TPS - Transaction Processing

Characteristics of transaction processing systems

1. Batch transaction processing
2. Real-time transaction processing
3. Data validation
4. Historical significance of transaction processing systems
5. Manual transaction systems
6. Transaction: event generating or modifying stored data in an info sys.
7. Batch transaction processing collects transaction data as a group/batch and processed later (time delay)
8. Real-time transaction processing: immediate data processing
9. Data Validation: used to check entry of transaction data
10. Historical significance of transaction processing systems: UNIVAC
11. Manual transaction systems: business systems that operate without the use of machines. 

TPS Characteristics:

1. They collect, store, modify and retrieve the transaction of an organisation.
2. Directly support business operations
3. Must be designed in conjunction w/ the organisation’s procedures.
4. Main information processes: collecting and storage.
5. Rapid response (fast performance, rapid response time)
6. Reliability (low failure rate, quick and accurate recovery, backup and recovery procedures)
7. Inflexibility (every transaction processed in same way regardless of conditions)
8. Controlled processing (supports an organisation’s operations)

Batch Processing - Examples:

1. Clearance of cheques
2. Other forms of paper output

Disadvantages in batch processing

1. Processing schedule predetermined
2. Errors unable to be corrected during processing
3. Sorting transaction data – expensive and time consuming

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

Differences btween real-time and batch

1. 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.
2. 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.

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

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

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

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

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

Data warehousing
Data warehouse: collects info from different data sources
Consolidated, subject-oriented, historical and read-only

Forms

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

Decision support systems

1. Assist people to make decisions by providing information, models and analysis tools
2. Data mining: used in DSSs to find relationships and patterns in the data

Management information systems - MIS

1. Provides information for the manager
2. Different types of reports include scheduled reports, forecasting reports, on-demand reports and exception reports

Key issues in designing an MIS or DSS

1. How a system will be modeled
2. How model of system will be handled by the computer
3. What data will be used
4. How far into the future trends will be extrapolated

Issues related to transaction processing systems

1. Nature of work
2. Non-computer procedures
3. Bias
4. Importance of data
5. Control in transaction processing

Nature of work

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

Non-computer procedures

1. Organisations rely on TPS
2. Manual backup procedure if system crashes
3. When system up & running, user needs procedure to enter manual transactions

Bias

1. Data gathered can be presented in biased way using tables and charts
2. Becomes ethical issue when relevant information is misrepresented

Importance of data

1. Data security: involves series of safeguards to protect data
2. Encryption: coding data
3. Decryption: changing it back
4. Firewalls: used on networks to verify and authenticate all incoming data
5. 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
6. 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. 
7. Carried out using range checks, list checks, type checks and check digits

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

ACID test

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

Control in transaction processing
Starts with collecting, includes manner TPS manipulates data & way errors are corrected

Aspects of TPS relevant to - large retail company

1. Real-time transaction processing
2. Manual transaction systems
3. Components of a TPS
4. Credit card sales transactions
5. Database and files
6. Updating in a batch, real-time
7. Other information processes: collecting
8. Nature of work
9. Non-computer procedures
10. Bias