li></ul><ul><li>transaction will either happen or not. If one account is </li></ul><ul><li>debited, then another account has to be credited. </li></ul><ul><li>Atomicity :- all transactions/operations must succeed or fail as a group. </li></ul><ul><li>Consistency :- all parties must agree on the facts of the exchange </li></ul><ul><li>Isolation :- transactions must be independent of each other. </li></ul><ul><li>Durability :- the effects of a completed transaction should be lasting </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  6. 6. The ACID properties of TPS <ul><li>ACID is an acronym for atomicity, consistency, isolation and durability. The aim is to ensure all transactions comply with these four properties. They ensure that: </li></ul><ul><li>transactions are never incomplete (atomicity), the data is never inconsistent. </li></ul><ul><li>(consistency), transactions do not intrude or affect each other (isolation) and that the </li></ul><ul><li>results of a completed transaction are permanent (durability). </li></ul><ul><li>All these properties combine to ensure the integrity of all data is maintained before, during and after each transaction. </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  7. 7. <ul><li>Rapid processing/response - customers cannot wait for a TPS to respond. Speed from input to output must be in a few seconds. </li></ul><ul><li>Reliability - Breakdown will disrupt or stop business. Failure rate must be low. Quick and accurate recovery. Backup and recovery procedures are essential. </li></ul><ul><li>Inflexibility - Every transaction to be processed in the same way. Operation must be standardized. Transactions must be processed in the same way each time to maximise efficiency. To ensure this, TPS interfaces are designed to acquire identical data for each transaction, regardless of the customer. </li></ul><ul><li>Controlled processing - must support the business operations. A TPS should enforce and maintain roles and responsibilities of an organisation. </li></ul>Saturday, 26 September 2009 Characteristics of TPS CHARACTERISTICS OF TPS
  8. 8. Advantages of a computer-based transaction over a manual system. Manual transaction systems are business systems that operate without the use of machines <ul><li>Larger numbers of transactions can be processed in a shorter amount of time: cheque processing. </li></ul><ul><li>Greater reliability. –Less prone to human error –data is much more reliable </li></ul><ul><li>Increased storage capacity and greater ease of retrieval of stored data. More efficient in terms of space and much more reliable. Paper records deteriorate over time digital data does not. </li></ul><ul><li>Retrieval and sorting of data is more efficient than manual methods </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  9. 9. Transaction processing is easily computerised as it is based on clear set of rules <ul><li>A manual POS system has 11 operational steps </li></ul><ul><li>Examine the product and determine the price. </li></ul><ul><li>Record the product price on sale slip and add it to the total price of product. </li></ul><ul><li>Repeat steps 1 and 2 for subsequent products. </li></ul><ul><li>Check the total price of all products. </li></ul><ul><li>Informs customer of total price and wait for payment. </li></ul><ul><li>Receive payment. </li></ul><ul><li>Calculate the change owing to customer. </li></ul><ul><li>Give customer: products, copy of sales slip and change. </li></ul><ul><li>Repeat steps 1 to 8 for next customer. </li></ul><ul><li>At the end of day: add total sales slips = money collected </li></ul><ul><li>Do a stocktake to count all products remaining. </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  10. 10. Real- time processing <ul><li>Transactions are handled individually . </li></ul><ul><li>Processing and output is instant . </li></ul><ul><li>Does not require access to an online database. </li></ul><ul><li>Involves using a network to link terminal to mainframe. </li></ul><ul><li>Involves a large number of users. </li></ul><ul><li>E.g Airline reservation, banking transaction systems, library system, student enrolment systems </li></ul><ul><li>System failure is critical- processing cannot take place. </li></ul><ul><li>Difficult to maintain than batch processing </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  11. 11. Batch processing <ul><li>Transactions are handled as a group/batch and processes it later. </li></ul><ul><li>Processing and output is delayed </li></ul><ul><li>Processing occurs at a convenient time: during evening when PCs are idle and networks are not busy </li></ul><ul><li>Processing cost are lower per transaction </li></ul><ul><li>Processing occurs without human interaction </li></ul><ul><li>Occupy much of the network capacity. </li></ul><ul><li>Data errors will stop a batch process </li></ul><ul><li>E.g. Payroll, cheques, billing for electricity, E-way and telephone. </li></ul><ul><li>The only feasible form of processing when data was stored on punch cards or tapes. </li></ul><ul><li>System failure is less critical-time to restore system </li></ul><ul><li>Database not always available. </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  12. 12. Two main concerns with real-time processing <ul><li>Concurrency </li></ul><ul><li>Two user cannot change the same data at the same time. </li></ul><ul><li>One user cannot change a piece of data before another user has finished with it. </li></ul><ul><li>Atomicity </li></ul><ul><li>Ensures that all of the steps involved in a transaction are completed successfully as a group </li></ul><ul><li>If any steps fails, no other step should be completed. </li></ul><ul><li>In order for transaction processing to work, all the operations must succeed or fail as a group. </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  13. 13. Real-time transaction processing Saturday, 26 September 2009 Characteristics of TPS Terminal Terminal Terminal User Interface TP Monitor Application DBMS Database A Transaction processing monitor (TP monitor) is software that allows the transaction processing application programs to run efficiently. <ul><li>It manages the sequence of events that are part of a transaction </li></ul><ul><li>It provides a standard interface between the input devices(terminals), the TP application programs, and the DBMS </li></ul><ul><li>It also provides data security </li></ul><ul><li>It is used in conjunction with a operating system. </li></ul>
  14. 14. Differences between real-time and batch processing <ul><li>Each transaction in real-time is unique . Transaction are stand-alone both in the entry to the system and also in the handling of output. </li></ul><ul><li>Real-time processing requires the master file to be available more often than batch processing </li></ul><ul><li>The DB is not accessible all of the time for batch processing. </li></ul><ul><li>Real-time processing has fewer errors than batch processing : data is validated and entered immediately. With batch , data is organised and stored before the master file is updated. Errors can stop processing </li></ul><ul><li>Infrequent errors may occur in real-time processing . Errors are tolerated. </li></ul><ul><li>More operators required in real-time processing -operators are not centralised. </li></ul><ul><li>Difficult to maintain real-time system than batch processing system. </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  15. 15. Credit Card Machines Saturday, 26 September 2009 Characteristics of TPS Real-time processing Batch processing EFTPOS Manual impression
  16. 16. Data validation <ul><li>Data validation is used to check the entry of transaction data. It involves transaction initiation and field checking. </li></ul><ul><li>Transaction initiation is used to acknowledge that the TP monitor is ready to receive the transaction data. It is used in real-time processing to eliminate errors. (ATM or Online shopping) </li></ul><ul><li>Field checking occurs when the transaction data is entered into the database: (files, records, fields and characters). Data validation is carried out by checking the fields, using a range check, list check, type check or check digit. </li></ul><ul><li>Data validation in real - time systems allows corrections to be made as the data is entered. </li></ul><ul><li>It is impossible to validate all data in a TPS </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  17. 17. Historical significance of TPS <ul><li>Transaction processing was the first type of information system. </li></ul><ul><li>Much of modern data processing is still based on traditional pre- computing methods </li></ul><ul><li>Clerk manual systems include: </li></ul><ul><ul><li>Gathering data on paper application forms </li></ul></ul><ul><ul><li>Transferring the data to their own system for storage. </li></ul></ul><ul><ul><li>Storing data in records in sequence. </li></ul></ul><ul><ul><li>Transcribing information to invoices, orders and accounts. </li></ul></ul><ul><ul><li>Updating records with addition, deletions and editing. </li></ul></ul><ul><li>The first commercially available electronic computer was called UNIVAC (Universal Automatic Computer) </li></ul>Saturday, 26 September 2009 Characteristics of TPS
  18. 18. The end of characteristics of TPS <ul><li>Outcomes </li></ul><ul><li>After studying this unit, you should be able to: </li></ul><ul><ul><li>Describe the historical importance of transaction processing. </li></ul></ul><ul><ul><li>Identify types of transaction processing. </li></ul></ul><ul><ul><li>Investigate data validation . </li></ul></ul>Saturday, 26 September 2009 Characteristics of TPS