Read And Write A Blob Field Using FireDAC With Firemonkey On Android And IOS

If you’re using the FireDAC components that comes with Delphi XE5 Firemonkey and you want to save a bitmap or some other type of data to a blog field on your embedded database (either SQLite, IBlite, or Interbase To Go) it can be a bit tricky. For saving it is pretty standard fair with the TFDDataSet.LoadFromStream() which will load a stream like a memory stream into a field. The important piece to reading the blob back out is is the TFDDataSet.CreateBlobStream() function. I have included two functions below which show an example of how to read and write a string and bitmap data from an image using a FireDAC TFDQuery component. This method of reading and writing a blog works on Android and IOS as well as Windows and OSX.
procedure SaveToFireDACBlob;
var
MemStream: TMemoryStream;
begin
FireDAC.Connected := True;
MemStream := TMemoryStream.Create;
try
Image1.Bitmap.SaveToStream(MemStream);
MemStream.Seek(0,0);
FDQueryInsert.ParamByName('Media').LoadFromStream(MemStream,ftBlob);
FDQueryInsert.ParamByName('MType').AsString := '0';
FDQueryInsert.ExecSQL();
except
on e: Exception do
begin
//ShowMessage(e.Message);
end;
end;
MemStream.Free;
FireDAC.Connected := False;
end;

procedure LoadFromFireDACBlob;
var
BlobStream: TStream;
begin
FireDAC.Connected := True;
try
FDQuerySelect.Open;
FDQuerySelect.First;
while(not FDQuerySelect.EOF)do begin
// access a stream from a blob like this
BlobStream := FDQuerySelect.CreateBlobStream(FDQuerySelect.FieldByName('Media'),TBlobStreamMode.bmRead);
// access a string from a field like this
if (FDQuerySelect.FieldByName('MType').AsString='0') then
begin
// load your blob stream data into a control
ImageViewer.Bitmap.LoadFromStream(BlobStream);
end;
BlobStream.Free;
FDQuerySelect.Next;
end;
except
on e: Exception do
begin
//ShowMessage(e.Message);
end;
end;
FireDAC.Connected := False;
end;
Head over and check out the FireDAC demo from Embarcadero and then use the functions to read and write your blob data.

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