diff --git a/src/lib/stat/data.hpp b/src/lib/stat/data.hpp
index 65dcfbf13..1478116d9 100644
--- a/src/lib/stat/data.hpp
+++ b/src/lib/stat/data.hpp
@@ -71,6 +71,8 @@
  ** 
  ** std::vector<int>& counters = daz.n.data;
  ** \endcode
+ ** 
+ ** @see DataCSV_test
  **
  */
 
@@ -240,7 +242,7 @@ namespace stat{
       fs::path filename_;
       
     public:
-      DataFile(fs::path csvFile)
+      DataFile(fs::path csvFile ="")
         : filename_{fs::consolidated (csvFile)}
         {
           loadData();
@@ -334,6 +336,9 @@ namespace stat{
       save (size_t lineLimit =std::numeric_limits<size_t>::max()
            ,bool backupOld =false)
         {
+          if (filename_.empty())
+            throw error::Logic{"Unable to save DataFile without filename given."};
+          
           fs::path newFilename{filename_};
           newFilename += ".tmp";
           
@@ -355,6 +360,22 @@ namespace stat{
         }                // lock onto absolute path
       
       
+      void
+      saveAs (fs::path newStorage
+             ,size_t lineLimit =std::numeric_limits<size_t>::max())
+        {
+          newStorage = fs::consolidated (newStorage);
+          if (fs::exists(newStorage))
+            throw error::Invalid{_Fmt{"Storing DataFile rejected: target %s exists already"}
+                                     % newStorage};
+          if (not (newStorage.parent_path().empty()
+                   or fs::exists(newStorage.parent_path())))
+            throw error::Invalid{_Fmt{"DataFile(%s) placed into nonexistent directory %s"}
+                                     % newStorage.filename() % newStorage.parent_path()};
+          filename_ = newStorage;
+          save (lineLimit);
+        }
+      
       
     private: /* === Implementation === */
       
diff --git a/tests/library/stat/data-csv-test.cpp b/tests/library/stat/data-csv-test.cpp
index e04135bbd..a72c54cec 100644
--- a/tests/library/stat/data-csv-test.cpp
+++ b/tests/library/stat/data-csv-test.cpp
@@ -31,11 +31,13 @@
 //#include "lib/time/timevalue.hpp"
 //#include "lib/error.hpp"
 //#include "lib/util-foreach.hpp"
+#include "lib/util.hpp"
 #include "lib/format-cout.hpp"            ///////////////////////TODO
 #include "lib/test/diagnostic-output.hpp" ///////////////////////TODO
 
 //#include <functional>
-//#include <string>
+#include <string>
+#include <vector>
 
 //using lumiera::Error;
 //using lumiera::LUMIERA_ERROR_EXCEPTION;
@@ -45,21 +47,37 @@
 
 //using boost::algorithm::is_lower;
 //using boost::algorithm::is_digit;
+using util::isnil;
 //using std::function;
-//using std::string;
+using std::string;
+using std::vector;
 
 
 namespace lib {
 namespace stat{
 namespace test{
   
-  template<class T>
-  class Wrmrmpft
+  namespace {//Setup for test
+    
+    /** Define the layout of a data row */
+    struct TableForm
     {
-      T tt_;
+        Column<string>  id{"ID"};
+        Column<double> val{"Value"};
+        Column<int>    off{"Offset"};
+    
+        auto allColumns()
+        {   return std::tie(id
+                           ,val
+                           ,off
+                           );
+        }
     };
+    
+    using TestTab = DataFile<TableForm>;
+    
+  }//(End)Test setup
   
-  struct Murpf { };
   
   
   /***********************************************************//**
@@ -74,17 +92,43 @@ namespace test{
       void
       run (Arg)
         {
+          simpleUsage();
           checkGarbageStr();
-          checkTypeDisplay();
           checkThrowChecker();
           checkLocalManipulation();
         }
       
       
-      /** @test prints "sizeof()" including some type name. */
+      /** @test add rows and data to a table without filename. */
       void
-      checkTypeDisplay ()
+      simpleUsage ()
         {
+          TestTab tab;
+          CHECK (isnil (tab));
+          tab.newRow();
+          CHECK (not isnil (tab));
+          CHECK (1 == tab.size());
+          CHECK ( "" == string{tab.id});
+          CHECK (0.0 == tab.val);
+          CHECK ( 0  == tab.off);
+          tab.id = "one";
+          tab.val = 1.0;
+          
+          tab.dupRow();
+          CHECK (2 == tab.size());
+          CHECK ("one" == string{tab.id});
+          CHECK ( 1.0  == tab.val);
+          CHECK (   0  == tab.off);
+          
+          tab.id = "two";
+          tab.val = 5.0;
+          tab.off = -23;
+          CHECK ("two" == string{tab.id});
+          CHECK ( 5.0  == tab.val);
+          CHECK ( -23  == tab.off);
+          
+          CHECK (tab.off.header == "Offset");
+          CHECK (tab.off.data   == vector({0,-23}));
         }
       
       
@@ -93,6 +137,7 @@ namespace test{
       void
       checkGarbageStr()
         {
+          UNIMPLEMENTED("Rabäääääh");
         }
       
       
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 2518782c3..0d2ab6ca6 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -112041,6 +112041,29 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <icon BUILTIN="flag-yellow"/>
 </node>
 </node>
+<node CREATED="1710351128227" ID="ID_1587957134" MODIFIED="1710351136356" TEXT="Erg&#xe4;nzungen">
+<icon BUILTIN="idea"/>
+<node COLOR="#338800" CREATED="1710351138211" ID="ID_424130600" MODIFIED="1710351150207" TEXT="Hilfsfunktionen zum Feststellen der Permissions einer Datei">
+<icon BUILTIN="button_ok"/>
+</node>
+<node COLOR="#338800" CREATED="1710351151183" ID="ID_1693319710" MODIFIED="1710352549516" TEXT="DataFile kann auch leer verwendet werden">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      Das ist naheliegend und kompromittiert das Design nicht wesentlich; File-Operationen k&#246;nnen ohnehin immer Fehler ausl&#246;sen, und da ein Pfad invalid sein kann, ist auch das Original-Design der Tabelle in dieser Hinsicht inh&#228;rent stateful.
+    </p>
+  </body>
+</html>
+</richcontent>
+<linktarget COLOR="#254cae" DESTINATION="ID_1693319710" ENDARROW="Default" ENDINCLINATION="138;10;" ID="Arrow_ID_1520501008" SOURCE="ID_101637286" STARTARROW="None" STARTINCLINATION="112;7;"/>
+<icon BUILTIN="yes"/>
+<node COLOR="#435e98" CREATED="1710351177329" ID="ID_1224481019" MODIFIED="1710352477647" TEXT="leer-Check vor Speichern"/>
+<node COLOR="#435e98" CREATED="1710351185059" ID="ID_431256200" MODIFIED="1710352477645" STYLE="fork" TEXT="saveAs()-Funktion bereistellen"/>
+</node>
+</node>
 <node BACKGROUND_COLOR="#ccb59b" COLOR="#6e2a38" CREATED="1710169538785" HGAP="-5" ID="ID_1706582137" MODIFIED="1710169562437" VSHIFT="16">
 <richcontent TYPE="NODE"><html>
   <head/>
@@ -112077,6 +112100,13 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1710163662386" ID="ID_694159551" MODIFIED="1710170478456" TEXT="DataCSV_test">
 <icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1710351225837" ID="ID_1756484657" MODIFIED="1710352395458" TEXT="simpleUsage">
+<icon BUILTIN="button_ok"/>
+<node COLOR="#435e98" CREATED="1710352396692" ID="ID_101637286" MODIFIED="1710352560707" TEXT="f&#xfc;hre hiermit Tabellen ohne File-Storage ein">
+<arrowlink COLOR="#254cae" DESTINATION="ID_1693319710" ENDARROW="Default" ENDINCLINATION="138;10;" ID="Arrow_ID_1520501008" STARTARROW="None" STARTINCLINATION="112;7;"/>
+<icon BUILTIN="yes"/>
+</node>
+</node>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1710163672834" ID="ID_778295326" MODIFIED="1710170479867" TEXT="Statistic_test">
 <icon BUILTIN="flag-yellow"/>