## Summary `Locate` is a convenient method to seach for records in a dataset. `TDbf`, however, has an issue with it: it can find records with are not contained in the database. ## System Information - **Operating system:** Windows 11 - **Processor architecture:** x86-64 - **Compiler version:** 3.2.2, 3.3.1 - **Device:** Computer ## Steps to reproduce The following simple project creates a dBase file with a few country names. Searching for names which share the first character of the country name in existing records and otherwise are different is successful although such names are not in the database. ## Example Project ````pascal program project1; uses SysUtils, DB, DBF; const FILENAME = 'test.dbf'; var Dbf1: TDbf; procedure SearchFor(ACountryName: String); begin Write(' Searching for ', ACountryName); if Dbf1.Locate('Country', ACountryName, [loCaseInsensitive, loPartialKey]) then WriteLn(': found ', Dbf1.FieldByName('Country').AsString) else WriteLn(': not found'); end; begin if not DirectoryExists('data') then CreateDir('data'); Dbf1 := TDbf.Create(nil); Dbf1.FilePath := 'data'; Dbf1.TableName := FILENAME; if not FileExists(dbf1.FilePath + FILENAME) then begin // Create table Dbf1.TableLevel := 7; Dbf1.Exclusive := True; Dbf1.FieldDefs.Add('Country', ftString, 25, True); Dbf1.CreateTable; Dbf1.Open; // The following step is important: An index, even if not used, is required for the issue to appear. Dbf1.AddIndex('idxByCountry', 'Country', [ixCaseInsensitive]); // Add some data... Dbf1.AppendRecord(['Italy']); Dbf1.AppendRecord(['France']); Dbf1.AppendRecord(['Egypt']); Dbf1.AppendRecord(['Indonesia']); Dbf1.AppendRecord(['Austria']); end else Dbf1.Open; // Dbf1.IndexName := 'idxByCountry'; WriteLn('Country names in database:'); Dbf1.First; while not Dbf1.EoF do begin WriteLn(' ', Dbf1.FieldByName('Country').AsString); Dbf1.Next; end; WriteLn; WriteLn('Working:'); SearchFor('Austria'); SearchFor('It'); SearchFor('In'); WriteLn('But...'); SearchFor('Axyz'); SearchFor('Fxyz'); Dbf1.Close; Dbf1.Free; ReadLn; end. ```` ## What is the current bug behavior? This is the output of the project (built with Laz 3.2.2 or Laz 3.3.1). Note the last two lines which are not correct: Although the names "Axyz" and "Fxyz" are not listed in the db they are reported to be found ```` Country names in database: Italy France Egypt Indonesia Austria Working: Searching for Austria: found Austria Searching for It: found Italy Searching for In: found Indonesia But... Searching for Axyz: found Egypt Searching for Fxyz: found Indonesia ```` ## What is the expected (correct) behavior? ```` But... Searching for Axyz: not found Searching for Fxyz: not found ```` ## Possible fixes I wondered whether the "other" version of `TDbf` on SourceForce (https://sourceforge.net/projects/tdbf/) has the same issue: copied their sources into the project folder of my test program --> correct behaviour. In their svn commit history I found revision 579 __"Revert to linear search in LocateRecord when case insensitivity is requested"__ of Oct 15, 2015. Essentially this puts the current code of function `TDbf.LocateRecord` (unit `dbf.pas`) into an `if` block and calls `LocateRecordLinear` in the `else` part: ````pascal function TDbf.LocateRecord(const KeyFields: String; const KeyValues: Variant; Options: TLocateOptions): Boolean; var lCursor, lSaveCursor: TVirtualCursor; lSaveIndexName, lIndexName: string; lIndexDef: TDbfIndexDef; lIndexFile, lSaveIndexFile: TIndexFile; begin if not (loCaseInsensitive in Options) then begin // current code of LocateRecord here end else Result := LocateRecordLinear(KeyFields, KeyValues, Options); end; ```` See also this patch: [dbf-locate.diff](/uploads/4768e8970f3a845ff882dd7bc5059bfd/dbf-locate.diff) Applying this to the FPC version fixes the issue. Note that the original commit of r579 contains another modification ("Avoid access violation in SearchKeyPChar() when cursor is not a TIndexCursor"). This is not contained in my patch since I don't know how to reproduce that issue.