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sqlpp11/include/sqlpp11/column.h

127 lines
4.2 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_COLUMN_H
#define SQLPP_COLUMN_H
#include <sqlpp11/alias.h>
#include <sqlpp11/column_fwd.h>
#include <sqlpp11/default_value.h>
#include <sqlpp11/null.h>
#include <sqlpp11/sort_order.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/vendor/assignment.h>
#include <sqlpp11/vendor/expression.h>
#include <sqlpp11/vendor/interpreter.h>
#include <sqlpp11/vendor/wrong.h>
#include <sqlpp11/detail/type_set.h>
namespace sqlpp
{
template<typename Table, typename ColumnSpec>
struct column_t: public ColumnSpec::_value_type::template operators<column_t<Table, ColumnSpec>>
{
using _is_column = std::true_type;
using _spec_t = ColumnSpec;
using _table = Table;
using _table_set = detail::type_set<_table>;
using _column_type = typename ColumnSpec::_column_type;
struct _value_type: ColumnSpec::_value_type
{
using _is_expression = std::true_type;
using _is_named_expression = std::true_type;
using _is_alias = std::false_type;
};
using _name_t = typename ColumnSpec::_name_t;
column_t() = default;
column_t(const column_t&) = default;
column_t(column_t&&) = default;
column_t& operator=(const column_t&) = default;
column_t& operator=(column_t&&) = default;
~column_t() = default;
static constexpr const char* _get_name()
{
return _name_t::_get_name();
}
template<typename alias_provider>
expression_alias_t<column_t, alias_provider> as(const alias_provider&) const
{
return { *this };
}
template<typename T>
auto operator =(T t) const
-> typename std::enable_if<_value_type::template _constraint<typename vendor::wrap_operand<T>::type>::value and not std::is_same<column_t, T>::value,
vendor::assignment_t<column_t, typename vendor::wrap_operand<T>::type>>::type
{
return { *this, {t} };
}
template<typename T>
auto operator =(T t) const
-> typename std::enable_if<not(_value_type::template _constraint<typename vendor::wrap_operand<T>::type>::value and not std::is_same<column_t, T>::value),
vendor::assignment_t<column_t, typename vendor::wrap_operand<T>::type>>::type
{
static_assert(sqlpp::vendor::wrong_t<T>::value, "invalid assignment operand");
}
auto operator =(sqlpp::null_t) const
->vendor::assignment_t<column_t, sqlpp::null_t>
{
static_assert(can_be_null_t<column_t>::value, "column cannot be null");
return { *this, {} };
}
auto operator =(sqlpp::default_value_t) const
->vendor::assignment_t<column_t, sqlpp::default_value_t>
{
return { *this, {} };
}
};
namespace vendor
{
template<typename Context, typename... Args>
struct interpreter_t<Context, column_t<Args...>>
{
using T = column_t<Args...>;
static Context& _(const T& t, Context& context)
{
context << T::_table::_name_t::_get_name() << '.' << T::_name_t::_get_name();
return context;
}
};
}
}
#endif