I can't send data to my mysql database

Hello,

In my code I try to send data towards mysql database, but the mysql database doesn't receive it. And the odd thing is that I don't get an error, so I don't know whats wrong. If someone could please check this out and help me! The code below is just a small part of the code I wrote, but in this small part is somewhere a mistake. The value send gives this out:

send =

struct with fields:

Message: 'Invalid connection.'

% --- Executes on button press in inputdata.
function inputdata_Callback(hObject, eventdata, handles)
% hObject    handle to inputdata (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
board= arduino();
b=0;

for i= 1:1:10
    analog= readVoltage (board, 'A0');
    writePWMVoltage (board, 'D3', analog);
    disp(['analog= ', num2str(analog)]);
    pause(1);
    
    A(i)= analog; 
   
    b= b+1;
    B(i)= b;
 
end

A=A';
B=B';

handles.voltage= A;
handles.pk= B;

handles.Data= [B A];

disp(handles.Data);

colnames= {'PK','Voltage'};
set(handles.uitable2,'data',handles.Data ,'ColumnName',colnames);

guidata(hObject, handles);

  function verstuur_Callback(hObject, eventdata, handles)
% hObject    handle to verstuur (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
gebruikersnaam= get(handles.edit_gebruikersnaam, 'String');
wachtwoord= get(handles.edit_wachtwoord, 'String');
datasource= get(handles.edit_tabel, 'String');

conn= database(datasource, gebruikersnaam, wachtwoord, handles.driver, handles.url);

Data1 =[handles.pk, handles.voltage];
columnnames = {'PK', 'Voltage'};
tablename = 'Data';
values = compose('VALUES(%d, %d)', Data1);  %note that the format depends on the type of data you insert %d works for INTEGER only
query = sprintf('InSERT INTO %s(%s) %s;', tablename, strjoin(columnnames, ', '), strjoin(values, ', '));

%query= ['INSERT INTO ' table ' VALUES (''''handles.Data'''')'];

send = exec(conn,query);

close (conn);