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291 lines
10 KiB
C++
291 lines
10 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_STATEMENT_H
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#define SQLPP_STATEMENT_H
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#include <sqlpp11/result.h>
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#include <sqlpp11/parameter_list.h>
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#include <sqlpp11/prepared_select.h>
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#include <sqlpp11/serialize.h>
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#include <sqlpp11/noop.h>
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#include <sqlpp11/policy_update.h>
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#include <sqlpp11/serializer.h>
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#include <sqlpp11/detail/get_first.h>
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#include <sqlpp11/detail/get_last.h>
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#include <sqlpp11/detail/pick_arg.h>
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namespace sqlpp
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{
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template<typename Db, typename... Policies>
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struct statement_t;
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struct assert_no_unknown_tables_t
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{
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using type = std::false_type;
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template<typename T = void>
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static void _()
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{
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static_assert(wrong_t<T>::value, "one clause requires tables which are otherwise not known in the statement");
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}
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};
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struct assert_no_parameters_t
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{
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using type = std::false_type;
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template<typename T = void>
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static void _()
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{
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static_assert(wrong_t<T>::value, "cannot run statements with parameters directly, use prepare instead");
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}
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};
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namespace detail
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{
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template<typename Db = void, typename... Policies>
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struct statement_policies_t
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{
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using _database_t = Db;
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using _statement_t = statement_t<Db, Policies...>;
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template<typename Needle, typename Replacement>
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struct _policies_update_t
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{
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static_assert(detail::is_element_of<Needle, make_type_set_t<Policies...>>::value, "policies update for non-policy class detected");
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using type = statement_t<Db, policy_update_t<Policies, Needle, Replacement>...>;
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};
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template<typename Needle, typename Replacement>
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using _new_statement_t = typename _policies_update_t<Needle, Replacement>::type;
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using _all_required_tables = detail::make_joined_set_t<required_tables_of<Policies>...>;
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using _all_provided_tables = detail::make_joined_set_t<provided_tables_of<Policies>...>;
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using _all_provided_outer_tables = detail::make_joined_set_t<provided_outer_tables_of<Policies>...>;
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using _all_extra_tables = detail::make_joined_set_t<extra_tables_of<Policies>...>;
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using _known_tables = detail::make_joined_set_t<_all_provided_tables, _all_extra_tables>;
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template<typename Expression>
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using _no_unknown_tables = detail::is_subset_of<required_tables_of<Expression>, _known_tables>;
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// The tables not covered by the from.
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using _required_tables = detail::make_difference_set_t<
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_all_required_tables,
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_all_provided_tables // Hint: extra_tables are not used here because they are just a helper for dynamic .add_*()
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>;
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using _result_type_provider = detail::get_last_if<is_return_value_t, noop, Policies...>;
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struct _result_methods_t: public _result_type_provider::template _result_methods_t<_statement_t>
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{};
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// A select can be used as a pseudo table if
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// - at least one column is selected
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// - the select is complete (leaks no tables)
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static constexpr bool _can_be_used_as_table()
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{
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return is_select_column_list_t<_result_type_provider>::value and _required_tables::size::value == 0
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? true
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: false;
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}
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using _value_type = typename std::conditional<
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logic::none_t<is_missing_t<Policies>::value...>::value,
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value_type_of<_result_type_provider>,
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no_value_t // if a required statement part is missing (e.g. columns in a select), then the statement cannot be used as a value
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>::type;
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using _can_be_null = logic::any_t<
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can_be_null_t<_result_type_provider>::value,
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detail::make_intersect_set_t<
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required_tables_of<_result_type_provider>,
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_all_provided_outer_tables
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>::size::value != 0>;
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using _traits = make_traits<_value_type, tag_if<tag::is_expression, not std::is_same<_value_type, no_value_t>::value>>;
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struct _recursive_traits
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{
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using _required_tables = statement_policies_t::_required_tables;
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using _provided_tables = detail::type_set<>;
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using _provided_outer_tables = detail::type_set<>;
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using _extra_tables = detail::type_set<>;
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using _parameters = detail::make_parameter_tuple_t<parameters_of<Policies>...>;
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using _tags = typename std::conditional<_can_be_null::value,
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detail::type_set<tag::can_be_null>,
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detail::type_set<>>::type;
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};
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using _table_check = typename std::conditional<_required_tables::size::value == 0,
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consistent_t, assert_no_unknown_tables_t>::type;
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using _parameter_check = typename std::conditional<std::tuple_size<typename _recursive_traits::_parameters>::value == 0,
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consistent_t, assert_no_parameters_t>::type;
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};
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}
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template<typename Db, typename... Policies>
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struct statement_t:
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public Policies::template _base_t<detail::statement_policies_t<Db, Policies...>>...,
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public expression_operators<statement_t<Db, Policies...>, value_type_of<detail::statement_policies_t<Db, Policies...>>>,
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public detail::statement_policies_t<Db, Policies...>::_result_methods_t
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{
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using _policies_t = typename detail::statement_policies_t<Db, Policies...>;
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using _run_check = detail::get_first_if<is_inconsistent_t, consistent_t,
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typename _policies_t::_parameter_check,
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typename Policies::template _base_t<_policies_t>::_consistency_check...,
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typename _policies_t::_table_check>;
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using _prepare_check = detail::get_first_if<is_inconsistent_t, consistent_t,
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typename Policies::template _base_t<_policies_t>::_consistency_check...,
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typename _policies_t::_table_check>;
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using _result_type_provider = typename _policies_t::_result_type_provider;
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template<typename Composite>
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using _result_methods_t = typename _result_type_provider::template _result_methods_t<Composite>;
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using _traits = make_traits<value_type_of<_policies_t>,
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tag::is_statement,
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tag_if<tag::is_select, logic::any_t<is_select_t<Policies>::value...>::value>,
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tag_if<tag::is_expression, is_expression_t<_policies_t>::value>,
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tag_if<tag::is_selectable, is_expression_t<_policies_t>::value>,
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tag_if<tag::is_return_value, logic::none_t<is_noop_t<_result_type_provider>::value>::value>,
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tag::requires_braces>;
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using _recursive_traits = typename _policies_t::_recursive_traits;
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using _used_outer_tables = typename _policies_t::_all_provided_outer_tables;
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using _name_t = typename _result_type_provider::_name_t;
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// Constructors
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statement_t()
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{}
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template<typename Statement, typename Term>
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statement_t(Statement statement, Term term):
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Policies::template _base_t<_policies_t>{
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typename Policies::template _impl_t<_policies_t>{
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detail::pick_arg<typename Policies::template _base_t<_policies_t>>(statement, term)
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}}...
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{}
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statement_t(const statement_t& r) = default;
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statement_t(statement_t&& r) = default;
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statement_t& operator=(const statement_t& r) = default;
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statement_t& operator=(statement_t&& r) = default;
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~statement_t() = default;
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static constexpr size_t _get_static_no_of_parameters()
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{
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return std::tuple_size<parameters_of<statement_t>>::value;
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}
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size_t _get_no_of_parameters() const
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{
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return _get_static_no_of_parameters();
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}
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static constexpr bool _can_be_used_as_table()
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{
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return _policies_t::_can_be_used_as_table();
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}
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template<typename Database>
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auto _run(Database& db) const -> decltype(std::declval<_result_methods_t<statement_t>>()._run(db))
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{
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_run_check::_();
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return _result_methods_t<statement_t>::_run(db);
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}
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template<typename Database>
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auto _prepare(Database& db) const -> decltype(std::declval<_result_methods_t<statement_t>>()._prepare(db))
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{
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_prepare_check::_();
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return _result_methods_t<statement_t>::_prepare(db);
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}
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};
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template<typename Context, typename Database, typename... Policies>
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struct serializer_t<Context, statement_t<Database, Policies...>>
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{
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using P = detail::statement_policies_t<Database, Policies...>;
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using _serialize_check = serialize_check_of<Context, typename Policies::template _base_t<P>::_data_t...>;
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using T = statement_t<Database, Policies...>;
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static Context& _(const T& t, Context& context)
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{
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using swallow = int[];
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(void) swallow{(serialize(static_cast<const typename Policies::template _base_t<P>&>(t)()._data, context), 0)...};
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return context;
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}
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};
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template<typename NameData, typename Tag = tag::is_noop>
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struct statement_name_t
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{
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using _traits = make_traits<no_value_t, Tag>;
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using _recursive_traits = make_recursive_traits<>;
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// Data
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using _data_t = NameData;
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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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// Base template to be inherited by the statement
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template<typename Policies>
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struct _base_t
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{
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using _data_t = NameData;
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_impl_t<Policies> statement_name;
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_impl_t<Policies>& operator()() { return statement_name; }
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const _impl_t<Policies>& operator()() const { return statement_name; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.statement_name)
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{
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return t.statement_name;
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}
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using _consistency_check = consistent_t;
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};
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};
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}
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#endif
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