DataSnap Could not convert variant of type (Array Byte) into type (Integer)

[dlucic 1]

I have simple DataSnap server application with connection to MS SQL Server and also simple client application. On the server side I have TFDConnection object to connect to MS SQL Server. I also have TFDQuery with simple sql "insert into slika_test (slika) values (:slika)". Param slika is for image datatype in table test_slika. This is properties of Param slika of TFDQuery object

 

 

Of course, there is DataSetProvider object

 

On the client side I have TSQLConnection and DSProviderConnection object's. I connect to DataSnap server application with them. There is also TClientDataSet object

 

 

This is code for click on Button

 

 

I load image from Image1 object on the form into MemoryStream. Than I put that MemoryStream in Param of ClientDataSet object and execute. 

 

When I do that for the first time everything goes well. Data is stored in MS SQL table. But when I click it another time and same code executes I receive this error on the server application

 

 

Any body knows what is the problem?

 

 

 

 

 

 

[Remy Lebeau 1432]

3 hours ago, dlucic said:

 

You are not resetting ms.Position=0 before calling Param.LoadFromStream().

You are also leaking the TMemoryStream.

[dlucic 1]

16 hours ago, Remy Lebeau said:

You are not resetting ms.Position=0 before calling Param.LoadFromStream().

You are also leaking the TMemoryStream.

Thank you bu that is not my problem. I changed code as you tell me but I still have this massage
 

 

[Cristian Peța 107]

I would debug that TestDS server and see where the error occurs.

[dlucic 1]

Thanks again. If you wish I can send you compleate code for both applications. That is small peace of code for each of them. But you need a small MS SQL Database with one table with just to columns

[Jirka52 2]

What I see, that you want to put some image into SQL "insert" command.

If I try to save some blob, I every time use dataset field and call TClientdataset.ApplyUpdates.

Example:

//you wan to create new record therefore append

dodajslikujds.append;

try

  dodajslikujds.Fieldsbyname('here put correct fieldname').loadFromstream(ms);

 dodajslikujds.Post;
  var  I := dodajslikujds.ApplyUpdates(0);
   if (I <> 0) then
   begin
      raise Exception.Create('Data was not saved!');
    end; {if}

except

  dodajslikujds.Cancelupdates;

  raise;

end;

[dlucic 1]

1 hour ago, Jirka52 said:

What I see, that you want to put some image into SQL "insert" command.

If I try to save some blob, I every time use dataset field and call TClientdataset.ApplyUpdates.

Example:

//you wan to create new record therefore append

dodajslikujds.append;

try

  dodajslikujds.Fieldsbyname('here put correct fieldname').loadFromstream(ms);

 dodajslikujds.Post;
  var  I := dodajslikujds.ApplyUpdates(0);
   if (I <> 0) then
   begin
      raise Exception.Create('Data was not saved!');
    end; {if}

except

  dodajslikujds.Cancelupdates;

  raise;

end;

Thank you, it works fine now.