Refactor that fixes a compilation issue in Release mode

Some template specialization were not found, because they were not declared
at the point they were used.

We moved things around, things are less inter-dependant, and also now it
works.

src/database/save.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <database/update_query.hpp>
+#include <database/insert_query.hpp>
+
+#include <database/engine.hpp>
+
+#include <database/row.hpp>
+
+#include <utils/is_one_of.hpp>
+
+template <typename... T, bool Coucou=true>
+void save(Row<T...>& row, DatabaseEngine& db, typename std::enable_if<!is_one_of<Id, T...> && Coucou>::type* = nullptr)
+{
+  insert(row, db);
+}
+
+template <typename... T, bool Coucou=true>
+void save(Row<T...>& row, DatabaseEngine& db, typename std::enable_if<is_one_of<Id, T...> && Coucou>::type* = nullptr)
+{
+  const Id& id = std::get<Id>(row.columns);
+    if (id.value == Id::unset_value)
+      {
+        insert(row, db);
+        if (db.last_inserted_rowid >= 0)
+          std::get<Id>(row.columns).value = static_cast<Id::real_type>(db.last_inserted_rowid);
+      }
+    else
+      update(row, db);
+}
+