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101 lines
3.2 KiB
C++
101 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_JOIN_H
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#define SQLPP_JOIN_H
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#include <sqlpp11/type_traits.h>
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namespace sqlpp
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{
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struct inner_join_t
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{
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static constexpr const char* _name = "INNER";
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};
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struct outer_join_t
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{
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static constexpr const char* _name = "OUTER";
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};
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struct left_join_t
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{
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static constexpr const char* _name = "LEFT OUTER";
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};
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struct right_join_t
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{
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static constexpr const char* _name = "RIGHT OUTER";
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};
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template<typename JoinType, typename Lhs, typename Rhs, typename On = noop>
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struct join_t
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{
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static_assert(is_table_t<Lhs>::value, "invalid lhs argument for join()");
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static_assert(is_table_t<Rhs>::value, "invalid rhs argument for join()");
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static_assert(is_noop<On>::value or is_expression_t<On>::value, "invalid on expression in join().on()");
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static_assert(Lhs::_table_set::template is_disjunct_from<typename Rhs::_table_set>::value, "joined tables must not be identical");
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using _is_table = typename std::conditional<is_noop<On>::value,
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tag_no,
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tag_yes>::type;
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using _table_set = typename std::conditional<is_noop<On>::value,
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void,
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typename Lhs::_table_set::template join<typename Rhs::_table_set>::type>::type;
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template<typename Expr>
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using add_on_t = join_t<JoinType, Lhs, Rhs, typename std::decay<Expr>::type>;
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template<typename Expr>
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add_on_t<Expr> on(Expr&& expr)
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{
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return { _lhs, _rhs, std::forward<Expr>(expr) };
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}
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template<typename T>
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join_t<inner_join_t, join_t, typename std::decay<T>::type> join(T&& t)
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{
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return { *this, std::forward<T>(t) };
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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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os << " (";
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_lhs.serialize(os, db);
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os << ") " << JoinType::_name << " JOIN (";
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_rhs.serialize(os, db);
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os << ") ON (";
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_on.serialize(os, db);
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os << ")";
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}
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Lhs _lhs;
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Rhs _rhs;
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On _on;
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};
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}
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#endif
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