Databases

Data: can be words, numbers, pictures etc. It is important to remember that we get useful information from our raw data by processing it in different ways.

Database: a database is an ordered collection of related data that a user can process in different ways in order to extract useful information.

Computerised Databases

Using a computer to store a database has a number of advantages:/p>

  • Speed: a computer can search through a large amount of data much more quickly than a human can.
  • Accuracy: computers donít get tired, bored or accidentally skip a number of records. You can be sure that the results found in a computerís database are as accurate as they were when the data was entered in.

Main Features of a Computer Database

Databases are made up of four main parts:

  • Tables: data is stored in individual tables made up of records and fields. A relational database will link tables of related data together so that it can be stored more efficiently.
    • Records: represent all the data held on an individual item.
    • Fields: are the different categories into which the data has been organized.
    • A key field has a unique value for each record in a database table, it can be used to index the records in the database.
  • Forms: are used to allow people to enter data easily into a database. A database form might look very similar to one that someone has already filled in on paper.
  • Queries: allow a user to filter out the data that they donít want, and display only those records which contain data that they are interested in. A simple query might only search the database for data that matches one criterion. A complex query is more likely to search for records that match two or more criteria.
  • Reports: allow you to print just the data that you want. You can choose to display only those records matching a query, and only those fields that are relevant to your search. You may choose to order or group your data in different ways and add summary details to your printout. This means that the same database of personal information can be used to print out address labels, attendance registers and contact lists of names and telephone numbers grouped by residential area.

Questions

  1. Describe how a teacher could print out the names of the students in a year 9 form, if they had a database of all students in their school.
  2. What would be an appropriate key field for a school library to use in a database of its books?
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