From ffb804d77644ff1a127ecd28959737e527976297 Mon Sep 17 00:00:00 2001
From: bergmann <info@bergmann89.de>
Date: Sat, 29 Jun 2019 11:23:59 +0200
Subject: [PATCH] * Refactored modifier implementation

---
 include/cpphibernate.h                        |   1 +
 include/cpphibernate/modifier.h               |  18 ++
 include/cpphibernate/modifier/limit.h         |  43 ++--
 include/cpphibernate/modifier/limit.inl       |  50 ++++
 include/cpphibernate/modifier/modifier.h      |  33 +--
 include/cpphibernate/modifier/modifier.inl    |  25 ++
 include/cpphibernate/modifier/modifiers.h     |  69 ++---
 include/cpphibernate/modifier/modifiers.inl   |  63 +++++
 include/cpphibernate/modifier/offset.h        |  43 ++--
 include/cpphibernate/modifier/offset.inl      |  50 ++++
 include/cpphibernate/modifier/order_by.h      | 173 ++-----------
 include/cpphibernate/modifier/order_by.inl    |  54 ++++
 .../modifier/order_by/ascending.h             |  38 +++
 .../modifier/order_by/ascending.inl           |  49 ++++
 .../modifier/order_by/descending.h            |  38 +++
 .../modifier/order_by/descending.inl          |  47 ++++
 .../modifier/order_by/order_direction.h       |  22 ++
 .../modifier/order_by/order_direction.inl     |  37 +++
 include/cpphibernate/modifier/where.h         |  38 ++-
 include/cpphibernate/modifier/where.inl       |  59 +++++
 include/cpphibernate/modifier/where/clauses.h |   7 -
 .../cpphibernate/modifier/where/clauses/and.h |  60 -----
 .../modifier/where/clauses/clause.h           |  31 ---
 .../modifier/where/clauses/equal.h            |  64 -----
 .../cpphibernate/modifier/where/clauses/not.h |  60 -----
 .../cpphibernate/modifier/where/clauses/or.h  |  60 -----
 .../cpphibernate/modifier/where/conjunction.h |  59 +++++
 .../modifier/where/conjunction.inl            |  69 +++++
 .../cpphibernate/modifier/where/disjunction.h |  59 +++++
 .../modifier/where/disjunction.inl            |  69 +++++
 include/cpphibernate/modifier/where/equal.h   |  38 +++
 include/cpphibernate/modifier/where/equal.inl |  64 +++++
 .../cpphibernate/modifier/where/negation.h    |  59 +++++
 .../cpphibernate/modifier/where/negation.inl  |  67 +++++
 include/cpphibernate/modifier/where/where.h   |  60 -----
 .../modifier/where/where_clause.h             |  22 ++
 .../modifier/where/where_clause.inl           |  25 ++
 include/cpphibernate/schema/attributes.inl    |   2 +-
 include/cpphibernate/schema/fields.inl        |   2 +-
 include/cpphibernate/schema/tables.inl        |   2 +-
 test/cpphibernate/cpphibernate_tests.cpp      |  25 +-
 test/test_schema.h                            | 236 ------------------
 42 files changed, 1233 insertions(+), 857 deletions(-)
 create mode 100644 include/cpphibernate/modifier.h
 create mode 100644 include/cpphibernate/modifier/limit.inl
 create mode 100644 include/cpphibernate/modifier/modifier.inl
 create mode 100644 include/cpphibernate/modifier/modifiers.inl
 create mode 100644 include/cpphibernate/modifier/offset.inl
 create mode 100644 include/cpphibernate/modifier/order_by.inl
 create mode 100644 include/cpphibernate/modifier/order_by/ascending.h
 create mode 100644 include/cpphibernate/modifier/order_by/ascending.inl
 create mode 100644 include/cpphibernate/modifier/order_by/descending.h
 create mode 100644 include/cpphibernate/modifier/order_by/descending.inl
 create mode 100644 include/cpphibernate/modifier/order_by/order_direction.h
 create mode 100644 include/cpphibernate/modifier/order_by/order_direction.inl
 create mode 100644 include/cpphibernate/modifier/where.inl
 delete mode 100644 include/cpphibernate/modifier/where/clauses.h
 delete mode 100644 include/cpphibernate/modifier/where/clauses/and.h
 delete mode 100644 include/cpphibernate/modifier/where/clauses/clause.h
 delete mode 100644 include/cpphibernate/modifier/where/clauses/equal.h
 delete mode 100644 include/cpphibernate/modifier/where/clauses/not.h
 delete mode 100644 include/cpphibernate/modifier/where/clauses/or.h
 create mode 100644 include/cpphibernate/modifier/where/conjunction.h
 create mode 100644 include/cpphibernate/modifier/where/conjunction.inl
 create mode 100644 include/cpphibernate/modifier/where/disjunction.h
 create mode 100644 include/cpphibernate/modifier/where/disjunction.inl
 create mode 100644 include/cpphibernate/modifier/where/equal.h
 create mode 100644 include/cpphibernate/modifier/where/equal.inl
 create mode 100644 include/cpphibernate/modifier/where/negation.h
 create mode 100644 include/cpphibernate/modifier/where/negation.inl
 delete mode 100644 include/cpphibernate/modifier/where/where.h
 create mode 100644 include/cpphibernate/modifier/where/where_clause.h
 create mode 100644 include/cpphibernate/modifier/where/where_clause.inl
 delete mode 100644 test/test_schema.h

diff --git a/include/cpphibernate.h b/include/cpphibernate.h
index dc4dd33..3dbc55a 100644
--- a/include/cpphibernate.h
+++ b/include/cpphibernate.h
@@ -1,5 +1,6 @@
 #pragma once
 
 #include "cpphibernate/misc.h"
+#include "cpphibernate/modifier.h"
 #include "cpphibernate/schema.h"
 #include "cpphibernate/types.h"
diff --git a/include/cpphibernate/modifier.h b/include/cpphibernate/modifier.h
new file mode 100644
index 0000000..2d487c6
--- /dev/null
+++ b/include/cpphibernate/modifier.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "modifier/modifier.h"
+#include "modifier/modifiers.h"
+
+#include "modifier/limit.h"
+#include "modifier/offset.h"
+
+#include "modifier/order_by.h"
+#include "modifier/order_by/ascending.h"
+#include "modifier/order_by/descending.h"
+
+#include "modifier/where.h"
+#include "modifier/where/where_clause.h"
+#include "modifier/where/equal.h"
+#include "modifier/where/negation.h"
+#include "modifier/where/conjunction.h"
+#include "modifier/where/disjunction.h"
diff --git a/include/cpphibernate/modifier/limit.h b/include/cpphibernate/modifier/limit.h
index 39c3256..80f8b21 100644
--- a/include/cpphibernate/modifier/limit.h
+++ b/include/cpphibernate/modifier/limit.h
@@ -1,39 +1,38 @@
 #pragma once
 
-#include <cpphibernate/misc.h>
 #include <cpphibernate/config.h>
-#include <cpphibernate/modifier/modifier.h>
 
-beg_namespace_cpphibernate_modifier
+namespace cpphibernate
 {
 
     namespace __impl
     {
 
-        /* limit_t */
-
-        template<typename T_value>
-        struct limit_t
-            : public modifier_t
-        {
-            using value_type = T_value;
-
-            value_type value;
-        };
+        /**
+         * @brief Helper class to build limit objects.
+         */
+        template<typename X, typename = void>
+        struct limit_builder;
 
     }
 
-    /* meta */
-
+    /**
+     * @brief Evaluates to true_t if the passed type is a limit modifier, false_t otherwise.
+     */
     template<typename T>
-    struct is_limit_modifier
-        : public mp::is_specialization_of<T, __impl::limit_t>
-        { };
+    struct is_limit_modifier;
 
-    /* make */
+    /**
+     * @brief Is true if the passed type is a limit modifier, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_limit_modifier_v = is_limit_modifier<T>::value;
 
-    template<size_t T_value>
-    constexpr decltype(auto) limit = __impl::limit_t<hana::size_t<T_value>> { };
+    /**
+     * @brief Predicate to create new limit objects.
+     */
+    constexpr decltype(auto) limit = mp::generic_predicate<__impl::limit_builder> { };
 
 }
-end_namespace_cpphibernate_modifier
\ No newline at end of file
+
+#include "limit.inl"
diff --git a/include/cpphibernate/modifier/limit.inl b/include/cpphibernate/modifier/limit.inl
new file mode 100644
index 0000000..b54be4b
--- /dev/null
+++ b/include/cpphibernate/modifier/limit.inl
@@ -0,0 +1,50 @@
+#pragma once
+
+#include "limit.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* limit_t */
+
+        template<typename T_value>
+        struct limit_t
+            : public mp::size_t<T_value::value>
+            , public tag_modifier
+            , public tag_equality_comparable<tag_modifier>
+            { };
+
+        /* limit_builder */
+
+        template<typename X, typename>
+        struct limit_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&...)
+                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for limit(...)!"); }
+        };
+
+        template<typename T>
+        struct limit_builder<
+            mp::list<T>,
+            mp::enable_if_t<
+                    mp::is_valid_v<decltype(T::value)>
+                &&  mp::is_integral_v<mp::decay_t<decltype(T::value)>>>>
+        {
+            static constexpr decltype(auto) apply(T&&)
+                { return limit_t<T> { }; }
+        };
+
+    }
+
+    /* is_limit_modifier */
+
+    template<typename T>
+    struct is_limit_modifier
+        : public mp::is_specialization_of<T, __impl::limit_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/modifier.h b/include/cpphibernate/modifier/modifier.h
index 5e24e90..7a066f8 100644
--- a/include/cpphibernate/modifier/modifier.h
+++ b/include/cpphibernate/modifier/modifier.h
@@ -2,30 +2,21 @@
 
 #include <cpphibernate/config.h>
 
-beg_namespace_cpphibernate_modifier
+namespace cpphibernate
 {
 
-    namespace __impl
-    {
-
-        /* modifier_t */
-
-        struct modifier_t
-            { };
-
-    }
-
-    /* meta */
-
+    /**
+     * @brief Evaluates to true_t if the passed type is a modifier, false_t otherwise.
+     */
     template<typename T>
-    struct is_modifier
-        : public mp::is_base_of<__impl::modifier_t, T>
-        { };
+    struct is_modifier;
 
-    template<typename... T>
-    struct all_are_modifiers
-        : public mp::all_true<is_modifier<T>::value...>
-        { };
+    /**
+     * @brief Is true if the passed type is a modifier, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_modifier_v = is_modifier<T>::value;
 
 }
-end_namespace_cpphibernate_modifier
\ No newline at end of file
+
+#include "modifier.inl"
diff --git a/include/cpphibernate/modifier/modifier.inl b/include/cpphibernate/modifier/modifier.inl
new file mode 100644
index 0000000..cf3019e
--- /dev/null
+++ b/include/cpphibernate/modifier/modifier.inl
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "modifier.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* tag_modifier */
+
+        struct tag_modifier
+            { };
+
+    }
+
+    /* is_modifier */
+
+    template<typename T>
+    struct is_modifier
+        : public mp::is_base_of<__impl::tag_modifier, T>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/modifiers.h b/include/cpphibernate/modifier/modifiers.h
index f1b5782..0a82c4c 100644
--- a/include/cpphibernate/modifier/modifiers.h
+++ b/include/cpphibernate/modifier/modifiers.h
@@ -1,65 +1,38 @@
 #pragma once
 
-#include <cpphibernate/misc.h>
 #include <cpphibernate/config.h>
-#include <cpphibernate/modifier/modifier.h>
 
-beg_namespace_cpphibernate_modifier
-{
+namespace cpphibernate {
+namespace schema {
 
     namespace __impl
     {
 
-        /* is_modifiers_impl */
-
+        /**
+         * @brief Helper type to build modifiers.
+         */
         template<typename T, typename = void>
-        struct is_modifiers_impl
-            : mp::c_false_t
-            { };
-
-        template<typename... T>
-        struct is_modifiers_impl<hana::basic_tuple<T...>, mp::enable_if<all_are_modifiers<T...>>>
-            : mp::c_true_t
-            { };
+        struct modifiers_builder;
 
     }
 
-    /* meta */
-
+    /**
+     * @brief Evaluates to true_t if the passed type is a modifiers type.
+     */
     template<typename T>
-    struct is_modifiers
-        : public __impl::is_modifiers_impl<T>
-        { };
-
-    /* operations */
-
-    namespace __impl
-    {
-
-        /* make_modifiers_impl */
-
-        template<typename T, typename = void>
-        struct make_modifiers_impl
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&...)
-                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for hibernate::schema::modifier::make(...)!"); }
-        };
+    struct is_modifiers;
 
-        template<typename... T>
-        struct make_modifiers_impl<
-            mp::list<T...>,
-            mp::enable_if_c<
-                all_are_modifiers<mp::decay_t<T>...>::value>>
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { return hana::make_basic_tuple(std::forward<T_args>(args)...); }
-        };
+    /**
+     * @brief Is true if the passed type is an modifiers type, false otherwise.
+     */
+    template<typename T>
+    constexpr bool is_modifiers_v = is_modifiers<T>::value;
 
-    }
+    /**
+     * @brief Predicate to create an modifiers object from the passed modifiers.
+     */
+    constexpr decltype(auto) make_modifiers = mp::generic_predicate<__impl::modifiers_builder> { };
 
-    constexpr decltype(auto) make_list = misc::make_generic_predicate<__impl::make_modifiers_impl> { };
+} }
 
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
+#include "modifiers.inl"
diff --git a/include/cpphibernate/modifier/modifiers.inl b/include/cpphibernate/modifier/modifiers.inl
new file mode 100644
index 0000000..8044483
--- /dev/null
+++ b/include/cpphibernate/modifier/modifiers.inl
@@ -0,0 +1,63 @@
+#pragma once
+
+#include "modifier.h"
+#include "modifiers.h"
+
+namespace cpphibernate {
+namespace schema {
+
+    namespace __impl
+    {
+
+        /* modifiers_t */
+
+        template<typename... T_modifiers>
+        using modifiers_t = hana::basic_tuple<T_modifiers...>;
+
+        /* modifiers_builder */
+
+        template<typename T, typename>
+        struct modifiers_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&...)
+                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for make_modifiers(...)!"); }
+        };
+
+        template<typename... T_args>
+        struct modifiers_builder<
+            mp::list<T_args...>,
+            mp::enable_if_t<
+                mp::is_true_v<is_modifier_v<mp::decay_t<T_args>>...>>>
+        {
+            static constexpr decltype(auto) apply(T_args&&... args)
+            {
+                using modifiers_type = modifiers_t<T_args...>;
+                return modifiers_type(std::forward<T_args>(args)...);
+            }
+        };
+
+        /* is_modifiers_impl */
+
+        template<typename T, typename = void>
+        struct is_modifiers_impl
+            : mp::false_t
+            { };
+
+        template<typename... T>
+        struct is_modifiers_impl<
+            modifiers_t<T...>,
+            mp::enable_if_t<mp::is_true_v<is_modifier_v<mp::decay_t<T>>...>>>
+            : mp::true_t
+            { };
+
+    }
+
+    /* is_modifiers */
+
+    template<typename T>
+    struct is_modifiers
+        : public __impl::is_modifiers_impl<T>
+        { };
+
+} }
diff --git a/include/cpphibernate/modifier/offset.h b/include/cpphibernate/modifier/offset.h
index 20bbcec..cbad170 100644
--- a/include/cpphibernate/modifier/offset.h
+++ b/include/cpphibernate/modifier/offset.h
@@ -1,39 +1,38 @@
 #pragma once
 
-#include <cpphibernate/misc.h>
 #include <cpphibernate/config.h>
-#include <cpphibernate/modifier/modifier.h>
 
-beg_namespace_cpphibernate_modifier
+namespace cpphibernate
 {
 
     namespace __impl
     {
 
-        /* offset_t */
-
-        template<typename T_value>
-        struct offset_t
-            : public modifier_t
-        {
-            using value_type = T_value;
-
-            value_type value;
-        };
+        /**
+         * @brief Helper class to build offset objects.
+         */
+        template<typename X, typename = void>
+        struct offset_builder;
 
     }
 
-    /* meta */
-
+    /**
+     * @brief Evaluates to true_t if the passed type is a offset modifier, false_t otherwise.
+     */
     template<typename T>
-    struct is_offset
-        : public mp::is_specialization_of<T, __impl::offset_t>
-        { };
+    struct is_offset_modifier;
 
-    /* make */
+    /**
+     * @brief Is true if the passed type is a offset modifier, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_offset_modifier_v = is_offset_modifier<T>::value;
 
-    template<size_t T_value>
-    constexpr decltype(auto) offset = __impl::offset_t<hana::size_t<T_value>> { };
+    /**
+     * @brief Predicate to create new offset objects.
+     */
+    constexpr decltype(auto) offset = mp::generic_predicate<__impl::offset_builder> { };
 
 }
-end_namespace_cpphibernate_modifier
\ No newline at end of file
+
+#include "offset.inl"
diff --git a/include/cpphibernate/modifier/offset.inl b/include/cpphibernate/modifier/offset.inl
new file mode 100644
index 0000000..2e3f7ff
--- /dev/null
+++ b/include/cpphibernate/modifier/offset.inl
@@ -0,0 +1,50 @@
+#pragma once
+
+#include "offset.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* offset_t */
+
+        template<typename T_value>
+        struct offset_t
+            : public mp::size_t<T_value::value>
+            , public tag_modifier
+            , public tag_equality_comparable<tag_modifier>
+            { };
+
+        /* offset_builder */
+
+        template<typename X, typename>
+        struct offset_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&...)
+                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for offset(...)!"); }
+        };
+
+        template<typename T>
+        struct offset_builder<
+            mp::list<T>,
+            mp::enable_if_t<
+                    mp::is_valid_v<decltype(T::value)>
+                &&  mp::is_integral_v<mp::decay_t<decltype(T::value)>>>>
+        {
+            static constexpr decltype(auto) apply(T&&)
+                { return offset_t<T> { }; }
+        };
+
+    }
+
+    /* is_offset_modifier */
+
+    template<typename T>
+    struct is_offset_modifier
+        : public mp::is_specialization_of<T, __impl::offset_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/order_by.h b/include/cpphibernate/modifier/order_by.h
index 515c0b9..c4f580a 100644
--- a/include/cpphibernate/modifier/order_by.h
+++ b/include/cpphibernate/modifier/order_by.h
@@ -1,171 +1,38 @@
 #pragma once
 
-#include <cpphibernate/misc.h>
 #include <cpphibernate/config.h>
-#include <cpphibernate/modifier/modifier.h>
 
-beg_namespace_cpphibernate_modifier
+namespace cpphibernate
 {
 
     namespace __impl
     {
 
-        /* order_direction_tag_t */
-
-        struct order_direction_tag_t
-            { };
-
-        /* order_direction_t */
-
-        template<typename T_field>
-        struct order_direction_t
-            : public order_direction_tag_t
-        {
-            using field_type            = T_field;
-            using wrapped_field_type    = hana::type<mp::decay_t<field_type>>;
-
-            wrapped_field_type wrapped_field;
-        };
+        /**
+         * @brief Helper class to build order_by objects.
+         */
+        template<typename X, typename = void>
+        struct order_by_builder;
 
     }
 
-    /* meta */
-
+    /**
+     * @brief Evaluates to true_t if the passed type is a offset modifier, false_t otherwise.
+     */
     template<typename T>
-    struct is_order_direction
-        : public mp::is_base_of<__impl::order_direction_tag_t, T>
-        { };
-
-    template<typename... T>
-    struct all_are_order_directions
-        : public mp::all_true<is_order_direction<T>::value...>
-        { };
-
-    namespace __impl
-    {
-
-        /* order_ascending_t */
-
-        template<typename T_field>
-        struct order_ascending_t
-            : public order_direction_t<T_field>
-            { };
-
-        /* order_descending_t */
-
-        template<typename T_field>
-        struct order_descending_t
-            : public order_direction_t<T_field>
-            { };
-
-        /* order_by_t */
-
-        template<typename... T_fields>
-        struct order_by_t
-            : public modifier_t
-        {
-            using fields_type = hana::basic_tuple<T_fields...>;
-
-            fields_type fields;
-        };
-
-    }
-
-    /* meta */
+    struct is_order_by_modifier;
 
+    /**
+     * @brief Is true if the passed type is a offset modifier, false otherwise.
+     */
     template<typename T>
-    struct is_order_by
-        : public mp::is_specialization_of<T, __impl::order_by_t>
-        { };
+    constexpr decltype(auto) is_order_by_modifier_v = is_order_by_modifier<T>::value;
 
-    template<typename T>
-    struct is_ascending
-        : public mp::is_specialization_of<T, __impl::order_ascending_t>
-        { };
-
-    template<typename T>
-    struct is_descending
-        : public mp::is_specialization_of<T, __impl::order_descending_t>
-        { };
-
-    namespace __impl
-    {
-
-        /* ascending_builder */
-
-        template<typename X, typename = void>
-        struct ascending_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::ascending(...)!"); }
-        };
-
-        template<typename T_field>
-        struct ascending_builder<
-            mp::list<T_field>,
-            mp::enable_if<schema::is_field<mp::decay_t<T_field>>>>
-        {
-            static constexpr decltype(auto) apply(T_field&&)
-            {
-                using field_type     = mp::decay_t<T_field>;
-                using ascending_type = order_ascending_t<field_type>;
-                return ascending_type { };
-            }
-        };
-
-        /* descending_builder */
-
-        template<typename X, typename = void>
-        struct descending_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::descending(...)!"); }
-        };
-
-        template<typename T_field>
-        struct descending_builder<
-            mp::list<T_field>,
-            mp::enable_if<schema::is_field<mp::decay_t<T_field>>>>
-        {
-            static constexpr decltype(auto) apply(T_field&&)
-            {
-                using field_type      = mp::decay_t<T_field>;
-                using descending_type = order_descending_t<field_type>;
-                return descending_type { };
-            }
-        };
-
-        /* order_by_builder */
-
-        template<typename X, typename = void>
-        struct order_by_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::order_by(...)!"); }
-        };
-
-        template<typename... T_order_directions>
-        struct order_by_builder<
-            mp::list<T_order_directions...>,
-            mp::enable_if<all_are_order_directions<mp::decay_t<T_order_directions>...>>>
-        {
-            static constexpr decltype(auto) apply(T_order_directions&&...)
-            {
-                using order_by_type = order_by_t<mp::decay_t<T_order_directions>...>;
-                return order_by_type { };
-            }
-        };
-
-    }
-
-    /* make */
-
-    constexpr decltype(auto) ascending  = misc::make_generic_predicate<__impl::ascending_builder>  { };
-    constexpr decltype(auto) descending = misc::make_generic_predicate<__impl::descending_builder> { };
-    constexpr decltype(auto) order_by   = misc::make_generic_predicate<__impl::order_by_builder>   { };
+    /**
+     * @brief Predicate to create new offset objects.
+     */
+    constexpr decltype(auto) order_by = mp::generic_predicate<__impl::order_by_builder> { };
 
 }
-end_namespace_cpphibernate_modifier
\ No newline at end of file
+
+#include "order_by.inl"
diff --git a/include/cpphibernate/modifier/order_by.inl b/include/cpphibernate/modifier/order_by.inl
new file mode 100644
index 0000000..f1fdd86
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by.inl
@@ -0,0 +1,54 @@
+#pragma once
+
+#include "order_by.h"
+#include "order_by/order_direction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* order_by_t */
+
+        template<typename... T_order_directions>
+        struct order_by_t
+            : public tag_modifier
+        {
+            using order_directions_type = hana::basic_tuple<T_order_directions...>;
+
+            order_directions_type order_directions;
+        };
+
+        /* order_by_builder */
+
+        template<typename X, typename>
+        struct order_by_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&...)
+                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for order_by(...)!"); }
+        };
+
+        template<typename... T_order_directions>
+        struct order_by_builder<
+            mp::list<T_order_directions...>,
+            mp::enable_if_t<mp::is_true_v<is_order_direction_v<mp::decay_t<T_order_directions>>...>>>
+        {
+            static constexpr decltype(auto) apply(T_order_directions&&...)
+            {
+                using order_by_type = order_by_t<mp::decay_t<T_order_directions>...>;
+                return order_by_type { };
+            }
+        };
+
+    }
+
+    /* is_order_by_modifier */
+
+    template<typename T>
+    struct is_order_by_modifier
+        : public mp::is_specialization_of<T, __impl::order_by_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/order_by/ascending.h b/include/cpphibernate/modifier/order_by/ascending.h
new file mode 100644
index 0000000..3fa1f82
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/ascending.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build ascending objects.
+         */
+        template<typename X, typename = void>
+        struct ascending_builder;
+
+    }
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a ascending order, false_t otherwise.
+     */
+    template<typename T>
+    struct is_ascending;
+
+    /**
+     * @brief Is true if the passed type is a ascending order, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_ascending_v = is_ascending<T>::value;
+
+    /**
+     * @brief Predicate to create new ascending order objects.
+     */
+    constexpr decltype(auto) ascending = mp::generic_predicate<__impl::ascending_builder> { };
+
+}
+
+#include "ascending.inl"
diff --git a/include/cpphibernate/modifier/order_by/ascending.inl b/include/cpphibernate/modifier/order_by/ascending.inl
new file mode 100644
index 0000000..434a266
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/ascending.inl
@@ -0,0 +1,49 @@
+#pragma once
+
+#include <cpphibernate/schema/field.h>
+
+#include "ascending.h"
+#include "order_direction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* ascending_t */
+
+        template<typename T_field>
+        struct ascending_t
+            : public order_direction_t<T_field>
+            { };
+
+        /* ascending_builder */
+
+        template<typename X, typename>
+        struct ascending_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::ascending(...)!"); }
+        };
+
+        template<typename T_field>
+        struct ascending_builder<
+            mp::list<T_field>,
+            mp::enable_if_t<schema::is_field_v<mp::decay_t<T_field>>>>
+        {
+            static constexpr decltype(auto) apply(T_field&&)
+                { return ascending_t<T_field> { }; }
+        };
+
+    }
+
+    /* is_ascending */
+
+    template<typename T>
+    struct is_ascending
+        : public mp::is_specialization_of<T, __impl::ascending_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/order_by/descending.h b/include/cpphibernate/modifier/order_by/descending.h
new file mode 100644
index 0000000..e274edd
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/descending.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build descending objects.
+         */
+        template<typename X, typename = void>
+        struct descending_builder;
+
+    }
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a descending order, false_t otherwise.
+     */
+    template<typename T>
+    struct is_descending;
+
+    /**
+     * @brief Is true if the passed type is a descending order, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_descending_v = is_descending<T>::value;
+
+    /**
+     * @brief Predicate to create new descending order objects.
+     */
+    constexpr decltype(auto) descending = mp::generic_predicate<__impl::descending_builder> { };
+
+}
+
+#include "descending.inl"
diff --git a/include/cpphibernate/modifier/order_by/descending.inl b/include/cpphibernate/modifier/order_by/descending.inl
new file mode 100644
index 0000000..78fddf8
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/descending.inl
@@ -0,0 +1,47 @@
+#pragma once
+
+#include "descending.h"
+#include "order_direction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* descending_t */
+
+        template<typename T_field>
+        struct descending_t
+            : public order_direction_t<T_field>
+            { };
+
+        /* descending_builder */
+
+        template<typename X, typename>
+        struct descending_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::descending(...)!"); }
+        };
+
+        template<typename T_field>
+        struct descending_builder<
+            mp::list<T_field>,
+            mp::enable_if_t<schema::is_field_v<mp::decay_t<T_field>>>>
+        {
+            static constexpr decltype(auto) apply(T_field&&)
+                { return descending_t<T_field> { }; }
+        };
+
+    }
+
+    /* is_descending */
+
+    template<typename T>
+    struct is_descending
+        : public mp::is_specialization_of<T, __impl::descending_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/order_by/order_direction.h b/include/cpphibernate/modifier/order_by/order_direction.h
new file mode 100644
index 0000000..2ce643b
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/order_direction.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a order_direction, false_t otherwise.
+     */
+    template<typename T>
+    struct is_order_direction;
+
+    /**
+     * @brief Is true if the passed type is a order_direction, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_order_direction_v = is_order_direction<T>::value;
+
+}
+
+#include "order_direction.inl"
diff --git a/include/cpphibernate/modifier/order_by/order_direction.inl b/include/cpphibernate/modifier/order_by/order_direction.inl
new file mode 100644
index 0000000..58b24e2
--- /dev/null
+++ b/include/cpphibernate/modifier/order_by/order_direction.inl
@@ -0,0 +1,37 @@
+#pragma once
+
+#include "order_direction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* tag_order_direction */
+
+        struct tag_order_direction
+            { };
+
+        /* order_direction_t */
+
+        template<typename T_field>
+        struct order_direction_t
+            : public tag_order_direction
+        {
+            using field_type            = T_field;
+            using wrapped_field_type    = hana::type<mp::decay_t<field_type>>;
+
+            wrapped_field_type wrapped_field;
+        };
+
+    }
+
+    /* is_order_direction */
+
+    template<typename T>
+    struct is_order_direction
+        : public mp::is_base_of<__impl::tag_order_direction, T>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where.h b/include/cpphibernate/modifier/where.h
index e381b88..024f1a2 100644
--- a/include/cpphibernate/modifier/where.h
+++ b/include/cpphibernate/modifier/where.h
@@ -1,4 +1,38 @@
 #pragma once
 
-#include <cpphibernate/modifier/where/clauses.h>
-#include <cpphibernate/modifier/where/where.h>
\ No newline at end of file
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build where objects.
+         */
+        template<typename X, typename = void>
+        struct where_builder;
+
+    }
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a where modifier, false_t otherwise.
+     */
+    template<typename T>
+    struct is_where_modifier;
+
+    /**
+     * @brief Is true if the passed type is a where modifier, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_where_modifier_v = is_where_modifier<T>::value;
+
+    /**
+     * @brief Predicate to create new where objects.
+     */
+    constexpr decltype(auto) where = mp::generic_predicate<__impl::where_builder> { };
+
+}
+
+#include "where.inl"
diff --git a/include/cpphibernate/modifier/where.inl b/include/cpphibernate/modifier/where.inl
new file mode 100644
index 0000000..ce82757
--- /dev/null
+++ b/include/cpphibernate/modifier/where.inl
@@ -0,0 +1,59 @@
+#pragma once
+
+#include "where.h"
+#include "where/where_clause.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* where_t */
+
+        template<typename T_where_clause>
+        struct where_t
+            : public tag_modifier
+        {
+            using clause_type = T_where_clause;
+
+            clause_type clause;
+
+            constexpr where_t(clause_type&& p_clause)
+                : clause(p_clause)
+                { }
+        };
+
+        /* where_builder */
+
+        template<typename X, typename>
+        struct where_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&...)
+                { static_assert(sizeof...(T_args) == -1, "Invalid parameters for where(...)!"); }
+        };
+
+        template<typename T_where_clause>
+        struct where_builder<
+            mp::list<T_where_clause>,
+            mp::enable_if_t<mp::is_true_v<is_where_clause_v<mp::decay_t<T_where_clause>>>>>
+        {
+            static constexpr decltype(auto) apply(T_where_clause&& clause)
+            {
+                using clause_type = T_where_clause;
+                using where_type  = where_t<clause_type>;
+                return where_type(std::forward<clause_type>(clause));
+            }
+        };
+
+    }
+
+    /* is_where_modifier */
+
+    template<typename T>
+    struct is_where_modifier
+        : public mp::is_specialization_of<T, __impl::where_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where/clauses.h b/include/cpphibernate/modifier/where/clauses.h
deleted file mode 100644
index f716bce..0000000
--- a/include/cpphibernate/modifier/where/clauses.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#pragma once
-
-#include <cpphibernate/modifier/where/clauses/and.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-#include <cpphibernate/modifier/where/clauses/equal.h>
-#include <cpphibernate/modifier/where/clauses/not.h>
-#include <cpphibernate/modifier/where/clauses/or.h>
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/clauses/and.h b/include/cpphibernate/modifier/where/clauses/and.h
deleted file mode 100644
index 942fc3b..0000000
--- a/include/cpphibernate/modifier/where/clauses/and.h
+++ /dev/null
@@ -1,60 +0,0 @@
-#pragma once
-
-#include <cpphibernate/config.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_clause_and_t */
-
-        template<typename... T_clauses>
-        struct where_clause_and_t
-            : public where_clause_t
-        {
-            using clauses_type = hana::tuple<T_clauses...>;
-
-            clauses_type clauses;
-
-            constexpr where_clause_and_t(T_clauses&&... p_clauses)
-                : clauses(std::forward<T_clauses>(p_clauses)...)
-                { }
-        };
-
-        /* where_clause_and_builder */
-
-        template<typename X, typename = void>
-        struct where_clause_and_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::and(...)!"); }
-        };
-
-        template<typename... T_clauses>
-        struct where_clause_and_builder<
-            mp::list<T_clauses...>,
-            mp::enable_if<all_are_where_clauses<mp::decay_t<T_clauses>...>>>
-        {
-            static constexpr decltype(auto) apply(T_clauses&&... clauses)
-                { return where_clause_and_t<T_clauses...>(std::forward<T_clauses>(clauses)...); }
-        };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where_clause_and
-        : public mp::is_specialization_of<T, __impl::where_clause_and_t>
-        { };
-
-    /* make */
-
-    constexpr decltype(auto) and_ = misc::make_generic_predicate<__impl::where_clause_and_builder> { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/clauses/clause.h b/include/cpphibernate/modifier/where/clauses/clause.h
deleted file mode 100644
index f1ed328..0000000
--- a/include/cpphibernate/modifier/where/clauses/clause.h
+++ /dev/null
@@ -1,31 +0,0 @@
-#pragma once
-
-#include <cpphibernate/config.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_clause_t */
-
-        struct where_clause_t
-            { };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where_clause
-        : public mp::is_base_of<__impl::where_clause_t, T>
-        { };
-
-    template<typename... T>
-    struct all_are_where_clauses
-        : public mp::all_true<is_where_clause<T>::value...>
-        { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/clauses/equal.h b/include/cpphibernate/modifier/where/clauses/equal.h
deleted file mode 100644
index b994fd8..0000000
--- a/include/cpphibernate/modifier/where/clauses/equal.h
+++ /dev/null
@@ -1,64 +0,0 @@
-#pragma once
-
-#include <cpphibernate/config.h>
-#include <cpphibernate/schema/field.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_clause_equal_t */
-
-        template<typename T_field, typename T_value>
-        struct where_clause_equal_t
-            : public where_clause_t
-        {
-            using field_type = T_field;
-            using value_type = T_value;
-
-            field_type field;
-            value_type value;
-
-            constexpr where_clause_equal_t(T_field&& p_field, T_value&& p_value)
-                : field(std::forward<T_field>(p_field))
-                , value(std::forward<T_value>(p_value))
-                { }
-        };
-
-        /* where_clause_equal_builder */
-
-        template<typename X, typename = void>
-        struct where_clause_equal_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::equal(...)!"); }
-        };
-
-        template<typename T_field, typename T_value>
-        struct where_clause_equal_builder<
-            mp::list<T_field, T_value>,
-            mp::enable_if<schema::is_field<mp::decay_t<T_field>>>>
-        {
-            static constexpr decltype(auto) apply(T_field&& field, T_value&& value)
-                { return where_clause_equal_t<T_field, T_value>(std::forward<T_field>(field), std::forward<T_value>(value)); }
-        };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where_clause_equal
-        : public mp::is_specialization_of<T, __impl::where_clause_equal_t>
-        { };
-
-    /* make */
-
-    constexpr decltype(auto) equal = misc::make_generic_predicate<__impl::where_clause_equal_builder> { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/clauses/not.h b/include/cpphibernate/modifier/where/clauses/not.h
deleted file mode 100644
index e8cf36e..0000000
--- a/include/cpphibernate/modifier/where/clauses/not.h
+++ /dev/null
@@ -1,60 +0,0 @@
-#pragma once
-
-#include <cpphibernate/config.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_clause_not_t */
-
-        template<typename T_clause>
-        struct where_clause_not_t
-            : public where_clause_t
-        {
-            using clause_type = T_clause;
-
-            clause_type clause;
-
-            constexpr where_clause_not_t(T_clause&& p_clause)
-                : clause(std::forward<T_clause>(p_clause))
-                { }
-        };
-
-        /* where_clause_not_builder */
-
-        template<typename X, typename = void>
-        struct where_clause_not_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::not(...)!"); }
-        };
-
-        template<typename T_clause>
-        struct where_clause_not_builder<
-            mp::list<T_clause>,
-            mp::enable_if<is_where_clause<mp::decay_t<T_clause>>>>
-        {
-            static constexpr decltype(auto) apply(T_clause&& clause)
-                { return where_clause_not_t<T_clause>(std::forward<T_clause>(clause)); }
-        };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where_clause_not
-        : public mp::is_specialization_of<T, __impl::where_clause_not_t>
-        { };
-
-    /* make */
-
-    constexpr decltype(auto) not_ = misc::make_generic_predicate<__impl::where_clause_not_builder> { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/clauses/or.h b/include/cpphibernate/modifier/where/clauses/or.h
deleted file mode 100644
index 79dd497..0000000
--- a/include/cpphibernate/modifier/where/clauses/or.h
+++ /dev/null
@@ -1,60 +0,0 @@
-#pragma once
-
-#include <cpphibernate/config.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_clause_or_t */
-
-        template<typename... T_clauses>
-        struct where_clause_or_t
-            : public where_clause_t
-        {
-            using clauses_type = hana::tuple<T_clauses...>;
-
-            clauses_type clauses;
-
-            constexpr where_clause_or_t(T_clauses&&... p_clauses)
-                : clauses(std::forward<T_clauses>(p_clauses)...)
-                { }
-        };
-
-        /* where_clause_or_builder */
-
-        template<typename X, typename = void>
-        struct where_clause_or_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::or(...)!"); }
-        };
-
-        template<typename... T_clauses>
-        struct where_clause_or_builder<
-            mp::list<T_clauses...>,
-            mp::enable_if<all_are_where_clauses<mp::decay_t<T_clauses>...>>>
-        {
-            static constexpr decltype(auto) apply(T_clauses&&... clauses)
-                { return where_clause_or_t<T_clauses...>(std::forward<T_clauses>(clauses)...); }
-        };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where_clause_or
-        : public mp::is_specialization_of<T, __impl::where_clause_or_t>
-        { };
-
-    /* make */
-
-    constexpr decltype(auto) or_ = misc::make_generic_predicate<__impl::where_clause_or_builder> { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/conjunction.h b/include/cpphibernate/modifier/where/conjunction.h
new file mode 100644
index 0000000..5f96115
--- /dev/null
+++ b/include/cpphibernate/modifier/where/conjunction.h
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build conjunction objects.
+         */
+        template<typename X, typename = void>
+        struct conjunction_builder;
+
+    }
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a conjunction clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_conjunction;
+
+    /**
+     * @brief Is true if the passed type is a conjunction clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_conjunction_v = is_conjunction<T>::value;
+
+    /**
+     * @brief Predicate to create new conjunction clause objects.
+     */
+    constexpr decltype(auto) conjunction = mp::generic_predicate<__impl::conjunction_builder> { };
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a conjunction clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_and;
+
+    /**
+     * @brief Is true if the passed type is a conjunction clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_and_v = is_and<T>::value;
+
+    /**
+     * @brief Predicate to create new conjunction clause objects.
+     */
+    constexpr decltype(auto) and_ = mp::generic_predicate<__impl::conjunction_builder> { };
+
+}
+
+#include "conjunction.inl"
diff --git a/include/cpphibernate/modifier/where/conjunction.inl b/include/cpphibernate/modifier/where/conjunction.inl
new file mode 100644
index 0000000..f57bc35
--- /dev/null
+++ b/include/cpphibernate/modifier/where/conjunction.inl
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <cpphibernate/schema/field.h>
+
+#include "conjunction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* where_clause_conjunction_t */
+
+        template<typename... T_clauses>
+        struct where_clause_conjunction_t
+            : public tag_where_clause
+        {
+            using clauses_type = hana::basic_tuple<T_clauses...>;
+
+            clauses_type clauses;
+
+            constexpr where_clause_conjunction_t(
+                T_clauses&&... p_clauses)
+                : clauses(std::forward<T_clauses>(p_clauses)...)
+                { }
+        };
+
+        /* conjunction_builder */
+
+        template<typename X, typename>
+        struct conjunction_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::conjunction(...)!"); }
+        };
+
+        template<typename... T_clauses>
+        struct conjunction_builder<
+            mp::list<T_clauses...>,
+            mp::enable_if_t<
+                    mp::is_true_v<is_where_clause_v<mp::decay_t<T_clauses>>...>
+                &&  sizeof...(T_clauses) >= 2>>
+        {
+            static constexpr decltype(auto) apply(T_clauses&&... clauses)
+            {
+                using clause_type = where_clause_conjunction_t<T_clauses...>;
+                return clause_type(std::forward<T_clauses>(clauses)...);
+            }
+        };
+
+    }
+
+    /* is_conjunction */
+
+    template<typename T>
+    struct is_conjunction
+        : public mp::is_specialization_of<T, __impl::where_clause_conjunction_t>
+        { };
+
+    /* is_and */
+
+    template<typename T>
+    struct is_and
+        : public mp::is_specialization_of<T, __impl::where_clause_conjunction_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where/disjunction.h b/include/cpphibernate/modifier/where/disjunction.h
new file mode 100644
index 0000000..bc3e76e
--- /dev/null
+++ b/include/cpphibernate/modifier/where/disjunction.h
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build disjunction objects.
+         */
+        template<typename X, typename = void>
+        struct disjunction_builder;
+
+    }
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a disjunction clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_disjunction;
+
+    /**
+     * @brief Is true if the passed type is a disjunction clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_disjunction_v = is_disjunction<T>::value;
+
+    /**
+     * @brief Predicate to create new disjunction clause objects.
+     */
+    constexpr decltype(auto) disjunction = mp::generic_predicate<__impl::disjunction_builder> { };
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a disjunction clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_or;
+
+    /**
+     * @brief Is true if the passed type is a disjunction clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_or_v = is_or<T>::value;
+
+    /**
+     * @brief Predicate to create new disjunction clause objects.
+     */
+    constexpr decltype(auto) or_ = mp::generic_predicate<__impl::disjunction_builder> { };
+
+}
+
+#include "disjunction.inl"
diff --git a/include/cpphibernate/modifier/where/disjunction.inl b/include/cpphibernate/modifier/where/disjunction.inl
new file mode 100644
index 0000000..0e50791
--- /dev/null
+++ b/include/cpphibernate/modifier/where/disjunction.inl
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <cpphibernate/schema/field.h>
+
+#include "disjunction.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* where_clause_disjunction_t */
+
+        template<typename... T_clauses>
+        struct where_clause_disjunction_t
+            : public tag_where_clause
+        {
+            using clauses_type = hana::basic_tuple<T_clauses...>;
+
+            clauses_type clauses;
+
+            constexpr where_clause_disjunction_t(
+                T_clauses&&... p_clauses)
+                : clauses(std::forward<T_clauses>(p_clauses)...)
+                { }
+        };
+
+        /* disjunction_builder */
+
+        template<typename X, typename>
+        struct disjunction_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::disjunction(...)!"); }
+        };
+
+        template<typename... T_clauses>
+        struct disjunction_builder<
+            mp::list<T_clauses...>,
+            mp::enable_if_t<
+                    mp::is_true_v<is_where_clause_v<mp::decay_t<T_clauses>>...>
+                &&  sizeof...(T_clauses) >= 2>>
+        {
+            static constexpr decltype(auto) apply(T_clauses&&... clauses)
+            {
+                using clause_type = where_clause_disjunction_t<T_clauses...>;
+                return clause_type(std::forward<T_clauses>(clauses)...);
+            }
+        };
+
+    }
+
+    /* is_disjunction */
+
+    template<typename T>
+    struct is_disjunction
+        : public mp::is_specialization_of<T, __impl::where_clause_disjunction_t>
+        { };
+
+    /* is_or */
+
+    template<typename T>
+    struct is_or
+        : public mp::is_specialization_of<T, __impl::where_clause_disjunction_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where/equal.h b/include/cpphibernate/modifier/where/equal.h
new file mode 100644
index 0000000..c35b6db
--- /dev/null
+++ b/include/cpphibernate/modifier/where/equal.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build equal objects.
+         */
+        template<typename X, typename = void>
+        struct equal_builder;
+
+    }
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a equal order, false_t otherwise.
+     */
+    template<typename T>
+    struct is_equal;
+
+    /**
+     * @brief Is true if the passed type is a equal order, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_equal_v = is_equal<T>::value;
+
+    /**
+     * @brief Predicate to create new equal order objects.
+     */
+    constexpr decltype(auto) equal = mp::generic_predicate<__impl::equal_builder> { };
+
+}
+
+#include "equal.inl"
diff --git a/include/cpphibernate/modifier/where/equal.inl b/include/cpphibernate/modifier/where/equal.inl
new file mode 100644
index 0000000..1a13346
--- /dev/null
+++ b/include/cpphibernate/modifier/where/equal.inl
@@ -0,0 +1,64 @@
+#pragma once
+
+#include <cpphibernate/schema/field.h>
+
+#include "equal.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* where_clause_equal_t */
+
+        template<typename T_field, typename T_value>
+        struct where_clause_equal_t
+            : public tag_where_clause
+        {
+            using field_type = T_field;
+            using value_type = T_value;
+
+            field_type field;
+            value_type value;
+
+            constexpr where_clause_equal_t(
+                field_type&& p_field,
+                value_type&& p_value)
+                : field(std::forward<field_type>(p_field))
+                , value(std::forward<value_type>(p_value))
+                { }
+        };
+
+        /* equal_builder */
+
+        template<typename X, typename>
+        struct equal_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::equal(...)!"); }
+        };
+
+        template<typename T_field, typename T_value>
+        struct equal_builder<
+            mp::list<T_field, T_value>,
+            mp::enable_if_t<schema::is_field_v<mp::decay_t<T_field>>>>
+        {
+            static constexpr decltype(auto) apply(T_field&& field, T_value&& value)
+            {
+                using clause_type = where_clause_equal_t<T_field, T_value>;
+                return clause_type(std::forward<T_field>(field), std::forward<T_value>(value));
+            }
+        };
+
+    }
+
+    /* is_equal */
+
+    template<typename T>
+    struct is_equal
+        : public mp::is_specialization_of<T, __impl::where_clause_equal_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where/negation.h b/include/cpphibernate/modifier/where/negation.h
new file mode 100644
index 0000000..ad49dd8
--- /dev/null
+++ b/include/cpphibernate/modifier/where/negation.h
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /**
+         * @brief Helper class to build negation objects.
+         */
+        template<typename X, typename = void>
+        struct negation_builder;
+
+    }
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a negation clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_negation;
+
+    /**
+     * @brief Is true if the passed type is a negation clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_negation_v = is_negation<T>::value;
+
+    /**
+     * @brief Predicate to create new negation clause objects.
+     */
+    constexpr decltype(auto) negation = mp::generic_predicate<__impl::negation_builder> { };
+
+
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a negation clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_not;
+
+    /**
+     * @brief Is true if the passed type is a negation clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_not_v = is_not<T>::value;
+
+    /**
+     * @brief Predicate to create new negation clause objects.
+     */
+    constexpr decltype(auto) not_ = mp::generic_predicate<__impl::negation_builder> { };
+
+}
+
+#include "negation.inl"
diff --git a/include/cpphibernate/modifier/where/negation.inl b/include/cpphibernate/modifier/where/negation.inl
new file mode 100644
index 0000000..6ee91a5
--- /dev/null
+++ b/include/cpphibernate/modifier/where/negation.inl
@@ -0,0 +1,67 @@
+#pragma once
+
+#include <cpphibernate/schema/field.h>
+
+#include "negation.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* where_clause_negation_t */
+
+        template<typename T_clause>
+        struct where_clause_negation_t
+            : public tag_where_clause
+        {
+            using clause_type = T_clause;
+
+            clause_type clause;
+
+            constexpr where_clause_negation_t(
+                clause_type&& p_clause)
+                : clause(std::forward<clause_type>(p_clause))
+                { }
+        };
+
+        /* negation_builder */
+
+        template<typename X, typename>
+        struct negation_builder
+        {
+            template<typename... T_args>
+            static constexpr decltype(auto) apply(T_args&&... args)
+                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::negation(...)!"); }
+        };
+
+        template<typename T_clause>
+        struct negation_builder<
+            mp::list<T_clause>,
+            mp::enable_if_t<is_where_clause_v<mp::decay_t<T_clause>>>>
+        {
+            static constexpr decltype(auto) apply(T_clause&& clause)
+            {
+                using clause_type = where_clause_negation_t<T_clause>;
+                return clause_type(std::forward<T_clause>(clause));
+            }
+        };
+
+    }
+
+    /* is_negation */
+
+    template<typename T>
+    struct is_negation
+        : public mp::is_specialization_of<T, __impl::where_clause_negation_t>
+        { };
+
+    /* is_not */
+
+    template<typename T>
+    struct is_not
+        : public mp::is_specialization_of<T, __impl::where_clause_negation_t>
+        { };
+
+}
diff --git a/include/cpphibernate/modifier/where/where.h b/include/cpphibernate/modifier/where/where.h
deleted file mode 100644
index 685e24a..0000000
--- a/include/cpphibernate/modifier/where/where.h
+++ /dev/null
@@ -1,60 +0,0 @@
-#pragma once
-
-#include <cpphibernate/misc.h>
-#include <cpphibernate/config.h>
-#include <cpphibernate/modifier/modifier.h>
-#include <cpphibernate/modifier/where/clauses/clause.h>
-
-beg_namespace_cpphibernate_modifier
-{
-
-    namespace __impl
-    {
-
-        /* where_t */
-
-        template<typename T_clause>
-        struct where_t
-            : public modifier_t
-        {
-            using clause_type = T_clause;
-
-            clause_type clause;
-
-            constexpr where_t(T_clause&& p_clause)
-                : clause(std::forward<T_clause>(p_clause))
-                { }
-        };
-
-        /* where_builder */
-
-        template<typename X, typename = void>
-        struct where_builder
-        {
-            template<typename... T_args>
-            static constexpr decltype(auto) apply(T_args&&... args)
-                { static_assert(sizeof...(args) == -1, "Invalid parameters for hibernate::modifier::where(...)!"); }
-        };
-
-        template<typename T_clause>
-        struct where_builder<mp::list<T_clause>, mp::enable_if<is_where_clause<T_clause>>>
-        {
-            static constexpr decltype(auto) apply(T_clause&& clause)
-                { return where_t<T_clause>(std::forward<T_clause>(clause)); }
-        };
-
-    }
-
-    /* meta */
-
-    template<typename T>
-    struct is_where
-        : public mp::is_specialization_of<T, __impl::where_t>
-        { };
-
-    /* make */
-
-    constexpr decltype(auto) where = misc::make_generic_predicate<__impl::where_builder> { };
-
-}
-end_namespace_cpphibernate_modifier
\ No newline at end of file
diff --git a/include/cpphibernate/modifier/where/where_clause.h b/include/cpphibernate/modifier/where/where_clause.h
new file mode 100644
index 0000000..d4d774a
--- /dev/null
+++ b/include/cpphibernate/modifier/where/where_clause.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <cpphibernate/config.h>
+
+namespace cpphibernate
+{
+
+    /**
+     * @brief Evaluates to true_t if the passed type is a where_clause, false_t otherwise.
+     */
+    template<typename T>
+    struct is_where_clause;
+
+    /**
+     * @brief Is true if the passed type is a where_clause, false otherwise.
+     */
+    template<typename T>
+    constexpr decltype(auto) is_where_clause_v = is_where_clause<T>::value;
+
+}
+
+#include "where_clause.inl"
diff --git a/include/cpphibernate/modifier/where/where_clause.inl b/include/cpphibernate/modifier/where/where_clause.inl
new file mode 100644
index 0000000..446a2e0
--- /dev/null
+++ b/include/cpphibernate/modifier/where/where_clause.inl
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "where_clause.h"
+
+namespace cpphibernate
+{
+
+    namespace __impl
+    {
+
+        /* tag_where_clause */
+
+        struct tag_where_clause
+            { };
+
+    }
+
+    /* is_where_clause */
+
+    template<typename T>
+    struct is_where_clause
+        : public mp::is_base_of<__impl::tag_where_clause, T>
+        { };
+
+}
diff --git a/include/cpphibernate/schema/attributes.inl b/include/cpphibernate/schema/attributes.inl
index a333cb8..8d72793 100644
--- a/include/cpphibernate/schema/attributes.inl
+++ b/include/cpphibernate/schema/attributes.inl
@@ -11,7 +11,7 @@ namespace schema {
         /* attributes_t */
 
         template<typename... T_attributes>
-        using attributes_t = hana::basic_tuple<T_attributes...>;
+        using attributes_t = hana::tuple<T_attributes...>;
 
         /* attributes_builder */
 
diff --git a/include/cpphibernate/schema/fields.inl b/include/cpphibernate/schema/fields.inl
index 386d231..8ed2800 100644
--- a/include/cpphibernate/schema/fields.inl
+++ b/include/cpphibernate/schema/fields.inl
@@ -11,7 +11,7 @@ namespace schema {
         /* fields_t */
 
         template<typename... T_fields>
-        using fields_t = hana::basic_tuple<T_fields...>;
+        using fields_t = hana::tuple<T_fields...>;
 
         /* fields_builder */
 
diff --git a/include/cpphibernate/schema/tables.inl b/include/cpphibernate/schema/tables.inl
index 72ec401..22feefd 100644
--- a/include/cpphibernate/schema/tables.inl
+++ b/include/cpphibernate/schema/tables.inl
@@ -11,7 +11,7 @@ namespace schema {
         /* tables_t */
 
         template<typename... T_tables>
-        using tables_t = hana::basic_tuple<T_tables...>;
+        using tables_t = hana::tuple<T_tables...>;
 
         /* tables_builder */
 
diff --git a/test/cpphibernate/cpphibernate_tests.cpp b/test/cpphibernate/cpphibernate_tests.cpp
index f1c3863..a6c2e50 100644
--- a/test/cpphibernate/cpphibernate_tests.cpp
+++ b/test/cpphibernate/cpphibernate_tests.cpp
@@ -4,17 +4,26 @@
 
 #include "test_schema.h"
 
-constexpr decltype(auto) x = ::cpphibernate::mp::make_getter(
-            [](std::string&) {
-                return int { };
-            });
-
 using namespace ::testing;
 using namespace ::cpphibernate;
 using namespace ::cpphibernate::schema;
 
-TEST(cpphibernate, getHelloWorld)
+using namespace hana::literals;
+
+constexpr decltype(auto) tmp_table = test_schema.tables[0_c];
+constexpr decltype(auto) tmp_field = tmp_table.fields[0_c];
+constexpr decltype(auto) mod = make_modifiers(
+    limit(5_c),
+    offset(3_c),
+    order_by(
+        ascending(tmp_field),
+        descending(tmp_field)),
+    where(
+        or_(
+            negation(equal(tmp_field, 1)),
+            negation(equal(tmp_field, 1)))));
+
+TEST(cpphibernate_tests, dummy)
 {
-    (void)x;
-    // std::cout << test_schema << std::endl;
+    (void)mod;
 }
diff --git a/test/test_schema.h b/test/test_schema.h
deleted file mode 100644
index 0437940..0000000
--- a/test/test_schema.h
+++ /dev/null
@@ -1,236 +0,0 @@
-#pragma once
-
-#include <cpphibernate.h>
-#include <cpputils/misc/enum.h>
-
-enum class test_enum
-{
-    test0,
-    test1,
-    test2,
-    test3,
-
-    first = test0,
-    last  = test3,
-};
-
-DEFINE_ENUM_TO_STRING_MAP(
-    test_enum,
-    { test_enum::test0, "test0" },
-    { test_enum::test1, "test1" },
-    { test_enum::test2, "test2" },
-    { test_enum::test3, "test3" }
-);
-
-DEFINE_STRING_TO_ENUM_MAP(
-    test_enum,
-    invariant_string_less,
-    { "test0", test_enum::test0 },
-    { "test1", test_enum::test1 },
-    { "test2", test_enum::test2 },
-    { "test3", test_enum::test3 }
-);
-
-struct test1
-{
-    ::cpphibernate::uuid        id;
-    std::string                 str_data;
-    ::cpphibernate::string<64>  str64_data;
-
-    utl::nullable<uint32_t>     u32_nullable;
-    std::unique_ptr<uint32_t>   u32_ptr_u;
-    std::shared_ptr<uint32_t>   u32_ptr_s;
-};
-
-struct test2
-{
-    ::cpphibernate::uuid        id;
-    uint8_t                     u8_data;
-    int8_t                      i8_data;
-    uint16_t                    u16_data;
-    int16_t                     i16_data;
-};
-
-struct test3
-{
-    ::cpphibernate::uuid        id;
-    uint32_t                    u32_data;
-    int32_t                     i32_data;
-    uint64_t                    u64_data;
-    int64_t                     i64_data;
-};
-
-struct base
-{
-    ::cpphibernate::uuid        id;
-    std::string                 name;
-
-    virtual ~base() = default;
-};
-
-struct derived1
-    : public base
-{
-    ::cpphibernate::uuid        derived1_id;
-    test1                       test1_data;
-    test_enum                   enum_data;
-};
-
-struct derived2
-    : public base
-{
-    ::cpphibernate::uuid        derived2_id;
-    utl::nullable<test2>        test2_nullable;
-    std::unique_ptr<test2>      test2_ptr_u;
-    std::shared_ptr<test2>      test2_ptr_s;
-};
-
-struct derived3
-    : public derived2
-{
-    ::cpphibernate::uuid        derived3_id;
-    std::list<test3>            test3_list;
-    std::vector<test3>          test3_vector;
-};
-
-struct dummy_id
-{
-    int data;
-
-    inline dummy_id(int p_data = 0)
-        : data(p_data)
-        { }
-};
-
-struct dummy_owner
-{
-    ::cpphibernate::uuid    id;
-    std::vector<dummy_id>   dummies;
-};
-
-struct double_usage_item
-{
-    unsigned int            id          { 0 };
-    int                     data        { 0 };
-
-    double_usage_item(int p_data = 0)
-        : data(p_data)
-        { }
-};
-
-struct double_usage
-{
-    int                                 id              { 0 };
-    std::unique_ptr<double_usage_item>  single_item;
-    std::vector<double_usage_item>      multiple_items;
-};
-
-struct double_usage_wrapper
-{
-    int                                 id              { 0 };
-    std::unique_ptr<double_usage>       double_usage;
-};
-
-constexpr decltype(auto) test_schema = cpphibernate_make_schema(
-    test,
-    cpphibernate_make_table_name(
-        tbl_test1,
-        test1,
-        1,
-        cpphibernate_make_id          (&test1::id),
-        cpphibernate_make_field       (test1, str_data),
-        cpphibernate_make_field       (test1, str64_data),
-        cpphibernate_make_field       (test1, u32_nullable),
-        cpphibernate_make_field       (test1, u32_ptr_u),
-        cpphibernate_make_field       (test1, u32_ptr_s)
-    ),
-    cpphibernate_make_table_name(
-        tbl_test2,
-        test2,
-        2,
-        cpphibernate_make_id          (&test2::id),
-        cpphibernate_make_field       (test2, u8_data),
-        cpphibernate_make_field       (test2, i8_data),
-        cpphibernate_make_field       (test2, u16_data),
-        cpphibernate_make_field       (test2, i16_data)
-    ),
-    cpphibernate_make_table_name(
-        tbl_test3,
-        test3,
-        3,
-        cpphibernate_make_id          (&test3::id),
-        cpphibernate_make_field       (test3, u32_data),
-        cpphibernate_make_field       (test3, i32_data),
-        cpphibernate_make_field       (test3, u64_data),
-        cpphibernate_make_field       (test3, i64_data)
-    ),
-
-    cpphibernate_make_table_name(
-        tbl_base,
-        base,
-        10,
-        cpphibernate_make_id          (&base::id),
-        cpphibernate_make_field       (base, name)
-    ),
-    cpphibernate_make_table_name(
-        tbl_derived1,
-        derived1,
-        11,
-        cpphibernate_make_id          (&derived1::derived1_id),
-        cpphibernate_make_field       (derived1, test1_data),
-        cpphibernate_make_field       (derived1, enum_data)
-    ),
-    cpphibernate_make_table_name(
-        tbl_derived2,
-        derived2,
-        12,
-        cpphibernate_make_id          (&derived2::derived2_id),
-        cpphibernate_make_field       (derived2, test2_nullable),
-        cpphibernate_make_field       (derived2, test2_ptr_u),
-        cpphibernate_make_field       (derived2, test2_ptr_s)
-    ),
-    cpphibernate_make_table_name(
-        tbl_derived3,
-        derived3,
-        13,
-        cpphibernate_make_id          (&derived3::derived3_id),
-        cpphibernate_make_field       (derived3, test3_list),
-        cpphibernate_make_field       (derived3, test3_vector)
-    ),
-    cpphibernate_make_table_name(
-        tbl_dummy_id,
-        dummy_id,
-        14,
-        cpphibernate_make_temp_id     (dummy_id, ::cpphibernate::uuid),
-        cpphibernate_make_field       (dummy_id, data)
-    ),
-    cpphibernate_make_table_name(
-        tbl_dummy_owner,
-        dummy_owner,
-        15,
-        cpphibernate_make_id          (&dummy_owner::id),
-        cpphibernate_make_field       (dummy_owner, dummies)
-    ),
-    cpphibernate_make_table_name(
-        tbl_double_usage_item,
-        double_usage_item,
-        16,
-        cpphibernate_make_id          (&double_usage_item::id),
-        cpphibernate_make_field       (double_usage_item, data)
-    ),
-    cpphibernate_make_table_name(
-        tbl_double_usage,
-        double_usage,
-        17,
-        cpphibernate_make_id          (&double_usage::id),
-        cpphibernate_make_field       (double_usage, single_item),
-        cpphibernate_make_field       (double_usage, multiple_items)
-    ),
-    cpphibernate_make_table_name(
-        tbl_double_usage_wrapper,
-        double_usage_wrapper,
-        18,
-        cpphibernate_make_id          (&double_usage_wrapper::id),
-        cpphibernate_make_field       (double_usage_wrapper, double_usage)
-    )
-);
\ No newline at end of file