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Use potential outer table dependencies in pseudo tables

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The dependency indicates whether a column of a pseudo table can be null.
This commit is contained in:
rbock 2014-07-24 09:29:50 +02:00
parent b73133d47a
commit 37a550a489
3 changed files with 25 additions and 5 deletions
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17
include/sqlpp11/detail/type_set.h
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@ -211,6 +211,23 @@ namespace sqlpp
template<typename Minuend, typename Subtrahend>
using make_difference_set_t = typename make_difference_set<Minuend, Subtrahend>::type;
template<typename Lhs, typename Rhs>
struct make_intersect_set
{
static_assert(::sqlpp::wrong_t<Lhs, Rhs>::value, "invalid argument for intersect set");
};
template<typename... LhsElements, typename... RhsElements>
struct make_intersect_set<type_set<LhsElements...>, type_set<RhsElements...>>
{
template<typename E>
using is_in_both = is_element_of<E, make_type_set_t<LhsElements..., RhsElements...>>;
using type = typename make_type_set_if<is_in_both, LhsElements...>::type;
};
template<typename Lhs, typename Rhs>
using make_intersect_set_t = typename make_intersect_set<Lhs, Rhs>::type;
template<template<typename> class Transformation, typename T>
struct transform_set

1
include/sqlpp11/field.h
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@ -48,6 +48,7 @@ namespace sqlpp
namespace detail
{
#warning: Need to transport the "can be null" information via field_t to result_entry structs
template<typename NamedExpr>
struct make_field_t_impl
{

10
include/sqlpp11/select_pseudo_table.h
View File

@ -32,16 +32,18 @@
namespace sqlpp
{
// provide type information for sub-selects that are used as named expressions or tables
template<typename NamedExpr>
template<typename Select, typename NamedExpr>
struct select_column_spec_t
{
#warning use Select here to determine if a column relates to a outer join table
using _name_t = typename NamedExpr::_name_t;
static constexpr bool _can_be_null = can_be_null_t<NamedExpr>::value;
static constexpr bool _depends_on_outer_table = detail::make_intersect_set_t<required_tables_of<NamedExpr>, typename Select::_used_outer_tables>::size::value > 0;
using _traits = make_traits<value_type_of<NamedExpr>,
tag::must_not_insert,
tag::must_not_update,
typename std::conditional<can_be_null_t<NamedExpr>::value, tag::can_be_null, void>::type
typename std::conditional<_can_be_null or _depends_on_outer_table, tag::can_be_null, void>::type
>;
};
@ -51,7 +53,7 @@ namespace sqlpp
>
struct select_pseudo_table_t: public sqlpp::table_t<select_pseudo_table_t<
Select,
NamedExpr...>, select_column_spec_t<NamedExpr>...>
NamedExpr...>, select_column_spec_t<Select, NamedExpr>...>
{
using _traits = make_traits<no_value_t, tag::table, tag::pseudo_table>;
using _recursive_traits = make_recursive_traits<>;