diff --git a/src/opt/hdf5/include/h5_group.cc.h b/src/opt/hdf5/include/h5_group.cc.h
index a50c64c..f8f9971 100644
--- a/src/opt/hdf5/include/h5_group.cc.h
+++ b/src/opt/hdf5/include/h5_group.cc.h
@@ -14,19 +14,20 @@ namespace CNORXZ
 	{
 	    auto i = this->getIndexTo(name);
 	    auto tab = std::dynamic_pointer_cast<Table>( *i );
+	    CXZ_ASSERT(tab->type() == ContentType::TABLE,
+		       "element '" << name << "' is not of type TABLE");
 	    if(tab == nullptr){
 		auto stab = std::dynamic_pointer_cast<STable<Ts...>>(*i);
 		CXZ_ASSERT(stab != nullptr, "wrong format for table '" << name << "'");
 		return stab;
 	    }
 	    else {
-		const RangePtr fields = tab->fields();
 		(*i)->close();
-		*i = std::make_shared<STable<Ts...>>(name, this, fields);
-		return *i;
+		auto stab = std::make_shared<STable<Ts...>>(name, this);
+		*i = stab;
+		return stab;
 	    }
 	}
-
 	
 	template <typename T>
 	Group& Group::addData(const String& name, const ArrayBase<T>& data)
@@ -38,7 +39,7 @@ namespace CNORXZ
 
 	template <typename... Ts>
 	Group& Group::addTable(const String& name, const ArrayBase<Tuple<Ts...>>& data,
-			       const Vector<String>& fnames)
+			       const Arr<String,sizeof...(Ts)>& fnames)
 	{
 	    CXZ_ASSERT(this->isOpen(), "tried to extend closed group");
 	    Vector<String> nvec({name});
diff --git a/src/opt/hdf5/include/h5_group.h b/src/opt/hdf5/include/h5_group.h
index afee4b1..babb886 100644
--- a/src/opt/hdf5/include/h5_group.h
+++ b/src/opt/hdf5/include/h5_group.h
@@ -40,7 +40,7 @@ namespace CNORXZ
 
 	    template <typename... Ts>
 	    Group& addTable(const String& name, const ArrayBase<Tuple<Ts...>>& data,
-			    const Vector<String>& fnames);
+			    const Arr<String,sizeof...(Ts)>& fnames);
 
 	    template <class F>
 	    decltype(auto) iter(F&& f) const;
diff --git a/src/opt/hdf5/include/h5_table.cc.h b/src/opt/hdf5/include/h5_table.cc.h
index 5e4c4d9..2072bd6 100644
--- a/src/opt/hdf5/include/h5_table.cc.h
+++ b/src/opt/hdf5/include/h5_table.cc.h
@@ -18,36 +18,13 @@ namespace CNORXZ
 	}
 
 	template <typename... Ts>
-	STable<Ts...>::STable(const String& name, const ContentBase* _parent,
-			      const Vector<String>& fnames) :
+	STable<Ts...>::STable(const String& name, const ContentBase* _parent) :
 	    Table(name, _parent)
 	{
 	    constexpr SizeT N = sizeof...(Ts);
 	    if(mFields == nullptr){
-		CXZ_ASSERT(fnames.size() != 0, "field names have to be initialized");
-		Vector<FieldID> fields(fnames.size());
-		for(SizeT i = 0; i != fields.size(); ++i){
-		    fields[i].first = i;
-		    fields[i].second = fnames[i];
-		}
-		mFields = URangeFactory<FieldID>(fields).create();
-	    }
-	    CXZ_ASSERT(mFields->size() == sizeof...(Ts), "expected tuple of size = " << mFields->size()
-		       << ", got: " << sizeof...(Ts));
 
-	    Tuple<Ts...> x;
-	    if(mRecords == nullptr) {
-		mOffsets = MArray<SizeT>( mFields, iter<0,N>
-		    ( [&](auto i) { return getTupleOffset(x, i); },
-		      [](const auto&... e) { return Vector<SizeT>({e...}); }) );
-		mSizes = MArray<SizeT>( mFields, iter<0,N>
-		    ( [&](auto i) { return sizeof(std::get<i>(x)); },
-		      [](const auto&... e) { return Vector<SizeT>({e...}); }) );
-		mTypes = MArray<hid_t>( mFields, iter<0,N>
-		    ( [&](auto i) { return getTypeId(std::get<i>(x)); },
-		      [](const auto&... e) { return Vector<hid_t>({e...}); }) );
-	    }
-	    else {
+		Tuple<Ts...> x;
 		iter<0,N>( [&](auto i) { CXZ_ASSERT
 			    ( getTupleOffset(x, i) == mOffsets.data()[i],
 			      "wrong offset for field " << i << ": " << getTupleOffset(x, i)
@@ -61,6 +38,48 @@ namespace CNORXZ
 			      "wrong type for field " << i << ": " << getTypeId(std::get<i>(x))
 			      << " vs " << mTypes.data()[i] ); }, NoF{} );
 	    }
+	    else {
+		CXZ_ASSERT(mFields->size() == N, "expected tuple of size = " << mFields->size()
+			   << ", got: " << N);
+	    }
+	}
+
+	template <typename... Ts>
+	STable<Ts...>::STable(const String& name, const ContentBase* _parent,
+			      const Arr<String,sizeof...(Ts)>& fnames) :
+	    Table(name, _parent)
+	{
+	    initFields(fnames);
+	}
+
+	template <typename... Ts>
+	STable<Ts...>& STable<Ts...>::initFields(const Arr<String,sizeof...(Ts)>& fnames)
+	{
+	    constexpr SizeT N = sizeof...(Ts);
+	    CXZ_ASSERT(mFields == nullptr and mRecords == nullptr,
+		       "tried to initialize an existing table");
+
+	    Vector<FieldID> fields(fnames.size());
+	    for(SizeT i = 0; i != fields.size(); ++i){
+		fields[i].first = i;
+		fields[i].second = fnames[i];
+	    }
+	    mFields = URangeFactory<FieldID>(fields).create();
+
+	    Tuple<Ts...> x;
+	    mOffsets = MArray<SizeT>
+		( mFields, iter<0,N>
+		  ( [&](auto i) { return getTupleOffset(x, i); },
+		    [](const auto&... e) { return Vector<SizeT>({e...}); }) );
+	    mSizes = MArray<SizeT>
+		( mFields, iter<0,N>
+		  ( [&](auto i) { return sizeof(std::get<i>(x)); },
+		    [](const auto&... e) { return Vector<SizeT>({e...}); }) );
+	    mTypes = MArray<hid_t>
+		( mFields, iter<0,N>
+		  ( [&](auto i) { return getTypeId(std::get<i>(x)); },
+		    [](const auto&... e) { return Vector<hid_t>({e...}); }) );
+	    return *this;
 	}
 
 	template <typename... Ts>
@@ -75,6 +94,14 @@ namespace CNORXZ
 	    }
 	    return *this;
 	}
+
+	template <typename... Ts>
+	MArray<Tuple<Ts...>> STable<Ts...>::read()
+	{
+	    MArray<Tuple<Ts...>> out(mRecords);
+	    //...!!!
+	    return out;
+	}
     }
 }
 
diff --git a/src/opt/hdf5/include/h5_table.h b/src/opt/hdf5/include/h5_table.h
index 8885230..6a9497b 100644
--- a/src/opt/hdf5/include/h5_table.h
+++ b/src/opt/hdf5/include/h5_table.h
@@ -46,8 +46,12 @@ namespace CNORXZ
 	{
 	public:
 	    DEFAULT_MEMBERS(STable);
-	    STable(const String& name, const ContentBase* _parent, const Vector<String>& fnames);
+	    STable(const String& name, const ContentBase* _parent);
+	    STable(const String& name, const ContentBase* _parent,
+		   const Arr<String,sizeof...(Ts)>& fnames);
 
+	    STable& initFields(const Arr<String,sizeof...(Ts)>& fnames);
+	    
 	    STable& appendRecord(const Tuple<Ts...>& t);
 	    STable& appendRecord(const MArray<Tuple<Ts...>>& t);
 
diff --git a/src/opt/hdf5/tests/h5_basic_unit_test.cc b/src/opt/hdf5/tests/h5_basic_unit_test.cc
index 1221aaa..603ba27 100644
--- a/src/opt/hdf5/tests/h5_basic_unit_test.cc
+++ b/src/opt/hdf5/tests/h5_basic_unit_test.cc
@@ -55,7 +55,7 @@ namespace
 	String mFileName;
 	//Vector<String> mGrps;
 
-	Vector<String> mFs;
+	Arr<String,3> mFs;
 	MArray<Tuple<SizeT,Int,Double>> mTabA; 
     };
 
@@ -142,12 +142,13 @@ namespace
 
     TEST_F(Group_Test, ReadTable)
     {
+	typedef Tuple<SizeT,Int,Double> RecType;
+	
 	File h5f(mFileName, true);
 	h5f.open();
-	auto tab = h5f.getGroup("gr1")->open().getTable("tab1");
+	auto tab = h5f.getGroup("gr1")->open().getTable("tab1", RecType());
 	EXPECT_EQ(tab->fields()->size(), 3u);
 	EXPECT_EQ(tab->records()->size(), 5u);
-
 	
     }
 }