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1 AQA ICT AS Level © Nelson Thornes 2008 1 Types of data.

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Presentation on theme: "1 AQA ICT AS Level © Nelson Thornes 2008 1 Types of data."— Presentation transcript:

1 1 AQA ICT AS Level © Nelson Thornes 2008 1 Types of data

2 2 AQA ICT AS Level © Nelson Thornes 2008 2 Data types Is data always words or numbers? No. Here are the data types available in Access. Click on one or more hyperlinks to find out more. TextText, Memo, Number, Date/Time, Currency, AutoNumber, Yes/No, OLE Object, Hyperlink, Lookup WizardMemoNumber Date/TimeCurrency AutoNumberYes/No OLE ObjectHyperlink Lookup Wizard Click here when you have finished investigating data types.here

3 3 AQA ICT AS Level © Nelson Thornes 2008 3 In a database, what field names would expect data type text?  Surname  Address line 1  Mode of transport  Telephone number* *Click here for more information on telephone numbers or here to continue.here Text

4 4 AQA ICT AS Level © Nelson Thornes 2008 4 Why is 01225 843878 treated as text? Although the data is made up of numbers this is really a code. Telephone numbers used to contain letters as well. Databases can include calculated fields but calculations cannot be formed with telephone numbers. Click here to continue with the presentation.here Telephone number

5 5 AQA ICT AS Level © Nelson Thornes 2008 5 Memo fields enable you to enter continuous, free response text. You do not have to specify the field length as you would with a text field. The maximum length is 65,535 characters. Click here to continue.here Memo

6 6 AQA ICT AS Level © Nelson Thornes 2008 6 Number This one is very straightforward. It is used to store numerical data. Remember that Access can use these fields to carry out calculations – a calculated field. Click here to continue.here

7 7 AQA ICT AS Level © Nelson Thornes 2008 7 You can set these fields to store a date or time or both. The Input Mask lets you choose how you want it displayed. Click here to continue.here Date and Time

8 8 AQA ICT AS Level © Nelson Thornes 2008 8 Currency fields are the same as numbers but set to 2 decimal places. They also display the currency symbol, for example £, €. Click here to continue.here Currency

9 9 AQA ICT AS Level © Nelson Thornes 2008 9 This field will automatically number your records. It will not allow duplicates so you could use this field as the key field. Click here to continue.here Auto number

10 10 AQA ICT AS Level © Nelson Thornes 2008 10 AQA ICT AS Level © Nelson Thornes 2008 A logical field expects the data to be Yes or No, or True or False. Data entry is done by ticking the box using the mouse. James and Maureen have passed, David has not. Click here to continue.here Yes/No

11 11 AQA ICT AS Level © Nelson Thornes 2008 11 AQA ICT AS Level © Nelson Thornes 2008 This data type enables you to include pictures or sounds in your database. Click here to continue.here OLE Object

12 12 AQA ICT AS Level © Nelson Thornes 2008 12 AQA ICT AS Level © Nelson Thornes 2008 This will put a hyperlink on your reports, perhaps the subject’s email address or a webpage. You may have e-mail address as a field but this will enable you to access it. Click here to continue.here Hyperlink

13 13 AQA ICT AS Level © Nelson Thornes 2008 13 AQA ICT AS Level © Nelson Thornes 2008 A lookup simplifies data entry as you can select from a drop down box. Here, you select the name of the GP without having to type it in. Click here to continue.here Lookup

14 14 AQA ICT AS Level © Nelson Thornes 2008 14 AQA ICT AS Level © Nelson Thornes 2008 Data on its own has no meaning. 16,31,17,04,20,39 is just a series of numbers. Once processed it becomes information, for example, the data is a string of candidate numbers and marks. The candidate numbers can be looked up to find candidate name. The marks can be looked up in a table of grade boundaries. So the information would be: Robinson, B C Grade Leighton, M U Grade Ahmed, MB Grade Data is input to a computer system and, after processing, becomes information. Summary


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