MySQL++ Reference Manual

MySQL++: insertpolicy.h Source File

MySQL++ 3.3.0

insertpolicy.h
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32 /***********************************************************************
33 Copyright © 2008-2009 by AboveNet, Inc., and © 2009 by Educational
34 Technology Resources, Inc. Others may also hold copyrights on code
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36 distribution for details.
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38 This file is part of MySQL++.
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41 under the terms of the GNU Lesser General Public License as published
42 by the Free Software Foundation; either version 2.1 of the License, or
43 (at your option) any later version.
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46 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
47 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
48 License for more details.
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50 You should have received a copy of the GNU Lesser General Public
51 License along with MySQL++; if not, write to the Free Software
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54 ***********************************************************************/
55
56 #if !defined(MYSQLPP_INSERTPOLICY_H)
57 #define MYSQLPP_INSERTPOLICY_H
58
59 // Only allow these templates to be defined if they're being bodily
60 // included into class Query's definition. They're in this separate
61 // file only for claity, so they don't get lost among the other
62 // definitions in class Query. Without this, Doxygen will pick them
63 // up and treat them as a) outside namespace mysqlpp; and b) not member
64 // templates of class Query. We also don't want end-users of the
65 // library to #include this file in their own code; these templates
66 // should only be used as mysqlpp::Query::*.
67 #if defined(MYSQLPP_DEFINE_INSERT_POLICY_TEMPLATES)
68
69
76 template <class AccessController = Transaction>
77 class MYSQLPP_EXPORT RowCountInsertPolicy
78 {
79 public:
81 RowCountInsertPolicy(unsigned int rows) :
82 cur_rows_(0),
83 max_rows_(rows)
84 {
85 }
86
88 ~RowCountInsertPolicy() { }
89
94 template <class RowT>
95 bool can_add(int, const RowT&)
96 {
97 if (++cur_rows_ > max_rows_) {
98 cur_rows_ = 0;
99 return false;
100 }
101 else {
102 return true;
103 }
104 }
105
107 typedef AccessController access_controller;
108
109 private:
110 unsigned int cur_rows_;
111 unsigned const int max_rows_;
112 };
113
114
122 template <class AccessController = Transaction>
123 class MYSQLPP_EXPORT SizeThresholdInsertPolicy
124 {
125 public:
127 SizeThresholdInsertPolicy(int size) :
128 size_(size)
129 {
130 }
131
133 ~SizeThresholdInsertPolicy() { }
134
142 template <class RowT>
143 bool can_add(int size, const RowT& object) const
144 {
145 (void)object; // we don't use this, but other policies do
146 return (size < size_);
147 }
148
150 typedef AccessController access_controller;
151
152 private:
153 int size_;
154 };
155
156
164 template <class AccessController = Transaction>
165 class MYSQLPP_EXPORT MaxPacketInsertPolicy
166 {
167 public:
173 MaxPacketInsertPolicy(Connection* con, int size) :
174 conn_(con), size_(size)
175 {
176 }
177
186 MaxPacketInsertPolicy(int size) :
187 conn_(0), size_(size)
188 {
189 }
190
192 ~MaxPacketInsertPolicy() { }
193
201 template <class RowT>
202 bool can_add(int size, const RowT& object) const
203 {
204 if (size < size_) {
205 // Haven't hit size threshold yet, so see if this next
206 // item pushes it over the line.
207 SQLStream s(conn_);
208 s << ",(" << object.value_list() << ")";
209 return (size_ - size) >= static_cast<int>(s.str().size());
210 }
211 else {
212 // Already too much in query buffer!
213 return false;
214 }
215 }
216
218 typedef AccessController access_controller;
219
220 private:
221 Connection* conn_;
222 int size_;
223 };
224
225 #endif // defined(MYSQLPP_DEFINE_INSERT_POLICY_TEMPLATES)
226
227 #endif // !defined(MYSQLPP_INSERTPOLICY_H)
228