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Add is_equal_or_null(col, some_value_or_null)

This replaces the former implicit tvin logic with an explicit function.
This commit is contained in:
Roland Bock 2021-07-25 15:22:12 +02:00
parent 135db9397b
commit d68744c432
5 changed files with 94 additions and 3 deletions

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@ -47,6 +47,7 @@
#include <sqlpp11/verbatim_table.h> #include <sqlpp11/verbatim_table.h>
#include <sqlpp11/value.h> #include <sqlpp11/value.h>
#include <sqlpp11/value_or_null.h> #include <sqlpp11/value_or_null.h>
#include <sqlpp11/is_equal_to_or_null.h>
#include <sqlpp11/eval.h> #include <sqlpp11/eval.h>
namespace sqlpp namespace sqlpp

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@ -0,0 +1,85 @@
/*
* Copyright (c) 2021, 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 SQLPP11_IS_EQUAL_TO_OR_NULL_H
#define SQLPP11_IS_EQUAL_TO_OR_NULL_H
#include <sqlpp11/value_or_null.h>
namespace sqlpp
{
template <typename Expr, typename ValueType>
struct is_equal_to_or_null_t: public expression_operators<is_equal_to_or_null_t<Expr, ValueType>, boolean>,
public alias_operators<is_equal_to_or_null_t<Expr, ValueType>>
{
using _traits = make_traits<boolean, tag::is_expression>;
using _nodes = detail::type_vector<Expr, value_or_null_t<ValueType>>;
is_equal_to_or_null_t(Expr expr, value_or_null_t<ValueType> value) : _expr(expr), _value(value)
{
}
is_equal_to_or_null_t(const is_equal_to_or_null_t&) = default;
is_equal_to_or_null_t(is_equal_to_or_null_t&&) = default;
is_equal_to_or_null_t& operator=(const is_equal_to_or_null_t&) = default;
is_equal_to_or_null_t& operator=(is_equal_to_or_null_t&&) = default;
~is_equal_to_or_null_t() = default;
Expr _expr;
value_or_null_t<ValueType> _value;
};
template <typename Context, typename Expr, typename ValueType>
struct serializer_t<Context, is_equal_to_or_null_t<Expr, ValueType>>
{
using _serialize_check = consistent_t;
using Operand = is_equal_to_or_null_t<Expr, ValueType>;
static Context& _(const Operand& t, Context& context)
{
if (t._value._is_null)
serialize(t._expr.is_null(), context);
else
serialize(t._expr == t._value, context);
return context;
}
};
template <typename Expr, typename ValueType>
auto is_equal_to_or_null(Expr expr, value_or_null_t<ValueType> value) -> is_equal_to_or_null_t<Expr, ValueType>
{
static_assert(is_expression_t<Expr>::value,
"is_equal_to_or_null() is to be called an expression (e.g. a column) and a value_or_null expression");
static_assert(std::is_same<value_type_of<Expr>, ValueType>::value,
"is_equal_to_or_null() arguments need to have the same value type");
return {expr, value};
}
} // namespace sqlpp
#endif

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@ -78,8 +78,9 @@ namespace sqlpp
static Context& _(const T& t, Context& context) static Context& _(const T& t, Context& context)
{ {
context << "(";
serialize_operand(t._operand, context); serialize_operand(t._operand, context);
context << " IS NOT NULL"; context << " IS NOT NULL)";
return context; return context;
} }
}; };

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@ -78,8 +78,9 @@ namespace sqlpp
static Context& _(const T& t, Context& context) static Context& _(const T& t, Context& context)
{ {
context << "(";
serialize_operand(t._operand, context); serialize_operand(t._operand, context);
context << " IS NULL"; context << " IS NULL)";
return context; return context;
} }
}; };

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@ -63,8 +63,11 @@ int Where(int, char*[])
// Sometimes // Sometimes
compare(__LINE__, where(bar.gamma), " WHERE tab_bar.gamma"); compare(__LINE__, where(bar.gamma), " WHERE tab_bar.gamma");
compare(__LINE__, where(bar.gamma == false), " WHERE (tab_bar.gamma=" + getFalse() + ")"); compare(__LINE__, where(bar.gamma == false), " WHERE (tab_bar.gamma=" + getFalse() + ")");
compare(__LINE__, where(bar.beta.is_null()), " WHERE tab_bar.beta IS NULL"); compare(__LINE__, where(bar.beta.is_null()), " WHERE (tab_bar.beta IS NULL)");
compare(__LINE__, where(bar.beta == "SQL"), " WHERE (tab_bar.beta='SQL')"); compare(__LINE__, where(bar.beta == "SQL"), " WHERE (tab_bar.beta='SQL')");
compare(__LINE__, where(is_equal_to_or_null(bar.beta, ::sqlpp::value_or_null("SQL"))), " WHERE (tab_bar.beta='SQL')");
compare(__LINE__, where(is_equal_to_or_null(bar.beta, ::sqlpp::value_or_null<sqlpp::text>(::sqlpp::null))),
" WHERE (tab_bar.beta IS NULL)");
#if __cplusplus >= 201703L #if __cplusplus >= 201703L
// string_view argument // string_view argument
std::string_view sqlString = "SQL"; std::string_view sqlString = "SQL";