Post on 29-Nov-2014
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Information Systems & Information Systems & DatabasesDatabases
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]