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ForenameSurnameFormSubjectTeacherGrade HarrySmithAICTMiss BunceA FionaJonesBHistoryMr EvansB HarrySmithAHistoryMr EvansB JennyFieldsBArtMiss GoldA HarrySmithAArtMiss.

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Presentation on theme: "ForenameSurnameFormSubjectTeacherGrade HarrySmithAICTMiss BunceA FionaJonesBHistoryMr EvansB HarrySmithAHistoryMr EvansB JennyFieldsBArtMiss GoldA HarrySmithAArtMiss."— Presentation transcript:

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2 ForenameSurnameFormSubjectTeacherGrade HarrySmithAICTMiss BunceA FionaJonesBHistoryMr EvansB HarrySmithAHistoryMr EvansB JennyFieldsBArtMiss GoldA HarrySmithAArtMiss ColdA JennyFieldsAICTMiss BunceA What is the problem with this flat file database?

3 ForenameSurnameFormSubjectTeacherGrade HarrySmithAICTMiss BunceA FionaJonesBHistoryMr EvansB HarrySmithAHistoryMr EvansB JennyFieldsBArtMiss GoldA HarrySmithAArtMiss ColdA JennyFieldsAICTMiss BunceA 1.Data is duplicated – each exam entry requires the pupil data to be entered again 2.Data is inconsistent – mistakes are made 3.Difficult to add an extra field

4 Large collection of data items stored in separate tables with links between them e.g. – driving school has students, lessons and lesson types – all linked by the lesson table

5 You can view all the related data together

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7  Data independence – data and programs stored separately. You can add an extra table and it won’t affect the programs.  Data consistency – data is only stored once – no danger of it being updated in one place and not in another  No data redundancy – data is not duplicated unnecessarily

8  More information available to users - all information is stored centrally – not in separate departments  Ease of use – queries etc.  Data integrity – validation ensures data is as correct as possible  Greater security – authorised users – different access levels

9  Complex and costly to set up  Needs greater knowledge to set up  Users require more training  If data used for a range of applications – security and confidentiality issues arise

10 Database is made of records – each record has a structure containing fields.

11 Data typeDescriptionExample IntegerWhole number4 or 5 or CurrencyNumber representing a financial amount £4.55 or $0.99 StringText or charactersJosh or 41 Bridge Street Date/timeDates or times in any format 15 th May 2010 or 14:56 or 09/12/2009 BooleanData which can only be one of two states Yes or no True or false

12  Query – a method of searching a database for specific information  Report – printed output from a database for a specific purpose  Form – an interface to a table or group of linked tables for data entry  Import – data from an external data source brought into the database  Export – data from the database used for another purpose – e.g. Mail merge letter

13  Fields can be coded – e.g. M or F  Database can have validation  Each record has a key field which is a unique identifier


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