Information Systems & Databases

 Information systems have existed for as long as writing has existed. For the majority of our history, manual methods have been used for organising and processing information.  Manual methods are still in common use today: Telephone booksAddress booksDiary Appointment booksRecipe books  Computer versions of these examples exist but many people still prefer the manual versions to the electronic ones

 Standard system tools can be used to describe any information system – manual or electronic.  In the case of a data flow diagram, the storage symbol can represent any storage device, even an appointment book. Check diary Update diary Request result Diary Appointment request

Manual systems offer some advantages over electronic systems, specifically:  They do not require a computer, power supply or batteries  They can be highly portable, weigh very little and fit inside a briefcase or bag, notable exceptions include telephone books and encyclopaedia sets  No special skills or training are needed to use them Their disadvantages include:  A very inflexible layout  Access is usually only by one method – for example, alphabetical by surname or chronological by date  Usually only one person can access the database at a time

To overcome the limitations, manual information systems are frequently forced to set up additional copies of data. For example:  A manual catologue system for a library would have several sets of catalogue cards:  One set organised by author surnames  A second set organised by book titles  a third set organised by subject  Managing a system like this means extra work to maintain all data sets  Manual informatio nsystems are usually slow when you are trying to locate a particular data item.  Information in a card-based system could easily become impossible to find if cards were lost or filed in the wrong place.

Computer-based information systems offer many advantages over the manual versions:  They are considerably faster  The data do not have to be in a set order  Data management is much easier  The data can be easily exchanged between applications and over networks However there are also disadvantages:  The data can only be accessed if you have a computer  Training is usually required  The exchange of data with other computers creates problems of security and confidentiality

 Almost any software package can store and manage data  Word processors and spreadsheet programs can be used to store and manage simple lists like names and addresses. Software such as Outlook is specifically designed to manage items such as calendars, appointment diaries, ‘to do’ lists and contacts as well as handling . Software specifically designed to organise data and produce information falls into three broad categories:  Flat file database management systems  Relational database management systems  Hypermedia systems

Flat file database management systems (DBMS) allow you to use and manage only one database at a time.  Microsft Works (database) and Outlook are flat file DBMS.  Microsoft Excel has the ability to manage data as a flat file DBMS  Flat file databases are ideal for the majority of personal data management tasks (address books, electronic diaries) and many business tasks.  Flat file database management systems are relatively easy to learn and use.

 A relational DBMS allows you to simultaneously manage and use several separate databases.  They are called relational because it allows you to build relationships between the data in the different databases.  Microsoft Access, FoxPro, Filemaker Pro, Oracle and SAP are relational database management systems.  These systems are much harder to learn and use but are better at managing complex data processing tasks.

 Hypermedia (and hypertext) has become a popular method for accessing and displaying information over networks such as the Internet.  Sales catalogues, news, movie reviews are some common information applications using hypermedia.  Hypermedia systems are very easy to use and if used on the Web, will operate on almost any computer system.  Hypermedia-based data organising systems are not as simple to create as flat file database systems and generally have limited data processing capabilities.

Information TaskManual SystemFlat File DBMSRelational DBMSHypermedia Appointments diaryIdeal for personal use because of high portability and accessibility Ideal for business use (tracking more than one person) because of easy maintenance Too complex for the task Ideal for travelers who have access to the Web Store sales or product catalogue Ideal for letterbox drops, handouts etc Ideal for simple lists only Suitable but generally too complex for the task Ideal for access via the Web and e-commerce Stock / inventoryToo slow and difficult to maintain Ideal for simple lists only Ideal for larger and more complex lists Generally not suitable for the task Personnel recordsToo slow and difficult to maintain Ideal for simple lists only Ideal for larger and more complex lists Generally not suitable for the task, poor security and privacy Phone & address listsIdeal for personal use because of high portability and accessibility Ideal for larger lists and business use because of easy maintenance Suitable but generally too complex for the task Ideal for access via the Web Class marks & test results Ideal for portability and instant access, has good privacy and security Ideal for data processing (eg. Calculate end of year results) and to send data to other applications (eg, report writers) Too complex for the task Generally not suitable but used for the fast distribution of results (HSC) with access security Mail mergingNot suitable for the taskIdeal for the taskSuitable but generally too complex for the task Generally not suitable for the task

 In general, if you need instant access to data in any situation then manual methods will often be more efficient. However, manual methods are generally limited to simpler tasks involving smaller quantities of data.  If you need to perform complex processing tasks, have larger quantities of data or the data is quickly changing then computer- based methods will be more efficient.  Choosing between the three methods will be a matter of deciding if:  The data has to be widely distributed but little or no processing will be needed (hypermedia)  There are relationships involving data from more than one database (relational DBMS)  Basic processing operations are needed on a simple to learn and use system (flat file DBMS)

 A growing trend in information systems is the use of web-based applications for personal computers.  Instead of users purchasing and installing IMS (information management software) on their own computer or network, they access a web-based ISP such as Yahoo or Hotmail.  The applications software they need is provided as a series of personalised web pages.  A web-based appointments diary can be accessed and updated by travelling executives as well as their office staff.  Web-based systems allow you to keep in contact from anywhere in the world

 Google Calendar and Yahoo Calendar provide access to a web calendar, diary, ‘to do’ list along with personalised applications such as address books, banking, investments and news services.  Word processing, spreadsheets and other small office and home software applications.  Web-based information applications allow people to access their personal information, communications and other applications from anywhere and on any computer system – the only thing needed is a browser!  The advantages and convenience of accessing personal information services from anywhere in the world often outweigh the privacy and security issues raised by web-based systems.

REMEMBER 1. What are the two types of database information systems in common use? 2. List some of the advantages of a manual information system. 3. What is a DBMS? THINK 4. Consider the data flow diagram for a manual appointment diary. Would the diagram be different for a computerised appointment diary? Explain. 5. Complete a table for the following information tasks – a set of recipes, an adventure novel, your personal CD collection. 6. What are the privacy and security issues raised by web-based personal information systems? INVESTIGATE 7. What manual information systems are still used in you school? How could they be converted to computer based?