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sqlpp11/remove.h
2013-08-13 22:43:10 +02:00

123 lines
3.6 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_REMOVE_H
#define SQLPP_REMOVE_H
#include <sstream>
#include <sqlpp11/noop.h>
#include <sqlpp11/using.h>
#include <sqlpp11/where.h>
#include <sqlpp11/type_traits.h>
namespace sqlpp
{
template<
typename Table,
typename Using = noop,
typename Where = noop
>
struct remove_t;
template<
typename Table,
typename Using,
typename Where
>
struct remove_t
{
static_assert(is_noop<Table>::value or is_table_t<Table>::value, "invalid 'Table' argument");
static_assert(is_noop<Using>::value or is_using_t<Using>::value, "invalid 'Using' argument");
static_assert(is_noop<Where>::value or is_where_t<Where>::value, "invalid 'Where' argument");
template<typename... Tab>
using add_using_t = remove_t<Table, using_t<typename std::decay<Tab>::type...>, Where>;
template<typename Expr>
using add_where_t = remove_t<Table, Using, where_t<typename std::decay<Expr>::type>>;
template<typename... Tab>
add_using_t<Tab...> using_(Tab&&... tab)
{
static_assert(std::is_same<Using, noop>::value, "cannot call using() twice");
static_assert(std::is_same<Where, noop>::value, "cannot call using() after where()");
return {
_table,
{{std::forward<Tab>(tab)...}},
_where
};
}
template<typename Expr>
add_where_t<Expr> where(Expr&& where)
{
static_assert(std::is_same<Where, noop>::value, "cannot call where() twice");
return {
_table,
_using,
{std::forward<Expr>(where)},
};
}
template<typename Db>
const remove_t& serialize(std::ostream& os, Db& db) const
{
os << "DELETE FROM ";
_table.serialize(os, db);
_using.serialize(os, db);
_where.serialize(os, db);
return *this;
}
template<typename Db>
remove_t& serialize(std::ostream& os, Db& db)
{
static_cast<const remove_t*>(this)->serialize(os, db);
return *this;
}
template<typename Db>
std::size_t run(Db& db) const
{
std::ostringstream oss;
serialize(oss, db);
return db.remove(oss.str());
}
Table _table;
Using _using;
Where _where;
};
template<typename Table>
constexpr remove_t<typename std::decay<Table>::type> remove_from(Table&& table)
{
return {std::forward<Table>(table)};
}
}
#endif