unidac控件在SQLITE里怎么写入和读取BLOB类型的数据呀？

[cntigercat]

[kye_jufei]

这样声明。。。

type
   TServParams = TDAParams;
   TServParam = TDAParam;

[kye_jufei]

example:

1.先建立一个表，字段类型为blob:

SL.Add('CREATE TABLE IF NOT EXISTS TEST (');
SL.Add('FileName TEXT PRIMARY KEY,');
SL.Add('Data BLOB);');
SL.Add('');

2.写进二进制数据：

var
  FFileStream:TFileStream;
  FData:array of Char;
  FSQLR:TSQLRequest;
  ASQL:AnsiString;
begin
  FFileStream:=TFileStream.Create('test.xml',fmOpenReadWrite);
  ASQL:='INSERT INTO TEST(FileName,Data) VALUES('+QuotedStr('test.xml')+',?)';
  try
    SQLite数据库对象.Execute('DELETE FROM TEST');
    //
    SetLength(FData,FFileStream.Size);
    FFileStream.Position:=0;
    FFileStream.Read(PChar(FData)^,Length(FData));
    FSQLR.Prepare(SQLite数据库对象.DB,ASQL);
    FSQLR.Bind(1,PChar(FData),Length(FData));
    FSQLR.Execute;
  finally
    FreeAndNil(FFileStream);
  end;

Note:其中问号是参数,SQLite数据库对象类型为TSQLDataBase.

3.读取数据并写入到文件:

var
  FBlobField:TSQLBlobStream;
  FFileStream:TMemoryStream;
  FData:array of Char;
begin
  try
    FFileStream:=TMemoryStream.Create;
    FBlobField:=SQLite数据库对象.Blob('','TEST','Data',1,True);
    try
      FBlobField.Position:=0;
      SetLength(FData,FBlobField.Size);
      FBlobField.ReadBuffer(PChar(FData)^,FBlobField.Size);
      FFileStream.Write(PChar(FData)^,FBlobField.Size);
      FFileStream.SaveToFile("test.xml");
    finally
      FreeAndNil(FBlobField);
      FreeAndNil(FFileStream);
    end;
  except
    Result:='';
  end;

[nkym0626]

UniTable2.Open;
UniTable2.Append;
TBlobField(UniTable2.FieldByName('CONTENT')).LoadFromFile('d:\PackageRequires.exe');
UniTable2.Post;

UniQuery1.Close;
UniQuery1.SQL.Text := 'SELECT * FROM TESTBLOB WHERE ID=9';
UniQuery1.ExecSQL;
TBlobField(UniQuery1.FieldByName('CONTENT')).SaveToFile('d:\system\desktop\d.exe');