How can i save Data from a Database using a Gui and for-loops / How to access a functions workspace

Hi dear Matlab experts, I got a problem saving data downloaded from a database using a GUI im currently working on.

The situation is: The user selects the dates and the data-names(signals) he wants and the gui saves them into Timearray and Signalarray.

What I wanna do is after hitting the gui button, collecting the signal-data of each day chosen as variables and save them to a .mat file named after that day. So if Timearray contains '20-Feb-2015' and '21-Feb-2015' and Signalarray 'Signal1' and 'Signal2', i want one 20-feb-2015.mat, with var 'Signal1' and 'Signal2' and the same with the 21-feb-2015.mat.

My Problem is, i cant save the data received from the DB into the functions WS. From where I could save the via for-loop collected variables to a mat file.

The download of the data itself works fine for me.

function pushbutton49_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton49 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global TimeTableFinal;

Timearray = get(TimeTableFinal, 'Data');
Signalarray = get(handles.ChosenSignalsBox, 'String');

size_TA = size(Timearray);
size_SA = size(Signalarray);

for c1=1:size_TA(1)

      BeginTicks = Timearray{c1,3};
      EndTicks = Timearray{c1,4};

      date_name = Timearray{c1,1};
      splitDate = strsplit(date_name, {' '}); %cut date_name to create a valid filename

      for c2=1:size_SA(1)

          signalname = Signalarray{c2};

          conn = database( *connection details* );
          setdbprefs('DataReturnFormat','numeric');

          sqlQuery = [*sql query string*];

          curs = exec(conn, sqlQuery);
          curs = fetch(curs);
          signal_data = curs.Data;

          assignin('base',signalname, signal_data);%renaming the the data containing variable 'signal_data' to its true name, provided by 'signalname'
  %         whos;

          close(curs);%closing cursor and connection
          close(conn);

%         if c2==1
%             save(splitDate{1}, signal_data)%first loop, create matfile with just recieved data
%         else
%             save(splitDate{1}, signal_data, '-append');%following loops, adding the just received data to already existing matfile
%         end
%         

      end;
    whos  

%     save(splitDate{1});     

end;

At first i had the idea with

save(splitDate{1});

which doesnt work because ML then saves all variables and creates somekind of copy in the splitDate{1}-named matfile.

Then i tried

         if c2==1
             save(splitDate{1}, signalname)
         else
             save(splitDate{1}, signalname, '-append');
         end

Wich should have saved the var 'signalname' to the specified matfile....but if I debug and enter a 'whos' its not even listed...so Matlab cant find it either.

Funny Thing is, the Data and the signals of the last round of the for-loop appears in my global workspace if i comment the saving parts.

Perfect would be a assign command, which assigns the variable to the functions workspace so i can use it directly.

What can i do? Thanks in advance!

Answer 1

[Mr Anderson]

Whoever comes across the same problem, I kinda found a solution myself. Even though most experienced programers dont like eval(), its doing the job on my problem.

Solution:

In every of the inner for-loops I reassign the data received from the DB to a variable named like specified in my Signalarray.

So it looks something like this:

          evalstring = [signalname ' = signal_data;'];
          eval(evalstring);

this creates a Variable named after 'signalname' in the functions Workspace which later can be saved using the if-loop ive already implemented.