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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
#pragma once
#include <database/engine.hpp>
#include <database/table.hpp>
#include <database/database.hpp>
#include <database/statement.hpp>
#include <utils/datetime.hpp>
#include <database/query.hpp>
#include <database/row.hpp>
#include <utils/optional_bool.hpp>
#include <vector>
#include <string>
using namespace std::string_literals;
template <typename T>
typename std::enable_if<std::is_integral<T>::value, std::int64_t>::type
extract_row_value(Statement& statement, const int i)
{
return statement.get_column_int64(i);
}
template <typename T>
typename std::enable_if<std::is_same<std::string, T>::value, T>::type
extract_row_value(Statement& statement, const int i)
{
return statement.get_column_text(i);
}
template <typename T>
typename std::enable_if<std::is_same<OptionalBool, T>::value, T>::type
extract_row_value(Statement& statement, const int i)
{
const auto integer = statement.get_column_int(i);
OptionalBool result;
if (integer > 0)
result.set_value(true);
else if (integer < 0)
result.set_value(false);
return result;
}
template <typename T>
typename std::enable_if<std::is_same<DateTime, T>::value, T>::type
extract_row_value(Statement& statement, const int i)
{
const std::string timestamp = statement.get_column_text(i);
return {timestamp};
}
template <std::size_t N=0, typename... T>
typename std::enable_if<N < sizeof...(T), void>::type
extract_row_values(Row<T...>& row, Statement& statement)
{
using ColumnType = typename std::remove_reference<decltype(std::get<N>(row.columns))>::type;
auto&& column = std::get<N>(row.columns);
column.value = static_cast<decltype(column.value)>(extract_row_value<typename ColumnType::real_type>(statement, N));
extract_row_values<N+1>(row, statement);
}
template <std::size_t N=0, typename... T>
typename std::enable_if<N == sizeof...(T), void>::type
extract_row_values(Row<T...>&, Statement&)
{}
template <typename ColumnType>
std::string before_column()
{
return {};
}
template <typename ColumnType>
std::string after_column()
{
return {};
}
template <>
std::string before_column<Database::Date>();
template <>
std::string after_column<Database::Date>();
template <typename... T>
struct SelectQuery: public Query
{
SelectQuery(std::string table_name):
Query("SELECT"),
table_name(table_name)
{
this->insert_col_name();
this->body += " from " + this->table_name;
}
template <std::size_t N=0>
typename std::enable_if<N < sizeof...(T), void>::type
insert_col_name()
{
using ColumnsType = std::tuple<T...>;
using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnsType>()))>::type;
this->body += " ";
this->body += before_column<ColumnType>() + ColumnType::name + after_column<ColumnType>();
if (N < (sizeof...(T) - 1))
this->body += ", ";
this->insert_col_name<N+1>();
}
template <std::size_t N=0>
typename std::enable_if<N == sizeof...(T), void>::type
insert_col_name()
{}
SelectQuery& where()
{
this->body += " WHERE ";
return *this;
};
SelectQuery& order_by()
{
this->body += " ORDER BY ";
return *this;
}
SelectQuery& limit()
{
this->body += " LIMIT ";
return *this;
}
auto execute(DatabaseEngine& db)
{
std::vector<Row<T...>> rows;
#ifdef DEBUG_SQL_QUERIES
const auto timer = this->log_and_time();
#endif
auto statement = db.prepare(this->body);
if (!statement)
return rows;
statement->bind(std::move(this->params));
while (statement->step() == StepResult::Row)
{
Row<T...> row(this->table_name);
extract_row_values(row, *statement);
rows.push_back(row);
}
return rows;
}
const std::string table_name;
};
template <typename... T>
auto select(const Table<T...> table)
{
SelectQuery<T...> query(table.name);
return query;
}
|
