Comparing Large Files using SQLite (Not sure I'm doing this right)

#include <File.au3>
#include <SQLite.au3>
#include <SQLite.dll.au3>
Global $hQuery, $aRow, $fl_array2
Global $sTempDB = @ScriptDir & "\TempDB.db"
Global $iTotalCount = 0, $iTotalSoFar = 0
Global $iKey1_a = 1
Global $iKey1_b = 12
Global $iKey2_a = 18
Global $iKey2_b = 25
Global $st = TimerInit()
Global $iOrphans, $iDupes, $iMatches

; ---------------------------------------------
; Start SQLite
; ---------------------------------------------
_SQLite_Startup()
If @error Then
 ConsoleWrite('error loading sqlite.dll' & @LF)
 Exit
EndIf
If FileExists($sTempDB) Then FileDelete($sTempDB)
_SQLite_Open($sTempDB)
If @error Then
 ConsoleWrite('Unable to open DB' & @LF)
 _Exit()
EndIf
; ---------------------------------------------
; Get the files to compare
; ---------------------------------------------
$sFile1 = FileOpenDialog("Select EXTEST.DAT", @ScriptDir, "Dat files (*.dat)", 1 + 2, "")
If @error Then _Exit()
$sFile2 = FileOpenDialog("Select FSTEST.DAT", @ScriptDir, "Dat files (*.dat)", 1 + 2, "")
If @error Then _Exit()
; ---------------------------------------------
; Load the data from File2 into the db
; ---------------------------------------------
_ReLoad()
; ---------------------------------------------
; Compare the fields from File1 to those in File2
; ---------------------------------------------
CompareItems($sFile1)
; ---------------------------------------------
Func CompareItems($sFileContents)
 Dim $aSplit
 _FileReadToArray($sFileContents, $aSplit)
 If IsArray($aSplit) Then
  If $aSplit[1] = "" Then
   _ArrayDelete($aSplit, 1)
   $aSplit[0] -= 1
  EndIf
  $iTotalCount += $aSplit[0]
  For $i = 1 To $aSplit[0]
   $sPart1 = StringMid($aSplit[$i], $iKey1_a, ($iKey1_b - $iKey1_a) + 1)
   $sPart2 = StringMid($aSplit[$i], $iKey2_a, ($iKey2_b - $iKey2_a) + 1)
   If $sPart1 <> "" Then
    $iCount = 0
    _SQLite_Query(-1, 'select * from compare where PART1 = "' & $sPart1 & '" and PART2 = "' & $sPart2 & '";', $hQuery)
    While _SQLite_FetchData($hQuery, $aRow) = $SQLite_OK
     If $aRow[0] <> "" Then $iCount += 1
    WEnd
    ConsoleWrite($sPart1 & " $iCount = " & $iCount & @CRLF)
    If $iCount = 0 And $i <> $aSplit[0] Then
     $iOrphans += 1
    EndIf
    If $iCount = 1 Then
     $iMatches += 1
    EndIf
    If $iCount > 1 Then
     $iDupes += 1
    EndIf
   EndIf
   $iTotalSoFar += 1
  Next
  ConsoleWrite("---------------------------" & @CRLF)
  ConsoleWrite("Orphans: " & $iOrphans & @CRLF)
  ConsoleWrite("Matches: " & $iMatches & @CRLF)
  ConsoleWrite("Dupes: " & $iDupes & @CRLF)
  ConsoleWrite("Total: " & $iTotalCount & @CRLF)
 EndIf
EndFunc   ;==>CompareItems
Func _ReLoad()
 ; drop "parts" table if it exists, re-define and reload it
 If _SQLite_Exec(-1, 'drop table if exists compare;') <> $SQLite_OK Then
  ConsoleWrite('Drop table failed' & @LF)
  _Exit()
 Else
  ConsoleWrite('Compare table dropped for refresh' & @LF)
 EndIf
 If _SQLite_Exec(-1, 'create table compare (PART1, PART2);') <> $SQLite_OK Then
  ConsoleWrite('Create Table Failed' & @LF)
  _Exit()
 EndIf
 _FileReadToArray($sFile2, $fl_array2)
 Switch @error
  Case 1
   ConsoleWrite('Input file failed to open' & @LF)
   _Exit()
  Case 2
   ConsoleWrite('Unable to split file' & @LF)
   _Exit()
 EndSwitch
 Local $aLine, $sql
 ProgressOn('Loading Compare Table', 'Please Wait', '', Default, Default, 2 + 16); 2 - without always on top / 16 - Window can be moved
 _SQLite_Exec(-1, "begin immediate;")
 For $1 = 1 To $fl_array2[0]
  ProgressSet(($1 / $fl_array2[0]) * 100)
  $sql = 'insert into compare values ("' & _
    StringMid($fl_array2[$1], $iKey1_a, ($iKey1_b - $iKey1_a) + 1) & '", "' & _
    StringMid($fl_array2[$1], $iKey2_a, ($iKey2_b - $iKey2_a) + 1) & '");'
  If _SQLite_Exec(-1, $sql) <> $SQLite_OK Then
   ConsoleWrite('Table insert failed STMT = ' & $sql & @LF)
   _Exit()
  EndIf
 Next
 _SQLite_Exec(-1, "commit;")
 ProgressOff()
 ConsoleWrite('Table loaded with ' & UBound($fl_array2) - 1 & ' records in ' & Round(TimerDiff($st) / 1000, 3) & ' seconds' & @LF)
EndFunc   ;==>_ReLoad
Func _Exit()
 _SQLite_Close()
 _SQLite_Shutdown()
 Exit
EndFunc   ;==>_Exit