diff --git a/include/sqlpp11/basic_operators.h b/include/sqlpp11/basic_operators.h
index a7340a9f..6fb3d893 100644
--- a/include/sqlpp11/basic_operators.h
+++ b/include/sqlpp11/basic_operators.h
@@ -41,34 +41,6 @@ namespace sqlpp
 		struct boolean;
 	}
 
-	namespace vendor
-	{
-		// operators
-		struct lt_
-		{
-			using _value_type = detail::boolean;
-			static constexpr const char* _name = "<";
-		};
-
-		struct le_
-		{
-			using _value_type = detail::boolean;
-			static constexpr const char* _name = "<=";
-		};
-
-		struct ge_
-		{
-			using _value_type = detail::boolean;
-			static constexpr const char* _name = ">=";
-		};
-
-		struct gt_
-		{
-			using _value_type = detail::boolean;
-			static constexpr const char* _name = ">";
-		};
-	}
-
 	// basic operators
 	template<typename Base, template<typename> class Constraint>
 		struct basic_operators
@@ -87,28 +59,28 @@ namespace sqlpp
 					return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 				}
 			template<typename T>
-				vendor::binary_expression_t<Base, vendor::lt_, typename Constraint<T>::type> operator<(T&& t) const
+				vendor::less_than_t<Base, typename Constraint<T>::type> operator<(T&& t) const
 				{
 					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 					return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 				}
 
 			template<typename T>
-				vendor::binary_expression_t<Base, vendor::le_, typename Constraint<T>::type> operator<=(T&& t) const
+				vendor::less_equal_t<Base, typename Constraint<T>::type> operator<=(T&& t) const
 				{
 					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 					return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 				}
 
 			template<typename T>
-				vendor::binary_expression_t<Base, vendor::ge_, typename Constraint<T>::type> operator>=(T&& t) const
+				vendor::greater_than_t<Base, typename Constraint<T>::type> operator>(T&& t) const
 				{
 					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 					return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 				}
 
 			template<typename T>
-				vendor::binary_expression_t<Base, vendor::gt_, typename Constraint<T>::type> operator>(T&& t) const
+				vendor::greater_equal_t<Base, typename Constraint<T>::type> operator>=(T&& t) const
 				{
 					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 					return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
diff --git a/include/sqlpp11/boolean.h b/include/sqlpp11/boolean.h
index 29253d4e..8aefdb30 100644
--- a/include/sqlpp11/boolean.h
+++ b/include/sqlpp11/boolean.h
@@ -38,18 +38,6 @@ namespace sqlpp
 	// boolean operators
 	namespace detail
 	{
-		struct or_
-		{
-			using _value_type = boolean;
-			static constexpr const char* _name = " OR ";
-		};
-
-		struct and_
-		{
-			using _value_type = boolean;
-			static constexpr const char* _name = " AND ";
-		};
-
 		// boolean value type
 		struct boolean
 		{
@@ -178,20 +166,20 @@ namespace sqlpp
 				struct operators: public basic_operators<Base, _constraint>
 			{
 				template<typename T>
-					vendor::binary_expression_t<Base, and_, typename _constraint<T>::type> operator and(T&& t) const
+					vendor::logical_and_t<Base, typename _constraint<T>::type> operator and(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, or_, typename _constraint<T>::type> operator or(T&& t) const
+					vendor::logical_or_t<Base, typename _constraint<T>::type> operator or(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
-				vendor::not_t<Base> operator not() const
+				vendor::logical_not_t<Base> operator not() const
 				{
 					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be as operand for operator not");
 					return { *static_cast<const Base*>(this) };
diff --git a/include/sqlpp11/floating_point.h b/include/sqlpp11/floating_point.h
index c7b757e9..ea1bce12 100644
--- a/include/sqlpp11/floating_point.h
+++ b/include/sqlpp11/floating_point.h
@@ -161,30 +161,6 @@ namespace sqlpp
 				_cpp_value_type _value;
 			};
 
-			struct plus_
-			{
-				using _value_type = floating_point;
-				static constexpr const char* _name = "+";
-			};
-
-			struct minus_
-			{
-				using _value_type = floating_point;
-				static constexpr const char* _name = "-";
-			};
-
-			struct multiplies_
-			{
-				using _value_type = floating_point;
-				static constexpr const char* _name = "*";
-			};
-
-			struct divides_
-			{
-				using _value_type = floating_point;
-				static constexpr const char* _name = "/";
-			};
-
 			template<typename T>
 				using _constraint = operand_t<T, is_numeric_t>;
 
@@ -192,33 +168,45 @@ namespace sqlpp
 				struct operators: public basic_operators<Base, _constraint>
 			{
 				template<typename T>
-					vendor::binary_expression_t<Base, plus_, typename _constraint<T>::type> operator +(T&& t) const
+					vendor::plus_t<Base, floating_point, typename _constraint<T>::type> operator +(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, minus_, typename _constraint<T>::type> operator -(T&& t) const
+					vendor::minus_t<Base, floating_point, typename _constraint<T>::type> operator -(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, multiplies_, typename _constraint<T>::type> operator *(T&& t) const
+					vendor::multiplies_t<Base, floating_point, typename _constraint<T>::type> operator *(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, divides_, typename _constraint<T>::type> operator /(T&& t) const
+					vendor::divides_t<Base, typename _constraint<T>::type> operator /(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
+				vendor::unary_plus_t<floating_point, Base> operator +() const
+				{
+					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
+					return { *static_cast<const Base*>(this) };
+				}
+
+				vendor::unary_minus_t<floating_point, Base> operator -() const
+				{
+					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
+					return { *static_cast<const Base*>(this) };
+				}
+
 				template<typename T>
 					auto operator +=(T&& t) const -> decltype(std::declval<Base>() = std::declval<Base>() + std::forward<T>(t))
 					{
diff --git a/include/sqlpp11/integral.h b/include/sqlpp11/integral.h
index d6fb4e26..308014dc 100644
--- a/include/sqlpp11/integral.h
+++ b/include/sqlpp11/integral.h
@@ -31,6 +31,7 @@
 #include <sqlpp11/basic_operators.h>
 #include <sqlpp11/type_traits.h>
 #include <sqlpp11/exception.h>
+#include <sqlpp11/vendor/value_type.h>
 
 namespace sqlpp
 {
@@ -160,33 +161,6 @@ namespace sqlpp
 				_cpp_value_type _value;
 			};
 
-			template<typename T>
-			struct plus_
-			{
-				using _value_type = typename vendor::wrap_operand<typename std::decay<T>::type>::type::_value_type;
-				static constexpr const char* _name = "+";
-			};
-
-			template<typename T>
-			struct minus_
-			{
-				using _value_type = typename vendor::wrap_operand<typename std::decay<T>::type>::type::_value_type;
-				static constexpr const char* _name = "-";
-			};
-
-			template<typename T>
-			struct multiplies_
-			{
-				using _value_type = typename vendor::wrap_operand<typename std::decay<T>::type>::type::_value_type;
-				static constexpr const char* _name = "*";
-			};
-
-			struct divides_
-			{
-				using _value_type = floating_point;
-				static constexpr const char* _name = "/";
-			};
-
 			template<typename T>
 				using _constraint = operand_t<T, is_numeric_t>;
 
@@ -194,33 +168,52 @@ namespace sqlpp
 				struct operators: public basic_operators<Base, _constraint>
 			{
 				template<typename T>
-					vendor::binary_expression_t<Base, plus_<T>, typename _constraint<T>::type> operator +(T&& t) const
+					vendor::plus_t<Base, vendor::value_type_t<T>, typename _constraint<T>::type> operator +(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, minus_<T>, typename _constraint<T>::type> operator -(T&& t) const
+					vendor::minus_t<Base, vendor::value_type_t<T>, typename _constraint<T>::type> operator -(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, multiplies_<T>, typename _constraint<T>::type> operator *(T&& t) const
+					vendor::multiplies_t<Base, vendor::value_type_t<T>, typename _constraint<T>::type> operator *(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
 				template<typename T>
-					vendor::binary_expression_t<Base, divides_, typename _constraint<T>::type> operator /(T&& t) const
+					vendor::divides_t<Base, typename _constraint<T>::type> operator /(T&& t) const
 					{
 						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
 						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
 					}
 
+				template<typename T>
+					vendor::modulus_t<Base, typename _constraint<T>::type> operator %(T&& t) const
+					{
+						static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as left hand side operand");
+						return { *static_cast<const Base*>(this), {std::forward<T>(t)} };
+					}
+
+				vendor::unary_plus_t<integral, Base> operator +() const
+				{
+					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
+					return { *static_cast<const Base*>(this) };
+				}
+
+				vendor::unary_minus_t<integral, Base> operator -() const
+				{
+					static_assert(not is_multi_expression_t<Base>::value, "multi-expression cannot be used as unary operand");
+					return { *static_cast<const Base*>(this) };
+				}
+
 				template<typename T>
 					auto operator +=(T&& t) const -> decltype(std::declval<Base>() = std::declval<Base>() + std::forward<T>(t))
 					{
diff --git a/include/sqlpp11/vendor/expression.h b/include/sqlpp11/vendor/expression.h
index 5d63e506..ba66ef85 100644
--- a/include/sqlpp11/vendor/expression.h
+++ b/include/sqlpp11/vendor/expression.h
@@ -173,28 +173,28 @@ namespace sqlpp
 			};
 
 		template<typename Lhs>
-			struct not_t: public detail::boolean::template operators<not_t<Lhs>>
+			struct logical_not_t: public detail::boolean::template operators<logical_not_t<Lhs>>
 		{
 			using _value_type = detail::boolean;
 			using _parameter_tuple_t = std::tuple<Lhs>;
 
-			not_t(Lhs l):
+			logical_not_t(Lhs l):
 				_lhs(l)
 			{}
 
-			not_t(const not_t&) = default;
-			not_t(not_t&&) = default;
-			not_t& operator=(const not_t&) = default;
-			not_t& operator=(not_t&&) = default;
-			~not_t() = default;
+			logical_not_t(const logical_not_t&) = default;
+			logical_not_t(logical_not_t&&) = default;
+			logical_not_t& operator=(const logical_not_t&) = default;
+			logical_not_t& operator=(logical_not_t&&) = default;
+			~logical_not_t() = default;
 
 			Lhs _lhs;
 		};
 
 		template<typename Context, typename Lhs>
-			struct interpreter_t<Context, not_t<Lhs>>
+			struct interpreter_t<Context, logical_not_t<Lhs>>
 			{
-				using T = not_t<Lhs>;
+				using T = logical_not_t<Lhs>;
 
 				static Context& _(const T& t, Context& context)
 				{
@@ -242,6 +242,40 @@ namespace sqlpp
 					return context;
 				}
 			};
+
+		template<typename O, typename Rhs>
+			struct unary_expression_t: public O::_value_type::template operators<unary_expression_t<O, Rhs>>
+		{
+			using _value_type = typename O::_value_type;
+			using _parameter_tuple_t = std::tuple<Rhs>;
+
+			unary_expression_t(Rhs rhs):
+				_rhs(rhs)
+			{}
+
+			unary_expression_t(const unary_expression_t&) = default;
+			unary_expression_t(unary_expression_t&&) = default;
+			unary_expression_t& operator=(const unary_expression_t&) = default;
+			unary_expression_t& operator=(unary_expression_t&&) = default;
+			~unary_expression_t() = default;
+
+			Rhs _rhs;
+		};
+
+		template<typename Context, typename O, typename Rhs>
+			struct interpreter_t<Context, unary_expression_t<O, Rhs>>
+			{
+				using T = unary_expression_t<O, Rhs>;
+
+				static Context& _(const T& t, Context& context)
+				{
+					context << "(";
+					context << O::_name;
+					interpret(t._rhs, context);
+					context << ")";
+					return context;
+				}
+			};
 	}
 }
 
diff --git a/include/sqlpp11/vendor/expression_fwd.h b/include/sqlpp11/vendor/expression_fwd.h
index 9fef78fc..988ae2a7 100644
--- a/include/sqlpp11/vendor/expression_fwd.h
+++ b/include/sqlpp11/vendor/expression_fwd.h
@@ -41,10 +41,139 @@ namespace sqlpp
 			struct not_equal_t;
 
 		template<typename Lhs>
-			struct not_t;
+			struct logical_not_t;
+
+		namespace tag
+		{
+			struct less_than
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = "<";
+			};
+
+			struct less_equal
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = "<=";
+			};
+
+			struct greater_equal
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = ">=";
+			};
+
+			struct greater_than
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = ">";
+			};
+
+			struct logical_or
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = " OR ";
+			};
+
+			struct logical_and
+			{
+				using _value_type = detail::boolean;
+				static constexpr const char* _name = " AND ";
+			};
+
+			template<typename ValueType>
+			struct plus
+			{
+				using _value_type = ValueType;
+				static constexpr const char* _name = "+";
+			};
+
+			template<typename ValueType>
+			struct minus
+			{
+				using _value_type = ValueType;
+				static constexpr const char* _name = "-";
+			};
+
+			template<typename ValueType>
+			struct multiplies
+			{
+				using _value_type = ValueType;
+				static constexpr const char* _name = "*";
+			};
+
+			struct divides
+			{
+				using _value_type = detail::floating_point;
+				static constexpr const char* _name = "/";
+			};
+
+			struct modulus
+			{
+				using _value_type = detail::integral;
+				static constexpr const char* _name = "%";
+			};
+
+			template<typename ValueType>
+			struct unary_minus
+			{
+				using _value_type = ValueType;
+				static constexpr const char* _name = "-";
+			};
+
+			template<typename ValueType>
+			struct unary_plus
+			{
+				using _value_type = ValueType;
+				static constexpr const char* _name = "+";
+			};
+		}
 
 		template<typename Lhs, typename O, typename Rhs>
 			struct binary_expression_t;
+
+		template<typename O, typename Rhs>
+			struct unary_expression_t;
+
+		template<typename Lhs, typename Rhs>
+			using less_than_t = binary_expression_t<Lhs, tag::less_than, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using less_equal_t = binary_expression_t<Lhs, tag::less_equal, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using greater_than_t = binary_expression_t<Lhs, tag::greater_than, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using greater_equal_t = binary_expression_t<Lhs, tag::greater_equal, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using logical_and_t = binary_expression_t<Lhs, tag::logical_and, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using logical_or_t = binary_expression_t<Lhs, tag::logical_or, Rhs>;
+
+		template<typename Lhs, typename ValueType, typename Rhs>
+			using plus_t = binary_expression_t<Lhs, tag::plus<ValueType>, Rhs>;
+
+		template<typename Lhs, typename ValueType, typename Rhs>
+			using minus_t = binary_expression_t<Lhs, tag::minus<ValueType>, Rhs>;
+
+		template<typename Lhs, typename ValueType, typename Rhs>
+			using multiplies_t = binary_expression_t<Lhs, tag::multiplies<ValueType>, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using divides_t = binary_expression_t<Lhs, tag::divides, Rhs>;
+
+		template<typename Lhs, typename Rhs>
+			using modulus_t = binary_expression_t<Lhs, tag::modulus, Rhs>;
+
+		template<typename ValueType, typename Rhs>
+			using unary_plus_t = unary_expression_t<tag::unary_plus<ValueType>, Rhs>;
+
+		template<typename ValueType, typename Rhs>
+			using unary_minus_t = unary_expression_t<tag::unary_minus<ValueType>, Rhs>;
+
 	}
 }
 
diff --git a/include/sqlpp11/vendor/value_type.h b/include/sqlpp11/vendor/value_type.h
new file mode 100644
index 00000000..39ca78fb
--- /dev/null
+++ b/include/sqlpp11/vendor/value_type.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2013, Roland Bock
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 
+ *   Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ * 
+ *   Redistributions in binary form must reproduce the above copyright notice, this
+ *   list of conditions and the following disclaimer in the documentation and/or
+ *   other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SQLPP_VALUE_TYPE_H
+#define SQLPP_VALUE_TYPE_H
+
+#include <type_traits>
+#include <sqlpp11/vendor/wrap_operand.h>
+
+namespace sqlpp
+{
+	namespace vendor
+	{
+		template<typename T>
+			using value_type_t = typename wrap_operand<typename std::decay<T>::type>::type::_value_type;
+	}
+}
+#endif
diff --git a/tests/InterpretTest.cpp b/tests/InterpretTest.cpp
index eb8c137e..da620dba 100644
--- a/tests/InterpretTest.cpp
+++ b/tests/InterpretTest.cpp
@@ -43,6 +43,9 @@ int main()
 	TabSample t;
 
 	interpret(t.alpha, printer).flush();
+	interpret(-t.alpha, printer).flush();
+	interpret(+t.alpha, printer).flush();
+	interpret(-(t.alpha + 7), printer).flush();
 	interpret(t.alpha = 0, printer).flush();
 	interpret(t.alpha = sqlpp::tvin(0), printer).flush();
 	interpret(t.alpha == 0, printer).flush();