[firebase-br] Armazenar arquivos pdf no banco

[marcelo luiz stefaniak - teflamar]

bom dia maycon,
acredito hoje, que gravando dentro do banco de dados seja a melhor maneira, 
ainda mais se vc tiver vários arquivos (acima de 1000).
gravando fora do banco, este fica menor, mas a pasta fica cheia de arquivos, 
e seu acesso, tanto quanto seu gerenciamente fica lento.

segue um exemplo, com 2 maneiras de salvar e recuperar dados do/para blob.
sds  marcelo luiz stefaniak-teflamar


unit blob1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, IBDatabase, IBCustomDataSet, IBQuery, Grids,
  DBGrids, OleCtnrs,
  dbtables,
  jpeg, ExtCtrls;
type
  TForm1 = class(TForm)
    btgravar1: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    btrecuperar1: TButton;
    DBGrid1: TDBGrid;
    gravar2: TButton;
    q2: TIBQuery;
    IBDatabase1: TIBDatabase;
    IBTransaction1: TIBTransaction;
    q2COD: TIntegerField;
    q2NOME: TIBStringField;
    q2BLOB1: TBlobField;
    q2NOME_ARQ: TIBStringField;
    DBGrid2: TDBGrid;
    DataSource1: TDataSource;
    btabrir: TButton;
    Button1: TButton;
    btrecuperar2: TButton;
    Image1: TImage;
    procedure btgravar1Click(Sender: TObject);
    procedure btrecuperar1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure gravar2Click(Sender: TObject);
    procedure btabrirClick(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure btrecuperar2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
  d : tibdatabase;
  q : TibQuery;
  t : tibtransaction;
  s : TDataSource;
implementation
uses util;
{$R *.dfm}
procedure TForm1.FormShow(Sender: TObject);
begin
  d:=tibdatabase.create(self);
  d.Params.loadfromfile('params.txt');
  d.LoginPrompt:=false;
  d.DatabaseName:='d:\temp\dados.fdb';
  d.connected:=true;
  t:=tibtransaction.create(self);
  t.DefaultDatabase:=d;
  d.DefaultTransaction:=t;
  q:=TibQuery.Create(self);
  q.Database:=d;
  q.SQL.text:='select * from teste';
  q.open;
  s:=tdatasource.create(self);
  s.DataSet:=q;
  dbgrid1.DataSource:=s;
end;

procedure TForm1.btgravar1Click(Sender: TObject);
begin
  t.StartTransaction;
  q.sql.text:='INSERT INTO TESTE (COD,NOME,NOME_ARQ,BLOB1) VALUES 
(0,:NOME,:NOME_ARQ,:BLOB1)';
  try
    q.parambyname('NOME').asstring:='Teste '+datetostr(now);
    q.parambyname('NOME_ARQ').asstring:=edit1.text;
    q.ParamByName('BLOB1').LoadFromFile(edit1.text,ftBlob);
    q.ExecSQL;
    t.Commit;
  except
  on e:exception do
     begin
       ShowMessage(e.message);
     end;
  end;
end;

procedure TForm1.btrecuperar1Click(Sender: TObject);
var blob: TBlobStream;
begin
  //blob := q.CreateBlobStream(q.fieldByName('BLOB1') as tblobfield, 
bmRead);
  //Blob := TBlobStream.Create(q.Fieldbyname('blob1') as TBlobField, 
bmRead);
  //Blob:= TBlobStream.Create(q.Fieldbyname('blob1'), bmReadWrite);
  //Blob:= TBlobStream.Create(q.FieldByName('blob1') as tblobfield, 
bmReadWrite);
  //Blob:= TBlobStream.Create(q2blob1, bmReadWrite);
  Blob := TBlobStream.Create(q2.Fieldbyname('blob1') as TBlobField, 
bmReadwrite);
  try
    blob.Seek(0, soFromBeginning);
    with TFileStream.Create('c:\temp\'+q2.fieldbyname('nome_arq').asstring, 
fmCreate) do
      try
        CopyFrom(blob, blob.Size)
      finally
        Free
      end;
  finally
    blob.Free
  end;
end;

procedure TForm1.gravar2Click(Sender: TObject);
var
  fs  : TFileStream;
begin
try
  fs := TFileStream.Create(edit1.text, fmOpenRead or fmShareDenyWrite);
  if t.InTransaction then t.commit;
  t.StartTransaction;
  q.sql.text:='INSERT INTO TESTE (COD,NOME,NOME_ARQ,BLOB1) VALUES 
(0,:NOME,:NOME_ARQ,:BLOB1)';
  q.parambyname('NOME').asstring:='Teste '+datetostr(now);
  q.parambyname('NOME_ARQ').asstring:=edit1.text;
  q.ParamByName('BLOB1').LoadFromstream(fs,ftBlob);
  q.ExecSQL;
  t.Commit;
except
  on e:exception do
     begin
       ShowMessage(e.message);
     end;
end;
  fs.Free
end;

procedure TForm1.btabrirClick(Sender: TObject);
begin
q2.active:=not q2.active;
end;

procedure TForm1.Button1Click(Sender: TObject);
var FileStream: TFileStream; {a temp file}
    BlobStream: TBlobStream; {the WMF Blob}
    filename:string;
begin
 {Create a blob stream for the WMF blob}
  BlobStream := TBlobStream.Create(q2blob1, bmRead);
  if BlobStream.Size = 0 then begin
   BlobStream.Free;
   Exit;
  end;
  FileName := q2nome_arq.asstring;
 {Create a temp file stream}
  FileStream := TFileStream.Create(FileName,
                                   fmCreate or fmOpenWrite);
 {Copy the blob to the temp file}
  FileStream.CopyFrom(BlobStream, BlobStream.Size);
 {Free the streams}
  FileStream.Free;
  BlobStream.Free;
 {Dispaly the image}
  Image1.Picture.Metafile.LoadFromFile(FileName);
end;

procedure TForm1.btrecuperar2Click(Sender: TObject);
var
    warquivo   :string;
    BlobStream : TStream;
    FileStream : TFileStream;
begin
    filestream:=nil;
    blobstream:=nil;
    warquivo:='c:\temp\'+q2.fieldbyname('nome_arq').asstring;
  try
    BlobStream := q2.CreateBlobStream(q2.FieldByName('blob1'),bmRead);
    FileStream := TFileStream.Create(warquivo, fmCreate or fmOpenWrite);
    FileStream.CopyFrom(BlobStream, 0);
  finally
    blobstream.free;
    filestream.Free;
    execfile(warquivo);
    // Liberando memoria
  end;
end;

end.