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sqlpp11/include/sqlpp11/from.h

100 lines
3.2 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_FROM_H
#define SQLPP_FROM_H
#include <ostream>
#include <vector>
#include <sqlpp11/select_fwd.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/detail/serializable.h>
#include <sqlpp11/detail/serialize_tuple.h>
namespace sqlpp
{
template<typename... TableOrJoin>
struct from_t
{
using _is_from = std::true_type;
// ensure one argument at least
static_assert(sizeof...(TableOrJoin), "at least one table or join argument required in from()");
// check for duplicate arguments
static_assert(not detail::has_duplicates<TableOrJoin...>::value, "at least one duplicate argument detected in from()");
// check for invalid arguments
using _valid_expressions = typename detail::make_set_if<is_table_t, TableOrJoin...>::type;
static_assert(_valid_expressions::size::value == sizeof...(TableOrJoin), "at least one argument is not an table or join in from()");
// FIXME: Joins contain two tables. This is not being dealt with at the moment
template<typename Db>
void serialize(std::ostream& os, Db& db) const
{
os << " FROM ";
detail::serialize_tuple(os, db, _tables, ',');
}
std::tuple<TableOrJoin...> _tables;
};
template<typename Db>
struct dynamic_from_t
{
using _is_from = std::true_type;
using _is_dynamic = std::true_type;
template<typename Table>
void add(Table&& table)
{
static_assert(is_table_t<typename std::decay<Table>::type>::value, "from arguments require to be tables or joins");
_dynamic_tables.push_back(std::forward<Table>(table));
}
void serialize(std::ostream& os, Db& db) const
{
if (_dynamic_tables.empty())
return;
os << " FROM ";
bool first = true;
for (const auto& table : _dynamic_tables)
{
if (not first)
os << ',';
table.serialize(os, db);
first = false;
}
}
std::vector<detail::serializable_t<Db>> _dynamic_tables;
};
}
#endif