mirror of
https://github.com/rbock/sqlpp11.git
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262 lines
7.1 KiB
C++
262 lines
7.1 KiB
C++
/*
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* Copyright (c) 2013-2014, Roland Bock
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef SQLPP_LIMIT_H
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#define SQLPP_LIMIT_H
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#include <sqlpp11/type_traits.h>
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#include <sqlpp11/policy_update.h>
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#include <sqlpp11/detail/type_set.h>
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namespace sqlpp
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{
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// LIMIT DATA
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template<typename Limit>
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struct limit_data_t
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{
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limit_data_t(Limit value):
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_value(value)
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{}
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limit_data_t(const limit_data_t&) = default;
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limit_data_t(limit_data_t&&) = default;
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limit_data_t& operator=(const limit_data_t&) = default;
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limit_data_t& operator=(limit_data_t&&) = default;
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~limit_data_t() = default;
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Limit _value;
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};
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// LIMIT
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template<typename Limit>
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struct limit_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_limit>;
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using _recursive_traits = make_recursive_traits<Limit>;
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static_assert(is_integral_t<Limit>::value, "limit requires an integral value or integral parameter");
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// Data
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using _data_t = limit_data_t<Limit>;
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// Member implementation with data and methods
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template <typename Policies>
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struct _impl_t
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{
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_data_t _data;
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};
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// Member template for adding the named member to a statement
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template<typename Policies>
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struct _member_t
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{
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using _data_t = limit_data_t<Limit>;
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_impl_t<Policies> limit;
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_impl_t<Policies>& operator()() { return limit; }
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const _impl_t<Policies>& operator()() const { return limit; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.limit)
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{
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return t.limit;
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}
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};
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template<typename Policies>
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struct _methods_t
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{
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static void _check_consistency() {}
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};
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};
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// DYNAMIC LIMIT DATA
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template<typename Database>
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struct dynamic_limit_data_t
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{
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dynamic_limit_data_t():
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_value(noop())
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{
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}
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template<typename Limit>
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dynamic_limit_data_t(Limit value):
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_initialized(true),
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_value(typename wrap_operand<Limit>::type(value))
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{
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}
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dynamic_limit_data_t(const dynamic_limit_data_t&) = default;
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dynamic_limit_data_t(dynamic_limit_data_t&&) = default;
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dynamic_limit_data_t& operator=(const dynamic_limit_data_t&) = default;
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dynamic_limit_data_t& operator=(dynamic_limit_data_t&&) = default;
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~dynamic_limit_data_t() = default;
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bool _initialized = false;
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interpretable_t<Database> _value;
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};
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// DYNAMIC LIMIT
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template<typename Database>
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struct dynamic_limit_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_limit>;
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using _recursive_traits = make_recursive_traits<>;
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// Data
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using _data_t = dynamic_limit_data_t<Database>;
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// Member implementation with data and methods
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template <typename Policies>
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struct _impl_t
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{
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template<typename Limit>
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void set(Limit value)
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{
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// FIXME: Make sure that Limit does not require external tables? Need to read up on SQL
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using arg_t = typename wrap_operand<Limit>::type;
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_data._value = arg_t{value};
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_data._initialized = true;
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}
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public:
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_data_t _data;
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};
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// Member template for adding the named member to a statement
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template<typename Policies>
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struct _member_t
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{
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using _data_t = dynamic_limit_data_t<Database>;
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_impl_t<Policies> limit;
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_impl_t<Policies>& operator()() { return limit; }
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const _impl_t<Policies>& operator()() const { return limit; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.limit)
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{
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return t.limit;
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}
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};
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// Additional methods for the statement
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template<typename Policies>
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struct _methods_t
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{
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static void _check_consistency() {}
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};
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};
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struct no_limit_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_noop>;
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using _recursive_traits = make_recursive_traits<>;
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// Data
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using _data_t = no_data_t;
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// Member implementation with data and methods
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template<typename Policies>
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struct _impl_t
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{
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_data_t _data;
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};
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// Member template for adding the named member to a statement
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template<typename Policies>
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struct _member_t
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{
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using _data_t = no_data_t;
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_impl_t<Policies> no_limit;
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_impl_t<Policies>& operator()() { return no_limit; }
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const _impl_t<Policies>& operator()() const { return no_limit; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.no_limit)
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{
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return t.no_limit;
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}
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};
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template<typename Policies>
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struct _methods_t
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{
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using _database_t = typename Policies::_database_t;
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template<typename T>
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using _new_statement_t = typename Policies::template _new_statement_t<no_limit_t, T>;
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static void _check_consistency() {}
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template<typename Arg>
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auto limit(Arg arg)
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-> _new_statement_t<limit_t<typename wrap_operand<Arg>::type>>
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{
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return { *static_cast<typename Policies::_statement_t*>(this), limit_data_t<typename wrap_operand<Arg>::type>{{arg}} };
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}
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auto dynamic_limit()
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-> _new_statement_t<dynamic_limit_t<_database_t>>
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{
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static_assert(not std::is_same<_database_t, void>::value, "dynamic_limit must not be called in a static statement");
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return { *static_cast<typename Policies::_statement_t*>(this), dynamic_limit_data_t<_database_t>{} };
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}
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};
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};
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// Interpreters
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template<typename Context, typename Database>
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struct serializer_t<Context, dynamic_limit_data_t<Database>>
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{
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using T = dynamic_limit_data_t<Database>;
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static Context& _(const T& t, Context& context)
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{
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if (t._initialized)
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{
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context << " LIMIT ";
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serialize(t._value, context);
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}
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return context;
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}
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};
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template<typename Context, typename Limit>
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struct serializer_t<Context, limit_data_t<Limit>>
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{
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using T = limit_data_t<Limit>;
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static Context& _(const T& t, Context& context)
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{
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context << " LIMIT ";
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serialize(t._value, context);
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return context;
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}
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};
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}
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#endif
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