Transaction Processing Systems

Defining a TPS A TPS collects, stores, modifies and retrieves the transactions of an organisation

Characteristics of a TPS Rapid response – fast performance with rapid results Reliability – well designed backup and recovery with a low failure rate Inflexibility – treat every transaction equally Controlled processing – maintain specific requirements for the roles and responsibilities of different employees.

Batch Processing in a TPS Batch transaction processing collects the transaction data as a group (batch) and processes it at a later time eg cheque clearance or generating pay cheques.

Real-Time Processing in a TPS Real-time transaction processing is the immediate processing of data eg-airline reservation systems or banking transaction systems

Transaction processing monitor A TP monitor is software that provides a standard interface between the input devices, the transaction processing application programs and the DBMS. It also provides data security and is an important part of real-time processing.

Real-Time vs. Batch Real-time: Each transaction is unique Cheaper Transactions must have similar inputs and outputs Any error is not immediately detected Easier to maintain Less IT required Real-time: Each transaction is unique Requires master file to be readily available Has fewer errors as data is entered and validated immediately More computer operators required

Data validation Involves procedures to ensure that transactions are correct and have been accurately stored in the database Although essential, it is impossible to validate all the data as some errors are very difficult to detect eg typing ‘1986’ instead of ‘1987’

Manual transactions Manual transaction systems are business systems which operate without an information system (i.e. no computers). They have been around for thousands of years. The earliest writings are Sumerian business receipts on clay tablets which are around 5 thousand years old. But of course people still keep manual transaction records.

Manual transactions You probably keep receipts for goods that you buy. You may keep these for tax reasons or for warranties but either way they are transaction records Until recent times many records were still stored in account books. This required bookkeepers to balance the accounts -These are the manual equivalent of spreadsheets

Manual Transactions Transferring paper based records into an electronic system has many benefits including: customers can purchase goods at their convenience it is easy to do stock takes reduced wage costs Whatever the peripheral benefits computerization of a manual system will aim to maximize profits.

Manual Transaction Systems A manual transaction system is a business system that operates without the use of machines People record the data and perform stock takes to check for misplaced/stolen money or stock Computerisation provides significant benefits as it is faster, more affective and provides relevant information for the business.

Components of a TPS Users – a main feature of a TPS, they often take the data provided by it and use it in another information system Participants - people who conduct the information processing, success or failure is dependant on them People from the environment become participants when they directly enter transactions and perform validation eg withdrawing money from an ATM

Examples of TPSs Real-Time Batch Reservation systems POS terminals Library loan systems Batch Cheque clearance Bill generation Credit card sales and transactions

Storing and Retrieving – Databases A database is an organised collection of data. There are three structures: Hierarchical Network Relational

Important Database Features Real-time TPS databases should have: Good data placement Short transactions Real-time backup High normalisation Archiving of historical data Good hardware configuration

File Types in a TPS Master file Transaction file Report file Work file Program file

Data Warehousing A data warehouse is a database that collects information from different data sources. Data has to be: Consolidated Subject-oriented Historical Read-only

Backup and Recovery A backup is another copy of data that could be used to rebuild the system, if failure occur Recovery of a database involves: The backup Journal Checkpoint Recovery manager

Grandfather-Father-Son A backup procedure that refers to at least three generations of backup master files Commonly used with magnetic tape If the TPS fails, the first generation backup is used (son) to recover it, if this is also corrupted the next generation is used (father) and so on

Updating data In a batch: Real-time Involves sequential access Most common medium is magnetic tape Real-time Involves direct access Can be stored on magnetic disk, CD, hard disk and others

Collecting data in a TPS Hardware MICR (magnetic ink character recognition) ATM Barcode readers Forms On-screen forms Web forms

Analysing data from a TPS Done as input in other information systems including: DSSs, decision support systems MISs, management information systems

Issues Related to TPSs Nature of work is changing Bias free data Automation of jobs People as participants Bias free data Data security Data accuracy Data integrity (the ACID test)

The ACID Test Atomicity – all steps involved in a transaction are completed as a group Consistency – database is successfully transformed from one state to another Isolation – simultaneous transactions don’t interfere with each other’s database updates Durability – all changes to the database are permanent when the transaction is committed.

Collecting data Bar-code readers EFT- POS devices Cash registers Web forms

Organising DBMS – sort and organise all the data from the transactions from the internet, different terminals and stores

Analysing DSS – using data mining to determine relationships and patterns in product sales at stores MIS – assist managers in generating stock inventories, payrolls, orders and budgets.

Storing and Retrieving Data should be stored on-site with backups both on-site at each store as well as off-site at the head office mainframe computer Hard disks, floppy disks, CDs and/or other storage media should be used

Processing Backups should be done using the grandfather-father-son method updated at least two times per day Transaction journals should be kept for web sales as well as each terminal for system recovery and to track down any missing or stolen money.

Transmitting and Receiving Each terminal at each store should be connected to the mainframe in that store in a LAN Each mainframe at each store should be connected to the mainframe at the head office as well as the internet for web transactions in a secure WAN

Displaying Each terminal needs a printing device for customer receipts A user-friendly web interface for internet transactions

Implementation A new system can be implemented in several different ways: Direct conversion Phased conversion Parallel conversion Pilot conversion Old New New Old Old Old Old New New Old New New

Social and Ethical Issues Every customer has a right to their own privacy and details stored such as credit card number, name and address have to be secure The implementation of a new TPS would require staff to be skilled in different areas Transaction data has to be secure during transmission to the mainframe as well as while stored

Transaction Processing system QUIZ

1. Which of these is not an important characteristic of a TPS Reliability Rapid response Flexibility Controlled processing

2. Real-time processing is: Cheaper than batch Faster than batch Not real at all Used in bill generation

3. Which of the following is not a component of a TPS: Users Participants People from environment Data mining

4. Which is not an example of a TPS: POS terminal Airline reservation system Library loan system E-mail

5. In a manual transaction system: People record the data and perform stock takes Robotic arms perform manual labour People operate computers and machinery There is no data

6. The five basic file types in a TPS are: Master file, slave file, teacher file, child file and print file Terminal file, processing file, master file, slave file and backup file JPEG, GIF, PGF, PNG and PSD Master file, transaction file, report file, work file and program file

7. The ACID test involves: The Atomic Composition of Information Databases Testing the chemical properties of storage media in TPSs against sulphuric acid The Atomicity, Concurrency, Isolation and Dataframe The Atomicity, Consistency, Isolation and Durability

9. Recovery of a database involves: The backup, journal, TP monitor and operating system The backup, journal, checkpoint and recovery manager Travelling back in time to a point where the database was functional The storage of backups off-site ANSWER

10. Which of these is not a database structure: Relational Hierarchical Architectural Network