SET FILTER

Hide records not meeting a condition

Syntax

      SET FILTER TO [<lCondition>]

Arguments

TO <lCondition> is a logical expression that defines a specific set of current work area records accessible for processing.

SET FILTER TO without an argument deactivates the filter condition.

Description

When a FILTER condition is SET, the current work area acts as if it contains only the records that match the specified condition. A filter condition is one of the properties of a work area. Once a FILTER has been SET, the condition can be returned as a character string using the DBFILTER() function.

Most commands and functions that move the record pointer honor the current filter with the exception of those commands that access records by record number. This includes GOTO, commands specified with the RECORD clause, and RELATIONs linked by numeric expression to a work area with no active index.

Once a FILTER is SET, it is not activated until the record pointer is moved from its current position. You can use GO TOP to activate it.

As with SET DELETED, a filter has no effect on INDEX and REINDEX.

Note

Although SET FILTER makes the current work area appear as if it contains a subset of records, it, in fact, sequentially processes all records in the work area. Because of this, the time required to process a filtered work area will be the same as an unfiltered work area.

Examples

      .  This example filters Employee.dbf to only those records where
         the age is greater than 50:

      USE Employee INDEX Name NEW
      SET FILTER TO Age > 50
      LIST Lastname, Firstname, Age, Phone
      SET FILTER TO

Seealso

DBFILTER(), DBSETFILTER(), SET DELETED