implemented sqlite fetch

include/matador/sql/record.hpp

@@ -23,15 +23,17 @@ public:
 
   record() = default;
   record(std::initializer_list<column> columns);
+  record(const record&) = default;
+  record& operator=(const record&) = default;
+  record(record&&) noexcept = default;
+  record& operator=(record&&) noexcept = default;
   ~record() = default;
 
   template<class Operator>
   void process(Operator &op)
   {
     for(auto &col : columns_) {
-      // Todo: Find a solution to handle a column with process
-      int todo{};
-      matador::utils::access::attribute(op, col.name().c_str(), todo, col.attributes());
+      col.process(op);
     }
   }
   template < typename Type >
@@ -43,10 +45,10 @@ public:
   void append(column col);
 
   [[nodiscard]] const column& at(const std::string &name) const;
-  const column& at(size_t index);
+  const column& at(size_t index) const;
 
   iterator find(const std::string &column_name);
-  const_iterator find(const std::string &column_name) const;
+  [[nodiscard]] const_iterator find(const std::string &column_name) const;
 
   iterator begin();
   [[nodiscard]] const_iterator begin() const;
@@ -57,6 +59,8 @@ public:
   [[nodiscard]] const_iterator cend() const;
 
   [[nodiscard]] size_t size() const;
+  [[nodiscard]] bool empty() const;
+  void clear();
 
 private:
   column_by_index columns_;