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81 lines
3.2 KiB
C++
81 lines
3.2 KiB
C++
/*
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* Copyright (c) 2013, 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_ORDER_BY_H
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#define SQLPP_ORDER_BY_H
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#include <tuple>
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#include <ostream>
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#include <sqlpp11/select_fwd.h>
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#include <sqlpp11/type_traits.h>
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#include <sqlpp11/detail/serialize_tuple.h>
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#include <sqlpp11/detail/serializable.h>
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namespace sqlpp
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{
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template<typename Database,typename... Expr>
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struct order_by_t
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{
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using _is_order_by = std::true_type;
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using _is_dynamic = typename std::conditional<std::is_same<Database, void>::value, std::false_type, std::true_type>::type;
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// check for at least one order expression
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static_assert(_is_dynamic::value or sizeof...(Expr), "at least one sort-order expression required in order_by()");
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// check for duplicate order expressions
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static_assert(not detail::has_duplicates<Expr...>::value, "at least one duplicate argument detected in order_by()");
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// check for invalid order expressions
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using _valid_expressions = typename detail::make_set_if<is_sort_order_t, Expr...>::type;
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static_assert(_valid_expressions::size::value == sizeof...(Expr), "at least one argument is not a sort order expression in order_by()");
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template<typename E>
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void add(E&& expr)
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{
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static_assert(is_sort_order_t<typename std::decay<E>::type>::value, "order_by arguments require to be sort-order expressions");
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_dynamic_expressions.push_back(std::forward<E>(expr));
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}
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template<typename Db>
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void serialize(std::ostream& os, Db& db) const
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{
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static_assert(Db::_supports_order_by, "order by not supported by current database");
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if (sizeof...(Expr) == 0 and _dynamic_expressions.empty())
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return;
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os << " ORDER BY ";
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detail::serialize_tuple(os, db, _expressions, ',');
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_dynamic_expressions.serialize(os, db, sizeof...(Expr) == 0);
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}
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std::tuple<Expr...> _expressions;
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detail::serializable_list<Database> _dynamic_expressions;
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};
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}
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#endif
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