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mirror of https://github.com/rbock/sqlpp11.git synced 2024-11-16 04:47:18 +08:00
sqlpp11/include/sqlpp11/functions.h
rbock d0d5e94bf1 Added eval function for both strings and expressions.
eval wraps whatever you give to it into a select call, sends it to the
database and returns the value as a result field.
2014-08-18 10:46:24 +02:00

138 lines
4.2 KiB
C++

/*
* Copyright (c) 2013-2014, 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_FUNCTIONS_H
#define SQLPP_FUNCTIONS_H
#include <sqlpp11/parameter.h>
#include <sqlpp11/parameter_list.h>
#include <sqlpp11/column_types.h>
#include <sqlpp11/in.h>
#include <sqlpp11/is_null.h>
#include <sqlpp11/value_type.h>
#include <sqlpp11/exists.h>
#include <sqlpp11/any.h>
#include <sqlpp11/some.h>
#include <sqlpp11/count.h>
#include <sqlpp11/min.h>
#include <sqlpp11/max.h>
#include <sqlpp11/avg.h>
#include <sqlpp11/sum.h>
#include <sqlpp11/verbatim.h> // Csaba Csoma suggests: unsafe_sql instead of verbatim
#include <sqlpp11/verbatim_table.h>
#include <sqlpp11/value_or_null.h>
#include <sqlpp11/eval.h>
namespace sqlpp
{
template<typename T>
auto value(T t) -> wrap_operand_t<T>
{
static_assert(is_wrapped_value_t<wrap_operand_t<T>>::value, "value() is to be called with non-sql-type like int, or string");
return { t };
}
template<typename Expression, typename Db>
auto flatten(const Expression& exp, Db& db) -> verbatim_t<value_type_of<Expression>>
{
static_assert(not make_parameter_list_t<Expression>::size::value, "parameters are not allowed in flattened expressions");
auto context = db.get_serializer_context();
serialize(exp, context);
return { context.str() };
}
template<typename Expression>
auto is_null(Expression e) -> decltype(e.is_null())
{
return e.is_null();
}
template<typename Expression>
auto is_not_null(Expression e) -> decltype(e.is_not_null())
{
return e.is_not_null();
}
template<typename Container>
struct value_list_t // to be used in .in() method
{
using _traits = make_traits<value_type_t<typename Container::value_type>, ::sqlpp::tag::is_expression>;
using _recursive_traits = make_recursive_traits<>;
using _container_t = Container;
value_list_t(_container_t container):
_container(container)
{}
value_list_t(const value_list_t&) = default;
value_list_t(value_list_t&&) = default;
value_list_t& operator=(const value_list_t&) = default;
value_list_t& operator=(value_list_t&&) = default;
~value_list_t() = default;
_container_t _container;
};
template<typename Context, typename Container>
struct serializer_t<Context, value_list_t<Container>>
{
using T = value_list_t<Container>;
static Context& _(const T& t, Context& context)
{
bool first = true;
for (const auto& entry: t._container)
{
if (first)
first = false;
else
context << ',';
serialize(value(entry), context);
}
return context;
}
};
template<typename Container>
auto value_list(Container c) -> value_list_t<Container>
{
static_assert(is_wrapped_value_t<wrap_operand_t<typename Container::value_type>>::value, "value_list() is to be called with a container of non-sql-type like std::vector<int>, or std::list(string)");
return { c };
}
template<typename T>
constexpr const char* get_sql_name(const T&)
{
return T::_name_t::_get_name();
}
}
#endif