Function DbFilter() Foundation
Returns the filter condition currently set for a work area.
DbFilter() --> cFilterExpressionThe return value of the function DbFilter() is a character string indicating the filter condition set for a work area. If no filter condition is in place, a null string ("") is returned.
If a filter condition is defined for a work area, it is returned by the function DbFilter(). When the function is used without the alias operator, the filter condition for the current work area is returned. The function returns the filter expression as a character string.
DbFilter() is used to determine the filter condition set in a work area so that it can be saved and later restored. For example, this is used with applications providing a "Query by Example" (QBE) that allows the user to define the filter condition at runtime of the program. Since the filter condition is returned as a character string, it can be saved in a database file. In this way a user-defined views can be managed.
// In the example, a filter condition is defined for a
// customer file and is read with DbFilter().
PROCEDURE Main
USE Customer NEW
SET FILTER TO Upper(Trim(CITY)) $ "TOLEDO,CLEVELAND"
? DbFilter() // result: Upper(Trim(CITY)) $ "TOLEDO,CLEVELAND"
DbClearFilter()
USE
RETURN
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.