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ICT

Databases and data capture

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A database is a way of storing information [information: data with context or meaning ] in an organised, logical way. It's important to know when to use a database and be aware of its advantages.

Record structure

Before setting up a database [database: a structured collection of records or data stored in a computer system ], the record structure must be decided to make best use of the memory [memory: used to store data ] and backing store [backing store: a computer's primary data store, ie the hard disk ], and to make searching and report creation easier.

For example, a car showroom wants to record details of the cars it sells. Before setting up the database, the following questions need to be answered:

  1. What information is needed?
  2. What validation [validation: checking data against a set of specified rules ] could there be?

With these questions answered, informed decisions can be made about the record structure. This is how it might begin:

Record structure

Field nameField typeFormat
Registration numberAlphanumericUp to 7 characters - the key field [key field: a unique identifier for a database record or table entry ]
MakeAlphanumericUp to 15 characters
ModelAlphanumericUp to 15 characters
Date first registeredDateDDMMYY
PriceCurrencyUp to 5 numbers
TaxedYes/No (Boolean)1 character Y/N
...

When designing a database it is important to choose the correct field type. This ensures that the data [data: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information ] stored is usable and it makes validation easier. For example, if the price paid for goods was stored in a text field, then the database wouldn’t be able to add each individual figure to produce a total.

Key fields

A database should always contain a key field.

The key field is a unique identifier for each record.

The following are examples of key fields:

  • car registration number
  • National Insurance number
  • your school's examination centre number
  • your own examination candidate number

Storing data in tables

Databases store data in tables, a single database file can store many tables, queries and reports. In the example table below there are six columns (divided vertically) and four rows (divided horizontally), each column has a heading, eg Registration number.

 

Registration numberMakeModelDate first registeredPriceTaxed
R623 PHMFordFiesta0101986800Y
P887 LHWRover2000103977500Y
P812 WHJPeugeot4060109967000N

A database in which all the data is stored in a single table is known as a flat file database.

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