Passing a BLOB as a parameter causes an error: Operand type collision: image is incompatible with text

Question

I am working on Delphi 7+ SQL Server 2008 + ADO

I have a table with 4 fields

emp_id integer 
Name varchar(50) 
designation varchar(10) 
comment text

I am trying to insert data from Delphi

 with qryAdoEmployee do
        try
          if not prepared then Prepared := True;
          Parameters.ParamByName('emp_id').Value := 12345;
          Parameters.ParamByName('Name').Value := 'NAME';
          Parameters.ParamByName('designation').Value := 'NEWDesig' ;

so I tried the following line of code to insert data into a comment like ftBlob

          parameters.ParamByName('comment').Assign(Memo1.Lines);

with the above line of code, it inserts data into the database, but inserts invalid data such as "???5?????????????????????????"

therefore, spending some time on google, replacing the above line of code with

      Len := Length(Memo1.Lines.Text);
      Stream := TMemoryStream.Create;
      Stream.Write(Len, SizeOf(Len));
      Stream.Write(PChar(Memo1.Lines.Text)^, Len);
      parameters.ParamByName('comment').LoadFromStream(Stream,ftBlob);

Above piece of code throws an error Collision like Operand: image is incompatible with text

    ExecSQL;
    except on E:EDatabaseError do 
      MessageDlg(E.Message, mtError, [mbOK], 0);
    end;

Answer 1

SQL Server text ftMemo Delphi ( ftBlob).

, , DataType ftMemo, :

parameters.ParamByName('comment').DataType := ftMemo;

Value:

parameters.ParamByName('comment').Value := Memo1.Text;