Datenbank realisieren, aber ohne Server und Treiber ?

[barf00s]

hmm ich schreib dir erstmaln beispiel her wie ichs >dann< machen würde ...

Delphi-Quellcode:

uses
  Classes,  // TStream
  Contnrs;  // TObjectList

type
  TDatensatz = class
  private
    FSpalte1: string;  // oder machst aus allem nen string, je nachdem wie deine datensaetze aufgebaut werden sollen
    FSpalte2: integer;
    FSpalte3: double;
  public
    procedure LoadFromStream(Stream: TStream);
    procedure SaveToStream(Stream: TStream);
  property
    Spalte1: string read FSpalte1 write FSpalte1; // oder string read FSpalte1 write SetSpalte1; - dann müsstest dir noch private procedure SetSpalte1(const Value: string); reinbasteln
//    SpalteX...
  end;

  TDatensaetze = class(TObjectList)
  private
    function GetItems(Index: integer): TDatensatz;
    procedure SetItems(Index: integer; const Value: TDatensatz);
  public
    procedure LoadFromFile(const FileName: string);
    procedure LoadFromStream(Stream: TStream);
    procedure SaveToFile(const FileName: string);
    procedure SaveToStream(Stream: TStream);
    property Items[Index: integer]: TDatensatz read GetItems write SetItems; default;
  end;

implementation

procedure WriteStringToStream(Stream: TStream; const sText: string);
begin
  Stream.Write(Length(sText), 4); // 4 = SizeOf(Integer);
  Stream.Write(Pointer(sText)^, Length(sText));
// oder Stream.Write(sText[1], Length(sText));
end;

procedure ReadStringFromStream(Stream: TStream; var sText: string);
var
  iLength: integer;

begin
  Stream.Read(iLength, 4);
  SetLength(sText, iLength);
  Stream.Read(Pointer(sText)^, iLength);
// oder wieder Stream.Read(sText[1], iLength);
end;

{ TDatensatz }

procedure TDatensatz.LoadFromStream(Stream: TStream);
begin
  WriteStringToStream(Stream, FSpalte1);
  Stream.Write(FSpalte2, 4); // 4 = SizeOf(Integer)
  Stream.Write(FSpalte3, 8); // 8 = SizeOf(Double)
end;

procedure TDatensatz.SaveToStream(Stream: TStream);
begin
  ReadStringFromStream(Stream, FSpalte1);
  Stream.Read(FSpalte2, 4);
  Stream.Read(FSpalte3, 8);
end;

{ TDatensaetze }

function TDatensaetze.GetItems(Index: integer): TDatensatz;
begin
  if (Index > -1) and (Index < Count) then
    Result := TDatensatz(inherited Items[Index])
  else
    Result := nil;
end;

procedure TDatensaetze.LoadFromFile(const FileName: string);
var
  xFS: TFileStream;

begin
  if not FileExists(FileName) then
    Exit;
  xFS := TFileStream.Create(FileName, fmOpenRead or fmShareDenyNone);
  try
    LoadFromStream(xFS);
  finally
    FreeAndNil(xFS);
  end;
end;

procedure TDatensaetze.LoadFromStream(Stream: TStream);
var
  iCount: integer;
  iIndex: integer;
  xDatensatz: TDatensatz;

begin
  Stream.Read(iCount, 4);
  for iIndex := 0 to iCount - 1 do begin
    xDatensatz := TDatensatz.Create;
    xDatensatz.LoadFromStream(Stream);
    Add(xDatensatz);
  end;
end;

procedure TDatensaetze.SaveToFile(const FileName: string);
var
  xFS: TFileStream;

begin
  xFS := TFileStream.Create(FileName, fmCreate);
  try
    SaveToStream(xFS);
  finally
    FreeAndNil(xFS);
  end;
end;

procedure TDatensaetze.SaveToStream(Stream: TStream);
var
  iIndex: integer;

begin
  Stream.Write(Count, 4); // Count = Self.Count
  for iIndex := 0 to Count - 1 do
    Items[iIndex].SaveToStream(Stream);
end;

procedure TDatensaetze.SetItems(Index: integer; const Value: TDatensatz);
begin
  if (Index > -1) and (Index < Count) then
    Items[Index] := Value;
end;

p00h - ich hoffs iss soweit verständlich