A boolean field or variable is one that only has two possible values, 1 and 0 (zero). On screen, boolean fields and variables are depicted using check boxes. A check box can be switched on or off: when it is switched on, the value of the variable is set to 1. Check boxes and boolean variables allow you to place simple yes/no choices in the specification window of your report.

Check boxes can initiate two types of searches: inclusive searches and exclusive searches. Exclusive searches start from the point where all records in a particular register will be listed in a report, and records are removed from the report if they meet the criteria controlled by the check boxes. For example, in a Customer List report, check boxes could be used to remove Closed Customers from the report, exclude Customers where a certain field is empty, or exclude Suppliers. Inclusive searches start from an empty report, and records are added to the report if they meet the criteria controlled by the check boxes. In this case, check boxes could be used to add Closed Customers into the report, include Customers where a certain field is empty, or include Suppliers.

When you place a check box in the specification window of a report (on the 'Input' card), you also need to add a "Selection:" line to the report display area on the 'Data' card. This "Selection:" line will contain a formula that determines what will happen when the check box is checked. This formula will consist of two parts: a test for the value of the check box, and the search that will then take place. In an exclusive search, these two parts are joined by "or". In an inclusive search, they are joined by "and".

Click for detailed descriptions of exclusive and inclusive searches. In both examples, we have not placed any variables in the specification windows. Variables can be used together with check boxes, as described on the Adding a Search page, with no variation.

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