begin
 with Engine do begin
  with Functions.CreateFunction(ftBoolean, 'HasEmployees').Params do begin
   CreateFunctionParam(ftString); // field
   CreateFunctionParam(ftString); // test
   CreateFunctionParam(ftString); //phone no
  end;
  OnCustomFunction := CustomFunction;
 end;
 companies.Open;
 companies.filter :=  'HasEmployees(_Company,''= False'','''') ';
 companies.filtered:=true;
end;

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 Comments and Workarounds

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The workaround is to use the following expression instead:

companies.filter := 'HasEmployees(_Company,''= False'','''')=True';

The problem was that DBISAM was not properly handling custom functions that returned Boolean values.

---

 Resolution

---

Fixed Problem on 9/14/2005 in version 4.21 build 11

---

 Products Affected

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DBISAM VCL Client-Server
DBISAM VCL Client-Server with Source
DBISAM VCL Standard
DBISAM VCL Standard with Source