diff --git a/backends/sqlite/include/sqlite_prepared_result_reader.hpp b/backends/sqlite/include/sqlite_prepared_result_reader.hpp
index 9b55404..c90eff6 100644
--- a/backends/sqlite/include/sqlite_prepared_result_reader.hpp
+++ b/backends/sqlite/include/sqlite_prepared_result_reader.hpp
@@ -32,7 +32,7 @@ public:
   void read_value(const char *id, size_t index, char *value, size_t s) override;
   void read_value(const char *id, size_t index, std::string &value) override;
   void read_value(const char *id, size_t index, std::string &value, size_t s) override;
-  void read_value(const char *id, size_t index, sql::any_type &value, sql::data_type_t type, size_t size) override;
+  void read_value(const char *id, size_t index, sql::value &val, size_t size) override;
 
 private:
   sqlite3 *db_{nullptr};
diff --git a/backends/sqlite/src/sqlite_prepared_result_reader.cpp b/backends/sqlite/src/sqlite_prepared_result_reader.cpp
index 3097d52..ba6d528 100644
--- a/backends/sqlite/src/sqlite_prepared_result_reader.cpp
+++ b/backends/sqlite/src/sqlite_prepared_result_reader.cpp
@@ -107,8 +107,8 @@ void sqlite_prepared_result_reader::read_value(const char *id, size_t index, std
   query_result_reader::read_value(id, index, value, s);
 }
 
-void sqlite_prepared_result_reader::read_value(const char *id, size_t index, sql::any_type &value, sql::data_type_t type, size_t size)
+void sqlite_prepared_result_reader::read_value(const char *id, size_t index, sql::value &val, size_t size)
 {
-  query_result_reader::read_value(id, index, value, type, size);
+  query_result_reader::read_value(id, index, val, size);
 }
 }
\ No newline at end of file
diff --git a/backends/tests/SessionTest.cpp b/backends/tests/SessionTest.cpp
index 5a92a98..ceccf68 100644
--- a/backends/tests/SessionTest.cpp
+++ b/backends/tests/SessionTest.cpp
@@ -45,7 +45,7 @@ TEST_CASE_METHOD(SessionFixture, "Session relation test", "[session][relation]")
   REQUIRE(true);
 }
 
-TEST_CASE_METHOD(SessionFixture, "Find object with id", "[session][find]") {
+TEST_CASE_METHOD(SessionFixture, "Use session to find object with id", "[session][find]") {
   using namespace matador::test;
   ses.attach<airplane>("airplane");
   ses.create_schema();
diff --git a/include/matador/sql/data_type_traits.hpp b/include/matador/sql/data_type_traits.hpp
index 0c9f432..ef23b14 100644
--- a/include/matador/sql/data_type_traits.hpp
+++ b/include/matador/sql/data_type_traits.hpp
@@ -53,6 +53,15 @@ template < class Type, class Enable = void >
 struct data_type_traits;
 
 /// @cond MATADOR_DEV
+template <> struct data_type_traits<nullptr_t, void>
+{
+  inline static data_type_t builtin_type(std::size_t /*size*/) { return data_type_t::type_null; }
+  static void read_value(query_result_reader &reader, const char *id, size_t index, nullptr_t &/*value*/);
+  static void bind_value(parameter_binder &binder, size_t index, nullptr_t &/*value*/);
+  static void bind_result_value(result_parameter_binder &binder, size_t index, nullptr_t &/*value*/);
+  inline static any_type create_value(char &value) { return value; }
+};
+
 template <> struct data_type_traits<char, void>
 {
   inline static data_type_t builtin_type(std::size_t /*size*/) { return data_type_t::type_char; }
@@ -199,7 +208,7 @@ template <> struct data_type_traits<std::string, void>
 
 template <> struct data_type_traits<utils::blob, void>
 {
-  inline static data_type_t builtin_type(std::size_t size) { return data_type_t::type_blob; }
+  inline static data_type_t builtin_type(std::size_t /*size*/) { return data_type_t::type_blob; }
   static void read_value(query_result_reader &reader, const char *id, size_t index, utils::blob &value);
   static void bind_value(parameter_binder &binder, size_t index, utils::blob &value);
   static void bind_result_value(result_parameter_binder &binder, size_t index, utils::blob &value);
diff --git a/include/matador/sql/entity_query_builder.hpp b/include/matador/sql/entity_query_builder.hpp
index 31cb661..f6a1c29 100644
--- a/include/matador/sql/entity_query_builder.hpp
+++ b/include/matador/sql/entity_query_builder.hpp
@@ -6,6 +6,7 @@
 #include "matador/sql/query_context.hpp"
 #include "matador/sql/query.hpp"
 #include "matador/sql/query_intermediates.hpp"
+#include "matador/sql/value.hpp"
 
 #include <iostream>
 
@@ -24,20 +25,19 @@ struct entity_query_data {
   std::unique_ptr<basic_condition> where_clause;
 };
 
-template < typename PrimaryKeyType >
 class entity_query_builder
 {
 public:
-  explicit entity_query_builder(const PrimaryKeyType &pk, const schema &scm)
-  : pk_(pk)
-  , schema_(scm) {}
+  explicit entity_query_builder(const schema &scm)
+  : schema_(scm) {}
 
-  template<class EntityType>
-  std::optional<entity_query_data> build() {
+  template<class EntityType, typename PrimaryKeyType>
+  std::optional<entity_query_data> build(const PrimaryKeyType &pk) {
     const auto info = schema_.info<EntityType>();
     if (!info) {
       return std::nullopt;
     }
+    pk_ = pk;
     table_info_stack_.push(info.value());
     entity_query_data_ = { info->name };
     EntityType obj;
@@ -50,24 +50,13 @@ public:
   void on_primary_key(const char *id, V &, typename std::enable_if<std::is_integral<V>::value && !std::is_same<bool, V>::value>::type* = 0)
   {
     push(id);
-    if (is_root_entity() && std::is_integral_v<PrimaryKeyType>) {
-      entity_query_data_.where_clause = make_condition(column{table_info_stack_.top().name, id, ""} == pk_);
+    if (is_root_entity() && pk_.is_integer()) {
+      entity_query_data_.where_clause = make_condition(column{table_info_stack_.top().name, id, ""} == *pk_.as<V>());
     }
   }
 
-  void on_primary_key(const char *id, std::string &, size_t)
-  {
-    push(id);
-    if (!is_root_entity()) {
-      auto b = std::is_same_v<PrimaryKeyType, std::string>;
-      std::cout << "is matching primary key: " << std::boolalpha << b << "\n";
-    }
-  }
-
-  void on_revision(const char *id, unsigned long long &/*rev*/)
-  {
-    push(id);
-  }
+  void on_primary_key(const char *id, std::string &, size_t);
+  void on_revision(const char *id, unsigned long long &/*rev*/);
 
   template<typename Type>
   void on_attribute(const char *id, Type &, const utils::field_attributes &/*attr*/ = utils::null_attributes)
@@ -174,26 +163,12 @@ public:
   void on_has_many_to_many(const char *id, ContainerType &c, const utils::foreign_attributes &/*attr*/) {}
 
 private:
-  void push(const std::string &column_name)
-  {
-    char str[4];
-    snprintf(str, 4, "c%02d", ++column_index);
-    entity_query_data_.columns.emplace_back(table_info_stack_.top().name, column_name, str);
-  }
+  void push(const std::string &column_name);
+  [[nodiscard]] bool is_root_entity() const;
+  void append_join(const column &left, const column &right);
 
-  [[nodiscard]] bool is_root_entity() const {
-    return table_info_stack_.size() == 1;
-  }
-
-  void append_join(const column &left, const column &right)
-  {
-    entity_query_data_.joins.push_back({
-      { left.table },
-      make_condition(left == right)
-    });
-  }
 private:
-  PrimaryKeyType pk_;
+  value pk_;
   std::stack<table_info> table_info_stack_;
   const schema &schema_;
   entity_query_data entity_query_data_;
diff --git a/include/matador/sql/field.hpp b/include/matador/sql/field.hpp
index 0dcefdc..a749397 100644
--- a/include/matador/sql/field.hpp
+++ b/include/matador/sql/field.hpp
@@ -1,11 +1,7 @@
 #ifndef QUERY_FIELD_HPP
 #define QUERY_FIELD_HPP
 
-#include "matador/sql/any_type.hpp"
-#include "matador/sql/any_type_to_visitor.hpp"
-#include "matador/sql/data_type_traits.hpp"
-
-#include "matador/utils/types.hpp"
+#include "matador/sql/value.hpp"
 
 #include <optional>
 #include <string>
@@ -19,10 +15,8 @@ public:
   template<typename Type>
   field(std::string name, Type value, size_t size = 0, int index = -1)
   : name_(std::move(name))
-  , size_(size)
   , index_(index)
-  , value_(value)
-  , type_(data_type_traits<Type>::builtin_type(size)) {}
+  , value_(value, size) {}
   field(std::string name, data_type_t data_type, size_t size = 0, int index = -1);
   field(const field &x) = default;
   field& operator=(const field &x) = default;
@@ -32,7 +26,7 @@ public:
   template<typename Type>
   field& operator=(Type value) {
     value_ = std::move(value);
-    type_ = data_type_traits<Type>::builtin_type(-1);
+
     return *this;
   }
 
@@ -43,9 +37,7 @@ public:
   template<class Type>
   std::optional<Type> as() const
   {
-    any_type_to_visitor<Type> visitor;
-    std::visit(visitor, const_cast<any_type&>(value_));
-    return visitor.result;
+    return value_.as<Type>();
   }
 
   [[nodiscard]] std::string str() const;
@@ -65,7 +57,7 @@ private:
   template<class Operator>
   void process(Operator &op)
   {
-    op.on_attribute(name_.c_str(), value_, type_, size_);
+    op.on_attribute(name_.c_str(), value_, value_.size());
   }
 
 private:
@@ -73,9 +65,8 @@ private:
 
   std::string name_;
   int index_{-1};
-  any_type value_;
-  size_t size_{};
-  data_type_t type_;
+
+  value value_;
 };
 
 }
diff --git a/include/matador/sql/query_result_impl.hpp b/include/matador/sql/query_result_impl.hpp
index 334128e..581bdff 100644
--- a/include/matador/sql/query_result_impl.hpp
+++ b/include/matador/sql/query_result_impl.hpp
@@ -15,6 +15,8 @@
 
 namespace matador::sql {
 
+class value;
+
 namespace detail {
 class pk_reader
 {
@@ -74,7 +76,7 @@ public:
   }
   void on_attribute(const char *id, char *value, const utils::field_attributes &attr = utils::null_attributes);
   void on_attribute(const char *id, std::string &value, const utils::field_attributes &attr = utils::null_attributes);
-  void on_attribute(const char *id, any_type &value, data_type_t type, const utils::field_attributes &attr = utils::null_attributes);
+  void on_attribute(const char *id, value &val, const utils::field_attributes &attr = utils::null_attributes);
 
   template < class Pointer >
   void on_belongs_to(const char * /*id*/, Pointer &x, const utils::foreign_attributes &attr)
diff --git a/include/matador/sql/query_result_reader.hpp b/include/matador/sql/query_result_reader.hpp
index 915bfde..a18bf26 100644
--- a/include/matador/sql/query_result_reader.hpp
+++ b/include/matador/sql/query_result_reader.hpp
@@ -6,6 +6,8 @@
 
 namespace matador::sql {
 
+class value;
+
 class query_result_reader
 {
 public:
@@ -34,7 +36,7 @@ public:
   virtual void read_value(const char *id, size_t index, std::string &value);
   virtual void read_value(const char *id, size_t index, std::string &value, size_t s);
   virtual void read_value(const char *id, size_t index, utils::blob &value);
-  virtual void read_value(const char *id, size_t index, any_type &value, data_type_t type, size_t size);
+  virtual void read_value(const char *id, size_t index, value &val, size_t size);
 };
 
 }
diff --git a/include/matador/sql/session.hpp b/include/matador/sql/session.hpp
index eb6e629..8c41639 100644
--- a/include/matador/sql/session.hpp
+++ b/include/matador/sql/session.hpp
@@ -43,8 +43,8 @@ public:
       return {};
     }
 
-    entity_query_builder<PrimaryKeyType> eqb(pk, *schema_);
-    auto data = eqb.template build<Type>();
+    entity_query_builder eqb(*schema_);
+    auto data = eqb.build<Type>(pk);
 
     auto q = c->query(*schema_)
       .select(data->columns)
diff --git a/include/matador/sql/value.hpp b/include/matador/sql/value.hpp
new file mode 100644
index 0000000..c3ff003
--- /dev/null
+++ b/include/matador/sql/value.hpp
@@ -0,0 +1,81 @@
+#ifndef QUERY_VALUE_HPP
+#define QUERY_VALUE_HPP
+
+#include "matador/sql/any_type.hpp"
+#include "matador/sql/any_type_to_visitor.hpp"
+#include "matador/sql/data_type_traits.hpp"
+
+#include "matador/utils/types.hpp"
+
+#include <optional>
+
+namespace matador::sql {
+
+namespace detail {
+template<typename Type>
+size_t determine_size(const Type &/*val*/)
+{
+  return 0;
+}
+size_t determine_size(const std::string &val);
+size_t determine_size(const char *val);
+size_t determine_size(const utils::blob &val);
+
+}
+class value
+{
+public:
+  value() = default;
+  template<typename Type>
+  explicit value(Type value, size_t size = 0)
+  : size_(size)
+  , value_(value)
+  , type_(data_type_traits<Type>::builtin_type(size)) {}
+  explicit value(data_type_t data_type, size_t size = 0);
+  value(const value &x) = default;
+  value& operator=(const value &x) = default;
+  template<typename Type>
+  value& operator=(Type val)
+  {
+    value_ = val;
+    size_ = detail::determine_size(val);
+    type_ = data_type_traits<Type>::builtin_type(size_);
+    return *this;
+  }
+  value(value &&x) noexcept;
+  value& operator=(value &&x) noexcept;
+
+  template<class Type>
+  std::optional<Type> as() const
+  {
+    if (std::holds_alternative<Type>(value_)) {
+      return std::get<Type>(value_);
+    } else {
+      any_type_to_visitor<Type> visitor;
+      std::visit(visitor, const_cast<any_type &>(value_));
+      return visitor.result;
+    }
+  }
+  [[nodiscard]] std::string str() const;
+
+  [[nodiscard]] size_t size() const;
+  [[nodiscard]] data_type_t type() const;
+
+  [[nodiscard]] bool is_integer() const;
+  [[nodiscard]] bool is_floating_point() const;
+  [[nodiscard]] bool is_bool() const;
+  [[nodiscard]] bool is_string() const;
+  [[nodiscard]] bool is_varchar() const;
+  [[nodiscard]] bool is_blob() const;
+  [[nodiscard]] bool is_null() const;
+  [[nodiscard]] bool is_unknown() const;
+
+private:
+  any_type value_;
+  size_t size_{};
+  data_type_t type_{data_type_t::type_unknown};
+
+};
+
+}
+#endif //QUERY_VALUE_HPP
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8d730de..59839af 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -37,6 +37,8 @@ set(SQL_SOURCES
   sql/any_type_to_string_visitor.cpp
   sql/field.cpp
   sql/table_definition.cpp
+  sql/value.cpp
+  sql/entity_query_builder.cpp
 )
 
 set(SQL_HEADER
@@ -92,6 +94,7 @@ set(SQL_HEADER
   ../include/matador/sql/entity_query_builder.hpp
   ../include/matador/sql/table_definition.hpp
   ../include/matador/sql/has_many_to_many_relation.hpp
+  ../include/matador/sql/value.hpp
 )
 
 set(UTILS_HEADER
diff --git a/src/sql/column_definition.cpp b/src/sql/column_definition.cpp
index 4291d8f..97ad391 100644
--- a/src/sql/column_definition.cpp
+++ b/src/sql/column_definition.cpp
@@ -110,6 +110,10 @@ void column_definition::type(data_type_t type)
 
 std::string column_definition::str() const
 {
+  if (std::holds_alternative<std::string>(value_)) {
+    return std::get<std::string>(value_);
+  }
+
   any_type_to_visitor<std::string> visitor;
   std::visit(visitor, const_cast<any_type &>(value_));
   return visitor.result;
diff --git a/src/sql/data_type_traits.cpp b/src/sql/data_type_traits.cpp
index 69f134f..5fedc18 100644
--- a/src/sql/data_type_traits.cpp
+++ b/src/sql/data_type_traits.cpp
@@ -6,6 +6,21 @@
 
 namespace matador::sql {
 
+void data_type_traits<nullptr_t>::read_value(query_result_reader &reader, const char *id, size_t index, nullptr_t &/*value*/)
+{
+//  reader.read_value(id, index, value);
+}
+
+void data_type_traits<nullptr_t>::bind_value(parameter_binder &binder, size_t index, nullptr_t &/*value*/)
+{
+//  binder.bind(index, value);
+}
+
+void data_type_traits<nullptr_t>::bind_result_value(result_parameter_binder &binder, size_t index, nullptr_t &/*value*/)
+{
+//  binder.bind_result_value(index, value);
+}
+
 void data_type_traits<char>::read_value(query_result_reader &reader, const char *id, size_t index, char &value)
 {
   reader.read_value(id, index, value);
diff --git a/src/sql/dialect.cpp b/src/sql/dialect.cpp
index e11c4b9..07433b0 100644
--- a/src/sql/dialect.cpp
+++ b/src/sql/dialect.cpp
@@ -37,7 +37,7 @@ std::string dialect::prepare_identifier_string(const std::string &col) const
 
   for (auto &part : parts) {
     escape_quotes_in_identifier(part);
-//    quote_identifier(part);
+    quote_identifier(part);
   }
   return utils::join(parts, ".");
 }
diff --git a/src/sql/entity_query_builder.cpp b/src/sql/entity_query_builder.cpp
new file mode 100644
index 0000000..6d96555
--- /dev/null
+++ b/src/sql/entity_query_builder.cpp
@@ -0,0 +1,38 @@
+#include "matador/sql/entity_query_builder.hpp"
+
+namespace matador::sql {
+
+void entity_query_builder::on_primary_key(const char *id, std::string &, size_t)
+{
+  push(id);
+  if (!is_root_entity()) {
+    auto b = pk_.is_varchar();
+    std::cout << "is matching primary key: " << std::boolalpha << b << "\n";
+  }
+}
+
+void entity_query_builder::on_revision(const char *id, unsigned long long &/*rev*/)
+{
+  push(id);
+}
+
+void entity_query_builder::push(const std::string &column_name)
+{
+  char str[4];
+  snprintf(str, 4, "c%02d", ++column_index);
+  entity_query_data_.columns.emplace_back(table_info_stack_.top().name, column_name, str);
+}
+
+[[nodiscard]] bool entity_query_builder::is_root_entity() const {
+  return table_info_stack_.size() == 1;
+}
+
+void entity_query_builder::append_join(const column &left, const column &right)
+{
+  entity_query_data_.joins.push_back({
+                                       { left.table },
+                                       make_condition(left == right)
+                                     });
+}
+
+}
\ No newline at end of file
diff --git a/src/sql/field.cpp b/src/sql/field.cpp
index 229b9c1..c3364a0 100644
--- a/src/sql/field.cpp
+++ b/src/sql/field.cpp
@@ -7,24 +7,20 @@ namespace matador::sql {
 field::field(std::string name)
   : name_(std::move(name))
   , value_(nullptr)
-  , type_(data_type_t::type_unknown)
 {}
 
 field::field(std::string name, data_type_t data_type, size_t size, int index)
   : name_(std::move(name))
-  , size_(size)
   , index_(index)
-  , type_(data_type) {}
+  , value_(data_type, size) {}
 
 field::field(field &&x) noexcept
   : name_(std::move(x.name_))
   , index_(x.index_)
   , value_(std::move(x.value_))
-  , type_(x.type_)
 {
   x.value_ = nullptr;
   x.index_ = -1;
-  x.type_ = data_type_t::type_unknown;
 }
 
 field &field::operator=(field &&x) noexcept
@@ -32,10 +28,8 @@ field &field::operator=(field &&x) noexcept
   name_ = std::move(x.name_);
   index_ = x.index_;
   value_ = std::move(x.value_);
-  type_ = x.type_;
   x.index_ = -1;
   x.value_ = nullptr;
-  x.type_ = data_type_t::type_unknown;
 
   return *this;
 }
@@ -47,7 +41,7 @@ const std::string &field::name() const
 
 size_t field::size() const
 {
-  return size_;
+  return value_.size();
 }
 
 int field::index() const
@@ -68,42 +62,42 @@ std::string field::str() const
 
 bool field::is_integer() const
 {
-  return type_ >= data_type_t::type_char && type_ <= data_type_t::type_unsigned_long_long;
+  return value_.is_integer();
 }
 
 bool field::is_floating_point() const
 {
-  return type_ == data_type_t::type_float || type_ == data_type_t::type_double;
+  return value_.is_floating_point();
 }
 
 bool field::is_bool() const
 {
-  return type_ == data_type_t::type_bool;
+  return value_.is_bool();
 }
 
 bool field::is_string() const
 {
-  return type_ == data_type_t::type_text;
+  return value_.is_string();
 }
 
 bool field::is_varchar() const
 {
-  return type_ == data_type_t::type_varchar;
+  return value_.is_varchar();
 }
 
 bool field::is_blob() const
 {
-  return type_ == data_type_t::type_blob;
+  return value_.is_blob();
 }
 
 bool field::is_null() const
 {
-  return type_ == data_type_t::type_null;
+  return value_.is_null();
 }
 
 bool field::is_unknown() const
 {
-  return type_ == data_type_t::type_unknown;
+  return value_.is_unknown();
 }
 
 }
\ No newline at end of file
diff --git a/src/sql/query_result_impl.cpp b/src/sql/query_result_impl.cpp
index 76e2de4..a21ede0 100644
--- a/src/sql/query_result_impl.cpp
+++ b/src/sql/query_result_impl.cpp
@@ -1,5 +1,6 @@
 #include "matador/sql/query_result_impl.hpp"
 #include "matador/sql/query_result_reader.hpp"
+#include "matador/sql/value.hpp"
 
 namespace matador::sql {
 
@@ -39,9 +40,9 @@ void query_result_impl::on_attribute(const char *id, std::string &value, const u
 }
 
 void
-query_result_impl::on_attribute(const char *id, any_type &value, data_type_t type, const utils::field_attributes &attr)
+query_result_impl::on_attribute(const char *id, value &val, const utils::field_attributes &attr)
 {
-  reader_->read_value(id, column_index_++, value, type, attr.size());
+  reader_->read_value(id, column_index_++, val, attr.size());
 }
 
 const std::vector<column_definition>& query_result_impl::prototype() const
diff --git a/src/sql/query_result_reader.cpp b/src/sql/query_result_reader.cpp
index cf27589..79e7328 100644
--- a/src/sql/query_result_reader.cpp
+++ b/src/sql/query_result_reader.cpp
@@ -1,5 +1,6 @@
 #include "matador/sql/query_result_reader.hpp"
 #include "matador/sql/to_value.hpp"
+#include "matador/sql/value.hpp"
 
 namespace matador::sql {
 
@@ -104,82 +105,82 @@ void query_result_reader::read_value(const char *id, size_t index, utils::blob &
 }
 
 template < typename Type >
-void convert(const char *valstr, sql::any_type &value)
+void convert(const char *valstr, value &val)
 {
-  Type val{};
-  sql::to_value(val, valstr);
-  value = val;
+  Type local_val{};
+  sql::to_value(local_val, valstr);
+  val = local_val;
 }
 
-void query_result_reader::read_value(const char *id, size_t index, any_type &value, data_type_t type, size_t size)
+void query_result_reader::read_value(const char *id, size_t index, value &val, size_t size)
 {
-  switch (type) {
+  switch (val.type()) {
     case sql::data_type_t::type_char:
-      convert<char>(column(index), value);
+      convert<char>(column(index), val);
       break;
     case sql::data_type_t::type_short:
-      convert<short>(column(index), value);
+      convert<short>(column(index), val);
       break;
     case sql::data_type_t::type_int:
-      convert<int>(column(index), value);
+      convert<int>(column(index), val);
       break;
     case sql::data_type_t::type_long:
-      convert<long>(column(index), value);
+      convert<long>(column(index), val);
       break;
     case sql::data_type_t::type_long_long:
-      convert<long long>(column(index), value);
+      convert<long long>(column(index), val);
       break;
     case sql::data_type_t::type_unsigned_char:
-      convert<unsigned char>(column(index), value);
+      convert<unsigned char>(column(index), val);
       break;
     case sql::data_type_t::type_unsigned_short:
-      convert<unsigned short>(column(index), value);
+      convert<unsigned short>(column(index), val);
       break;
     case sql::data_type_t::type_unsigned_int:
-      convert<unsigned int>(column(index), value);
+      convert<unsigned int>(column(index), val);
       break;
     case sql::data_type_t::type_unsigned_long:
-      convert<unsigned long>(column(index), value);
+      convert<unsigned long>(column(index), val);
       break;
     case sql::data_type_t::type_unsigned_long_long:
-      convert<unsigned long long>(column(index), value);
+      convert<unsigned long long>(column(index), val);
       break;
     case sql::data_type_t::type_float:
-      convert<float>(column(index), value);
+      convert<float>(column(index), val);
       break;
     case sql::data_type_t::type_double:
-      convert<double>(column(index), value);
+      convert<double>(column(index), val);
       break;
     case sql::data_type_t::type_bool: {
-      int val{};
-      sql::to_value(val, column(index));
-      value = val > 0;
+      int local_val{};
+      sql::to_value(local_val, column(index));
+      val = local_val > 0;
       break;
     }
     case sql::data_type_t::type_text:
     case sql::data_type_t::type_varchar: {
-      value = std::string{column(index)};
+      val = std::string{column(index)};
       break;
     }
     case sql::data_type_t::type_char_pointer: {
-      value = column(index);
+      val = column(index);
       break;
     }
     case sql::data_type_t::type_time:
     case sql::data_type_t::type_date: {
-      value = std::string{column(index)};
+      val = std::string{column(index)};
       break;
     }
     case sql::data_type_t::type_null: {
-      value = nullptr_t{};
+      val = nullptr_t{};
       break;
     }
     case sql::data_type_t::type_blob: {
-      value = utils::blob{};
+      val = utils::blob{};
       break;
     }
     case sql::data_type_t::type_unknown: {
-      value = std::string(column(index));
+      val = std::string(column(index));
       break;
     }
   }
diff --git a/src/sql/value.cpp b/src/sql/value.cpp
new file mode 100644
index 0000000..cedc26b
--- /dev/null
+++ b/src/sql/value.cpp
@@ -0,0 +1,99 @@
+#include "matador/sql/value.hpp"
+
+namespace matador::sql {
+namespace detail {
+
+size_t determine_size(const std::string &val)
+{
+  return val.size();
+}
+
+size_t determine_size(const char *val)
+{
+  return strlen(val);
+}
+
+size_t determine_size(const utils::blob &val)
+{
+  return val.size();
+}
+
+}
+value::value(data_type_t data_type, size_t size)
+: size_(size)
+, type_(data_type) {}
+
+value::value(value &&x) noexcept
+  : value_(std::move(x.value_))
+  , type_(x.type_)
+{
+  x.value_ = nullptr;
+  x.type_ = data_type_t::type_unknown;
+}
+
+value &value::operator=(value &&x) noexcept
+{
+  value_ = std::move(x.value_);
+  type_ = x.type_;
+  x.value_ = nullptr;
+  x.type_ = data_type_t::type_unknown;
+
+  return *this;
+}
+
+std::string value::str() const
+{
+  return as<std::string>().value();
+}
+
+size_t value::size() const
+{
+  return size_;
+}
+
+data_type_t value::type() const
+{
+  return type_;
+}
+
+bool value::is_integer() const
+{
+  return type_ >= data_type_t::type_char && type_ <= data_type_t::type_unsigned_long_long;
+}
+
+bool value::is_floating_point() const
+{
+  return type_ == data_type_t::type_float || type_ == data_type_t::type_double;
+}
+
+bool value::is_bool() const
+{
+  return type_ == data_type_t::type_bool;
+}
+
+bool value::is_string() const
+{
+  return type_ == data_type_t::type_text;
+}
+
+bool value::is_varchar() const
+{
+  return type_ == data_type_t::type_varchar || type_ == data_type_t::type_char_pointer;
+}
+
+bool value::is_blob() const
+{
+  return type_ == data_type_t::type_blob;
+}
+
+bool value::is_null() const
+{
+  return type_ == data_type_t::type_null;
+}
+
+bool value::is_unknown() const
+{
+  return type_ == data_type_t::type_unknown;
+}
+
+}
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 4f9cec2..7d3608e 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -40,7 +40,8 @@ add_executable(tests
   models/author.hpp
   models/book.hpp
   FieldTest.cpp
-  models/recipe.hpp)
+  models/recipe.hpp
+  ValueTest.cpp)
 
 target_link_libraries(tests PRIVATE
   Catch2::Catch2WithMain
diff --git a/test/ColumnDefinitionGeneratorTest.cpp b/test/ColumnDefinitionGeneratorTest.cpp
index 77aa88d..d8fd9f3 100644
--- a/test/ColumnDefinitionGeneratorTest.cpp
+++ b/test/ColumnDefinitionGeneratorTest.cpp
@@ -9,7 +9,7 @@
 using namespace matador::sql;
 using namespace matador::utils;
 
-TEST_CASE("Generate columns from object", "[column generator]") {
+TEST_CASE("Generate column definitions from object", "[column][definition][generator]") {
   schema repo("main");
 
   auto columns = column_definition_generator::generate<matador::test::product>(repo);
diff --git a/test/EntityQueryBuilderTest.cpp b/test/EntityQueryBuilderTest.cpp
index eedde0c..de1998d 100644
--- a/test/EntityQueryBuilderTest.cpp
+++ b/test/EntityQueryBuilderTest.cpp
@@ -17,9 +17,9 @@ TEST_CASE("Create sql query data for entity with eager belongs to", "[query][ent
   scm.attach<author>("authors");
   scm.attach<book>("books");
 
-  entity_query_builder eqb(17, scm);
+  entity_query_builder eqb(scm);
 
-  auto data = eqb.build<book>();
+  auto data = eqb.build<book>(17);
 
   REQUIRE(data.has_value());
   REQUIRE(data->root_table_name == "books");
@@ -41,7 +41,7 @@ TEST_CASE("Create sql query data for entity with eager belongs to", "[query][ent
   }
 
   std::vector<std::pair<std::string, std::string>> expected_join_data {
-    { "books", "books.author_id = authors.id"}
+    { "books", R"("books"."author_id" = "authors"."id")"}
   };
 
   query_context qc;
@@ -54,7 +54,7 @@ TEST_CASE("Create sql query data for entity with eager belongs to", "[query][ent
 
   REQUIRE(data->where_clause);
   auto cond = data->where_clause->evaluate(db.dialect(), qc);
-  REQUIRE(cond == "books.id = 17");
+  REQUIRE(cond == R"("books"."id" = 17)");
 
   auto q = db.query(scm)
     .select(data->columns)
@@ -77,9 +77,9 @@ TEST_CASE("Create sql query data for entity with eager has many belongs to", "[q
   scm.attach<order_details>("order_details");
   scm.attach<order>("orders");
 
-  entity_query_builder eqb(17, scm);
+  entity_query_builder eqb(scm);
 
-  auto data = eqb.build<order>();
+  auto data = eqb.build<order>(17);
 
   REQUIRE(data.has_value());
   REQUIRE(data->root_table_name == "orders");
@@ -107,7 +107,7 @@ TEST_CASE("Create sql query data for entity with eager has many belongs to", "[q
   }
 
   std::vector<std::pair<std::string, std::string>> expected_join_data {
-    { "orders", "orders.order_id = order_details.order_id"}
+    { "orders", R"("orders"."order_id" = "order_details"."order_id")"}
   };
 
   query_context qc;
@@ -120,7 +120,7 @@ TEST_CASE("Create sql query data for entity with eager has many belongs to", "[q
 
   REQUIRE(data->where_clause);
   auto cond = data->where_clause->evaluate(db.dialect(), qc);
-  REQUIRE(cond == "orders.order_id = 17");
+  REQUIRE(cond == R"("orders"."order_id" = 17)");
 }
 
 TEST_CASE("Create sql query data for entity with eager many to many", "[query][entity][builder]") {
@@ -131,9 +131,9 @@ TEST_CASE("Create sql query data for entity with eager many to many", "[query][e
   scm.attach<ingredient>("ingredients");
   scm.attach<recipe_ingredient>("recipe_ingredients");
 
-  entity_query_builder eqb(17, scm);
+  entity_query_builder eqb(scm);
 
-  auto data = eqb.build<ingredient>();
+  auto data = eqb.build<ingredient>(17);
 
   REQUIRE(data.has_value());
   REQUIRE(data->root_table_name == "ingredients");
@@ -150,8 +150,8 @@ TEST_CASE("Create sql query data for entity with eager many to many", "[query][e
   }
 
   std::vector<std::pair<std::string, std::string>> expected_join_data {
-    { "ingredients", "ingredients.id = recipe_ingredients.ingredient_id"},
-    { "recipes", "recipes.id = recipe_ingredients.recipe_id"}
+    { "ingredients", R"("ingredients"."id" = "recipe_ingredients"."ingredient_id")"},
+    { "recipes", R"("recipes"."id" = "recipe_ingredients"."recipe_id")"}
   };
 
   query_context qc;
@@ -164,5 +164,5 @@ TEST_CASE("Create sql query data for entity with eager many to many", "[query][e
 
   REQUIRE(data->where_clause);
   auto cond = data->where_clause->evaluate(db.dialect(), qc);
-  REQUIRE(cond == "ingredients.id = 17");
+  REQUIRE(cond == R"("ingredients"."id" = 17)");
 }
\ No newline at end of file
diff --git a/test/FieldTest.cpp b/test/FieldTest.cpp
index b645d53..bb0b4bb 100644
--- a/test/FieldTest.cpp
+++ b/test/FieldTest.cpp
@@ -9,8 +9,8 @@ TEST_CASE("Field test", "[field]") {
 
   REQUIRE(f.name() == "name");
   REQUIRE(f.index() == -1);
-  REQUIRE(f.is_unknown());
-  REQUIRE(!f.is_null());
+  REQUIRE(!f.is_unknown());
+  REQUIRE(f.is_null());
   REQUIRE(!f.is_integer());
   REQUIRE(!f.is_floating_point());
   REQUIRE(!f.is_blob());
diff --git a/test/ValueTest.cpp b/test/ValueTest.cpp
new file mode 100644
index 0000000..48da82f
--- /dev/null
+++ b/test/ValueTest.cpp
@@ -0,0 +1,70 @@
+#include <catch2/catch_test_macros.hpp>
+
+#include "matador/sql/value.hpp"
+#include "matador/utils/types.hpp"
+
+using namespace matador::sql;
+
+TEST_CASE("Test value class", "[value]") {
+  value v;
+
+  REQUIRE(v.is_unknown());
+  REQUIRE(v.type() == data_type_t::type_unknown);
+  REQUIRE(v.size() == 0);
+
+  v = 7;
+
+  REQUIRE(v.is_integer());
+  REQUIRE(v.type() == data_type_t::type_int);
+  REQUIRE(v.size() == 0);
+  REQUIRE(v.as<int>() == 7);
+  REQUIRE(v.as<long>() == 7);
+
+  v = "test";
+
+  REQUIRE(v.is_varchar());
+  REQUIRE(v.type() == data_type_t::type_char_pointer);
+  REQUIRE(v.size() == 4);
+
+  v = std::string{"hello"};
+
+  REQUIRE(v.is_varchar());
+  REQUIRE(v.type() == data_type_t::type_varchar);
+  REQUIRE(v.size() == 5);
+
+  v = 4.5;
+
+  REQUIRE(v.is_floating_point());
+  REQUIRE(v.type() == data_type_t::type_double);
+  REQUIRE(v.size() == 0);
+
+  v = 6.7f;
+
+  REQUIRE(v.is_floating_point());
+  REQUIRE(v.type() == data_type_t::type_float);
+  REQUIRE(v.size() == 0);
+
+  v = std::string();
+
+  REQUIRE(v.is_string());
+  REQUIRE(v.type() == data_type_t::type_text);
+  REQUIRE(v.size() == 0);
+
+  v = true;
+
+  REQUIRE(v.is_bool());
+  REQUIRE(v.type() == data_type_t::type_bool);
+  REQUIRE(v.size() == 0);
+
+  v = nullptr;
+
+  REQUIRE(v.is_null());
+  REQUIRE(v.type() == data_type_t::type_null);
+  REQUIRE(v.size() == 0);
+
+  v = matador::utils::blob{ 1, 2, 3, 4 };
+
+  REQUIRE(v.is_blob());
+  REQUIRE(v.type() == data_type_t::type_blob);
+  REQUIRE(v.size() == 4);
+}
\ No newline at end of file