1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
// file : odb/query.hxx
// copyright : Copyright (c) 2009-2017 Code Synthesis Tools CC
// license : GNU GPL v2; see accompanying LICENSE file
#ifndef ODB_QUERY_HXX
#define ODB_QUERY_HXX
#include <odb/pre.hxx>
#include <odb/forward.hxx>
#include <odb/traits.hxx>
namespace odb
{
// Table alias for type T and tag Tag.
//
// The alias_traits interface consists of two things: the table_name
// static variable containing the name and, in case of a derived type
// in a polymorphic hierarchy, the base_traits typedef. Note that the
// same interface is exposed by object_traits, which is used when
// we need straight tables instead of aliases.
//
//
template <typename T, database_id DB, typename Tag>
struct alias_traits;
template <typename T, database_id DB>
struct query_columns_base;
template <typename T, database_id DB, typename A>
struct query_columns;
template <typename T, database_id DB, typename A>
struct pointer_query_columns;
// Object pointer syntax wrapper.
//
template <typename T>
struct query_pointer
{
query_pointer ()
{
// For some reason GCC needs this dummy c-tor if we make a static
// data member of this type const.
}
T*
operator-> () const
{
return 0; // All members in T are static.
}
};
// Query parameter decay traits.
//
template <typename T>
struct decay_traits
{
typedef const T& type;
static type
instance ();
};
template <typename T, std::size_t N>
struct decay_traits<T[N]>
{
typedef const T* type;
// Use the pointer comparability as a proxy for data comparability.
// Note that it is stricter than using element comparability (i.e.,
// one can compare int to char but not int* to char*).
//
static type
instance ();
};
// VC9 cannot handle certain cases of non-type arguments with default
// values in template functions (e.g., database::query()). As a result,
// we have to use the impl trick below instead of simply having kind
// as a second template argument with a default value.
//
template <typename T, database_id DB, class_kind kind>
struct query_selector_impl;
template <typename T, database_id DB>
struct query_selector_impl<T, DB, class_object>
{
typedef typename object_traits_impl<T, DB>::query_base_type base_type;
typedef
query_columns<T, DB, access::object_traits_impl<T, DB> >
columns_type;
};
template <typename T, database_id DB>
struct query_selector_impl<T, DB, class_view>
{
typedef typename view_traits_impl<T, DB>::query_base_type base_type;
typedef typename view_traits_impl<T, DB>::query_columns columns_type;
};
template <typename T, database_id DB>
struct query_selector: query_selector_impl<T, DB, class_traits<T>::kind>
{
};
template <typename T,
typename B = typename query_selector<T, id_common>::base_type>
class query;
namespace core
{
using odb::query;
}
}
#include <odb/post.hxx>
#endif // ODB_QUERY_HXX
|