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sqlpp11/include/sqlpp11/where.h
Roland Bock 4b4048bd11 Unified interface for where and dynamic_where.
Compatible with previous interface.
Both where and dynamic where can now take a variable amount of
arguments. where() requires at least one argument.
2013-11-16 09:37:38 +01:00

74 lines
2.9 KiB
C++

/*
* Copyright (c) 2013, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SQLPP_WHERE_H
#define SQLPP_WHERE_H
#include <ostream>
#include <sqlpp11/select_fwd.h>
#include <sqlpp11/expression.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/detail/set.h>
#include <sqlpp11/detail/serialize_tuple.h>
#include <sqlpp11/detail/serializable_list.h>
namespace sqlpp
{
template<typename Database, typename... Expr>
struct where_t
{
using _is_where = std::true_type;
using _is_dynamic = typename std::conditional<std::is_same<Database, void>::value, std::false_type, std::true_type>::type;
static_assert(_is_dynamic::value or sizeof...(Expr), "at least one expression argument required in where()");
using _valid_expressions = typename detail::make_set_if<is_expression_t, Expr...>::type;
static_assert(_valid_expressions::size::value == sizeof...(Expr), "at least one argument is not an expression in where()");
template<typename E>
void add(E&& expr)
{
static_assert(is_expression_t<typename std::decay<E>::type>::value, "invalid expression argument in add_where()");
static_assert(_is_dynamic::value, "cannot add expressions to a non-dynamic where()");
_dynamic_expressions.emplace_back(std::forward<E>(expr));
}
template<typename Db>
void serialize(std::ostream& os, Db& db) const
{
if (sizeof...(Expr) == 0 and _dynamic_expressions.empty())
return;
os << " WHERE ";
detail::serialize_tuple(os, db, _expressions, " AND ");
_dynamic_expressions.serialize(os, db, " AND ", true);
}
std::tuple<Expr...> _expressions;
detail::serializable_list<Database> _dynamic_expressions;
};
}
#endif