Transaction processing systems

1. Transaction processing systems

2. Characteristics of transaction processing systems Transaction: event generating or modifying stored data in an info sys. Batch transaction processing collects transaction data as a group/batch Real-time transaction processing: immediate data processing Data Validation: used to check entry of transaction data Historical significance of transaction processing systems: UNIVAC Manual transaction systems: business systems that operate without the use of machines.

3. TPS Characteristics • They collect, store, modify and retrieve the transaction of an organisation. • Directly support business operations • Must be designed in conjunction w/ the organisation’s procedures. • Main information processes: collecting and storage.

4. 4 important characteristics • Rapid response (fast performance, rapid response time) • Reliability (low failure rate, quick and accurate recovery, backup and recovery procedures) • Inflexibility (every transaction processed in same way regardless of conditions) • Controlled processing (supports an organisation’s operations)

5. Examples of batch transaction processing • Clearance of cheques • Other forms of paper output

6. Large batch • Mainframe PC and magnetic tape • Payroll or stock info • Employee: hours worked, overtime earned • Payroll master file updated • Pay slips created (ALL employees)

7. 3 disadvantages in batch processing • Processing schedule predetermined • Errors unable to be corrected during processing • Sorting transaction data – expensive and time consuming

8. 2 concerns w/ real-time transaction processing • Concurrency: data cannot be changed by 2 users at same time • Atomicity: steps completed succesfully as a group. If any step fails, no other step should be completed.

9. Transaction processing monitor • Software (middleware) allowing running of TP programs. • Manages sequence of events • Provides interface between input devices and DBMS • Provides data security, ensuring transactions don’t get lost/corrupted.

10. Differences btween real-time and batch • Real time: each transaction is unique; transactions are stand-alone; requires master file to be available more often for updating; fewer errors – transaction data is validated and entered immediately; infrequent errors may occur – but often tolerated; not practical to shut down whole system (infrequent errors); more computer operators are required in real-time processing – operations not centralised. • Batch: each transaction part of a group; database not accesible all of the time; more errors; data is organised and stored before master file is updated – errors can occur during these steps; easier to maintain than real-time.

11. Data validation • Used to check the entry of transaction data. • Procedures ensure transactions are correct and have been accurately stored in the database. • Involves transaction initiation and field checking.

12. Historical significance and manual transaction systems • Historical significance: UNIVAC 1950’s • Manual transaction systems: business systems operating w/o use of machines.

13. Components of a transaction processing system • Users: take data and use it in another info system type • Participants: conduct info processing • People (from the environment): directly enter transactions and perform validation

14. Examples of real-time transaction processing • Reservation systems: set aside service/product for future use • Motels • Point-of-sale (POS) terminals: sells goods/services • Library loan systems: keeps track of items borrowed from library

15. System flowchart for a POS system Customer receipt MIS Inventory database UPC/quantity POS system Server UPC/quantity Purchase database UPC Price Inventory report Product Database

16. Examples of batch transaction processing • Cheque clearance: written order asking bank to pay money to a person • Bill generation: an invoice for goods/services supplied to a customer. • Credit card sales transaction: takes impression of customer’s card

17. Databases and files • Database: collection of data • Types: hierarchical, network, relational • Important features for design: good data placement, short transactions, real-time backup, high normalisation, archiving of historical data and good hardware configuration

18. File: block of data • Master file: info about business organisation • Transaction file: collection of transaction records • Report file: data formatted for presentation • Work file: temporary file in the system used during processing • Program file: instructions for processing of data

19. Data warehousing • Data warehouse: collects info from different data sources

20. Backup procedures • Backup: another copy of data • Recovery processes include backup, journal, checkpoint and recovery manager

21. 2 types of recovery • Backward recovery: back out or undo unwanted changes • Forward recovery: redo changes

22. Updating in a batch • Originally feasible: details were stored on punch cards or magnetic tape • 2 stages – collecting and processing of transaction data into file & updating master file • Sequential access: data accessed in a sequence. Time consuming. • Information technology: magnetic tape

23. Updating in real time • Direct/random access: data is accessed without accessing previous data items. Stores data based on an algorithm, which calculates data location. When index used, called indexed access. • Information technology: magnetic disk • Software – online and user-friendly • Rapid response time – few seconds or less

24. Other information processes • Collecting: generating transaction data • Analysing data: meet user’s information needs. Output from TPS is input to other systems

25. Hardware • MICR (Magnetic ink character recognition): used by banks to read account numbers on cheques • ATM (Automatic teller machine): banking terminal performing deposits and withdrawals • Barcode readers: used in retail to collect product information

26. Forms • Document used to collect data from a person • Examples include sign-on sheet for payroll. • On-screen forms: populates fields in a database • Web forms: used to purchase items over the internet

27. Management information systems • Provides information for the manager • Different types of reports include scheduled reports, forecasting reports, on-demand reports and exception reports

28. Issues related to transaction processing systems • Nature of work • Non-computer procedures • Bias • Importance of data • Control in transaction processing

29. Nature of work • Automation of jobs: the use of information technology to perform tasks once performed by people • People as participants: resulted in fewer jobs in banks. People are purchasing products by completing a web form.

30. Importance of data • Data security: involves series of safeguards to protect data • Encryption: coding data • Decryption: changing it back • Firewalls: used on networks to verify and authenticate all incoming data

31. Importance of data continued • Accuracy: extent data is free from errors. Errors caused by mistakes in gathering data, data entry, mismatch of data and person, or out-of-date information • Data validation: checks data entry. Checks for missing data, too high or too low data values, data values inconsistent with other data, data in wrong format. • Carried out using range checks, list checks, type checks and check digits

32. Data integrity • Describes reliability of data. • Involves accuracy, currency and relevance of data

33. ACID test • Atomicity: all steps involved in transaction completed successfully as a group • Consistency: transaction successfully transforms the system and database from one valid state to another • Isolation: transaction is processed concurrently with other transactions. As if only transaction executing the system • Durability: all changes transaction makes to database become permanent

34. Control in transaction processing • Starts with collecting, includes manner TPS manipulates data & way errors are corrected • Some people in management positions are willing to falsify transactions to promote careers

35. Manual transaction systems • Manual transaction systems are imperative in the retail environment because they were the conceptual basis for real-time TPS. They were used long before the rise in technology allowed for easier data collection and storage. Obviously, they have been around since trading and business took its early strides. In smaller stalls who still cannot afford the technology corporations use, it is necessary to use manual transaction systems to record business activities. Manual transaction systems are based on a clear set of rules followed by a person. They make it easier to transmit the data into a format suitable for recording onto an information technology e.g. a computer. Of course, computerisation of a manual T.S. brings benefits, when used by a large retail organisation. It increases the rate at which products are sold, which means more profit for the retail chain. The less time taken for a customer to purchase a product is invaluable in customer satisfaction, as there are lesser queues – therefore lesser time spent on waiting. Also manual T.S.s provides the retail chain with information in what products are on demand. The retail chain capitalises on this information on consumer habits and they can tailor their products to attract more customers, thereby meaning more profit.

36. Databases and files • In any large retail chain/organisation, the information processes often vary. In the handling of data, the storage and retrieval of data must be spot on. Retail chains rely on this trait for the success of their business.

37. Designing the new solution continued • Context diagrams provide an easy way to visualise information. Consulting this design tool will help in simplifying the development of the new system, as it clearly shows the flow of data in the system. • A DFD will be used to provide more detail into what the participants can do in regards to this new solution. It has greater detail than the context diagram. • Decision trees are very important in this retail context. Almost anyone can immediately identify what will transpire with this solution, what needs to be done in order to accomplish the goals, etc. it represents all possible decisions and the outcomes of those decisions. • A Data dictionary provides a comprehensive list of the data.

38. Implementing the new solution • Participant training, as outlined before, will come in handy in ensuring that our employees and workers can use the system and understand its benefits. Training manuals will be accessible. Technical support in troubleshooting problems will be gained online through an always-on internet connection. • Pilot conversion ensures that all our retail chain stores across Australia will have the latest technology available to them concurrently. This also ensures that the system can be trialled in different regions e.g. rural as opposed to urban. If successful, the new solution is guaranteed to be functioning within acceptable standards and will be implemented throughout the larger centres. • Of course, testing the new system ensures that it works. Diagnostic software and general operation are examples of testing. The reliability of the backup system is integral in the new system’s success.