Perform Calculations (Cambridge (CIE) IGCSE ICT): Revision Note

Perform calculations

How do you perform calculations in a database?

• In a database, you can use arithmetic operations or numeric functions to perform calculations

• Calculated fields are fields that carry out a calculation based on other number fields in the database

  • For example, a 'products' table with a stock and unit_price fields

  • You could use a calculated field named stockvalue to calculate unit_price * stock

  • This calculation multiplies the price of each item by its quantity to find the total value of the stock

• Calculated controls are objects you place on forms or reports to display the result of an expression

  • For example, a form in a sales database where you input the QuantitySold and UnitPrice

  • A calculated control could be used to display the TotalSale

  • TotalSale = QuantitySold * UnitPrice

  • This displays the total sale on the form without storing it in the database

Using formulae and functions to perform calculations

• Databases allow you to use formulae and functions to perform calculations at run time

• This can include basic arithmetic operations: addition, subtraction, multiplication, and division

• For example, you have a discount field and you want to subtract it from the total cost, you could use a subtraction operation like this:

  • FinalCost = TotalCost - Discount

Aggregate functions

• You can also use aggregate functions to calculate statistical information about a set of records

• Some examples include:

• Remember that the actual syntax and function names might differ slightly depending on the specific database system being used.