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Information Systems & Databases 2.1) Information Systems
• Information systems are created to provide access to information for an organisation or individual.• They perform a set of information processes involving participants, data/information and information technology.• In a large number of information systems, the data is held in a database and accessed through a database management system (DBMS).
• The characteristics of an information system are: • organisation of data into information – careful thought is required to sort and link large amounts of data (e.g. data dictionary) • analysis of data to give knowledge – analysed data should be output into useful forms, such as tables, charts, queries and forms.
• There are many different types of information systems, including: • transaction processing systems • decision support systems • expert systems • management information systems • office automation systems• Transaction processing systems (TPS’s) deal with the daily transactions of an organisation.
• This could include buying and selling of goods and services, banking, shares and point-of-sale (POS) transactions.• Organisations rely heavily upon their TPS, a breakdown will disrupt operations, so they must be well designed with solid backup and recovery procedures.• TPS’s use both real-time and batch processing, depending upon their circumstances.
• Decision support systems (DSS’s) assist people by providing information, models and analysis tools.• E.g. stockmarket analysis software• A DSS creates a mathematical model utilising the variables of the situation and then uses various tools to answer ‘what-if’ questions.• These tools could include statistical tools, databases, spreadsheets and graphics.
• The reliability of the DSS depends upon the accuracy of the model and the manager’s ability to formulate good questions.• An expert system is a special kind of DSS.• They are used to provide information and solve problems that would otherwise require a person experienced in that field.
• They are useful in diagnosing, monitoring, selecting, designing, predicting and training.• An expert system asks a series of questions and compares the answers to a knowledge base.• A knowledge base is a set of facts and ‘if-then’ rules supplied by an expert or team of experts.• E.g. online medical diagnosis.
• The answers provided by an expert system are sometimes incorrect, since the logic of the knowledge base is not always followed.• Management information systems (MIS’s) provide information for the organisation’s managers.• An MIS provides an overview as to how the organisation is faring.• E.g. reports on sales, inventory, payroll, orders and budgets.
• Office automation systems provide a means to completing routine administrative tasks.• They use a range of tools including word processing, databases, spreadsheets, desktop publishing (DTP), presentation programs and project management software.• They also utilise communications technology such as web browsers, email, instant messaging and telepresence systems.
• Regularly published newsletters and memos are both examples of this kind of system in action.• Another suitable example is quickly producing large numbers of letters and documents through a mail-merge process.• Most of these different kinds of information systems use a database.• Databases are accessed through a software package known as a database management system (DBMS).
• A DBMS has no data in it, but rather accesses and manipulates the data found within a database file.• A database is an organised collection of data that can be sorted and searched for information. [Read MovieTime case study (p.39) and then answer Exercise Q.9]