mirror of
https://github.com/rbock/sqlpp11.git
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284 lines
8.7 KiB
C++
284 lines
8.7 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_WHERE_H
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#define SQLPP_WHERE_H
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#include <sqlpp11/type_traits.h>
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#include <sqlpp11/parameter_list.h>
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#include <sqlpp11/expression.h>
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#include <sqlpp11/interpret_tuple.h>
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#include <sqlpp11/interpretable_list.h>
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#include <sqlpp11/detail/logic.h>
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namespace sqlpp
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{
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// WHERE DATA
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template<typename Database, typename... Expressions>
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struct where_data_t
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{
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where_data_t(Expressions... expressions):
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_expressions(expressions...)
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{}
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where_data_t(const where_data_t&) = default;
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where_data_t(where_data_t&&) = default;
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where_data_t& operator=(const where_data_t&) = default;
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where_data_t& operator=(where_data_t&&) = default;
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~where_data_t() = default;
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std::tuple<Expressions...> _expressions;
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interpretable_list_t<Database> _dynamic_expressions;
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};
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// WHERE(EXPR)
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template<typename Database, typename... Expressions>
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struct where_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_where>;
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using _recursive_traits = make_recursive_traits<Expressions...>;
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using _is_dynamic = is_database<Database>;
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static_assert(_is_dynamic::value or sizeof...(Expressions), "at least one expression argument required in where()");
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static_assert(sqlpp::detail::none_t<is_assignment_t<Expressions>::value...>::value, "at least one argument is an assignment in where()");
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static_assert(sqlpp::detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not valid expression in where()");
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// Data
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using _data_t = where_data_t<Database, Expressions...>;
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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 Expression>
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void add_ntc(Expression expression)
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{
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add<Expression, std::false_type>(expression);
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}
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template<typename Expression, typename TableCheckRequired = std::true_type>
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void add(Expression expression)
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{
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static_assert(_is_dynamic::value, "where::add() can only be called for dynamic_where");
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static_assert(is_expression_t<Expression>::value, "invalid expression argument in where::add()");
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static_assert(not TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in where::add()");
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using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_expression_t<Expression>::value>;
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_add_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
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}
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private:
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template<typename Expression>
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void _add_impl(Expression expression, const std::true_type&)
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{
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return _data._dynamic_expressions.emplace_back(expression);
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}
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template<typename Expression>
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void _add_impl(Expression expression, const std::false_type&);
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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 = where_data_t<Database, Expressions...>;
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_impl_t<Policies> where;
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_impl_t<Policies>& operator()() { return where; }
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const _impl_t<Policies>& operator()() const { return where; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.where)
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{
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return t.where;
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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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template<>
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struct where_data_t<void, bool>
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{
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bool _condition;
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};
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// WHERE(BOOL)
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template<>
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struct where_t<void, bool>
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_where>;
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using _recursive_traits = make_recursive_traits<>;
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// Data
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using _data_t = where_data_t<void, bool>;
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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 = where_data_t<void, bool>;
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_impl_t<Policies> where;
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_impl_t<Policies>& operator()() { return where; }
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const _impl_t<Policies>& operator()() const { return where; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.where)
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{
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return t.where;
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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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// NO WHERE YET
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template<bool WhereRequired>
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struct no_where_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_where>;
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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_where;
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_impl_t<Policies>& operator()() { return no_where; }
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const _impl_t<Policies>& operator()() const { return no_where; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.no_where)
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{
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return t.no_where;
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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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using _database_t = typename Policies::_database_t;
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template<typename T>
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using _new_statement_t = new_statement<Policies, no_where_t, T>;
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static void _check_consistency()
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{
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static constexpr bool _tables_provided = (Policies::_all_provided_tables::size::value > 0);
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static constexpr bool _required = WhereRequired and _tables_provided;
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static_assert(not _required, "where expression required, e.g. where(true)");
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}
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template<typename... Args>
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auto where(Args... args)
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-> _new_statement_t<where_t<void, Args...>>
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{
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return { *static_cast<typename Policies::_statement_t*>(this), where_data_t<void, Args...>{args...} };
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}
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template<typename... Args>
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auto dynamic_where(Args... args)
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-> _new_statement_t<where_t<_database_t, Args...>>
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{
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static_assert(not std::is_same<_database_t, void>::value, "dynamic_where must not be called in a static statement");
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return { *static_cast<typename Policies::_statement_t*>(this), where_data_t<_database_t, Args...>{args...} };
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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, typename... Expressions>
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struct serializer_t<Context, where_data_t<Database, Expressions...>>
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{
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using T = where_data_t<Database, Expressions...>;
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static Context& _(const T& t, Context& context)
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{
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if (sizeof...(Expressions) == 0 and t._dynamic_expressions.empty())
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return context;
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context << " WHERE ";
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interpret_tuple(t._expressions, " AND ", context);
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if (sizeof...(Expressions) and not t._dynamic_expressions.empty())
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context << " AND ";
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interpret_list(t._dynamic_expressions, " AND ", context);
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return context;
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}
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};
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template<typename Context>
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struct serializer_t<Context, where_data_t<void, bool>>
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{
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using T = where_data_t<void, bool>;
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static Context& _(const T& t, Context& context)
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{
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if (not t._condition)
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context << " WHERE NULL";
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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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