Functions and Directives Functions and Directives

Function DbClearFilter() Foundation

Clears the filter setting in a work area.

Syntax
DbClearFilter() --> NIL
Return

The return value of DbClearFilter() is always NIL.

Description

If a filter is defined for a work area, it is cleared by the function DbClearFilter(). When the function is used without the alias operator, the filter in the current work area is cleared.

The command SET FILTER TO with no specified filter expression can be used instead of DbClearFilter(). SET FILTER TO is only effective in the current work area.

The visibility of records is affected by DbClearFilter(). The effect of a filter condition is described under the function DbSetFilter() and the command SET FILTER.

Examples
DbClearFilter() 
// In the example, a filter condition is defined for the customer 
// file on the basis of the telephone area code. The names 
// of the customers from four cities are then listed to a file and 
// the filter condition is removed. 

PROCEDURE Main 
   USE Customer INDEX CustA ALIAS Cu NEW 

   SET FILTER TO Trim( AREACODE ) $ "305,404,713,504" 
   ? "Customers in Miami, Atlanta, Houston and New Orleans" 
   LIST Cu->LastName, Cu->FirstName TO FILE Customer.lst 

   DbClearFilter() 

   USE 
RETURN
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