Information handling/ databases

Information handling/ databases

1. The uses of databases

   • Store data easily and take up less space
   • Organise data
   • Easily update data
   • Sorting data

2. Searching for data

   • creating queries
     • written in the form of a field operator
     • Simple queries
     • Complex queries
       • combine 2 or more simple searches together
     • querie operators

3. Data types

4. Database structure (fields, records and files)

   • Key fields (unique ID)
     • Key fields are unique and cannot be the same as something

5. Why use a database?

   • Many people use databases instead of paper-based databases because they are quicker and easy to use
   • People use databases when they own or work for a company to easily store or find data.
   • Can hold a vast ammount of data instead of a limited ammount if you were using paper.
   • Very fast to find a spesific record
     • Could take alot longer if you were trying to search for a paper-based record.
   • You can easily update or amend records. e.g. New surname or address
     • If using paper-based records they have to be changed manually and may look messy if crossed out.
   • Easy to make a back-up incase of data loss.
     • Paper based databases would be hard to back up because ever sheet would have to be re-written.
   • Data can be searched easily, eg 'find all Ford cars'.
     • It is hard to find data in a paper-based database because you have to find a certain piece of paper and cannot easily search it in any way
   • More than one person can access the same database at the same time - multi-access.
     • When using a paper-based database only one person can use it at one time because it can only be in one place at once.

6. validation-ensure sensible data is entered.

   • Lists
     • A drop down list to limit someones answers
     • Drop down lists
   • Range check
     • Limit the amount of of numbers used
     • Upper limit
       • sets a limit. e.g. the max price of a item in the store is £100.
     • Lower limit
       • stops people entering a lower number. e.g.
   • Type check
     • A type check will ensure that a correct type of data is entered into the field.
   • Length check
     • Somtimes you have a set of data which always has the same ammount of characters such as a phone number which has 11 numbers.
   • Format check
     • Format checks are used to check that the correct combination of letters and numbers are used.

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