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
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
|
/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "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.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** 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
** OWNER 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."
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
#include <QtSql>
#include <iostream>
using namespace std;
QString tr(const char *text)
{
return QApplication::translate(text, text);
}
void QSqlDatabase_snippets()
{
{
//! [0]
QSqlDatabase db = QSqlDatabase::addDatabase("QPSQL");
db.setHostName("acidalia");
db.setDatabaseName("customdb");
db.setUserName("mojito");
db.setPassword("J0a1m8");
bool ok = db.open();
//! [0]
Q_UNUSED(ok);
}
{
//! [1]
QSqlDatabase db = QSqlDatabase::database();
//! [1]
}
}
void QSqlField_snippets()
{
#if 0
{
//! [2]
QSqlField field("age", QVariant::Int);
field.setValue(QPixmap()); // WRONG
//! [2]
}
#endif
{
//! [3]
QSqlField field("age", QVariant::Int);
field.setValue(QString("123")); // casts QString to int
//! [3]
}
{
//! [4]
QSqlQuery query;
//! [4] //! [5]
QSqlRecord record = query.record();
//! [5] //! [6]
QSqlField field = record.field("country");
//! [6]
}
}
void doSomething(const QString &)
{
}
void QSqlQuery_snippets()
{
{
// typical loop
//! [7]
QSqlQuery query("SELECT country FROM artist");
while (query.next()) {
QString country = query.value(0).toString();
doSomething(country);
}
//! [7]
}
{
// field index lookup
//! [8]
QSqlQuery query("SELECT * FROM artist");
int fieldNo = query.record().indexOf("country");
while (query.next()) {
QString country = query.value(fieldNo).toString();
doSomething(country);
}
//! [8]
}
{
// named with named
//! [9]
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (:id, :forename, :surname)");
query.bindValue(":id", 1001);
query.bindValue(":forename", "Bart");
query.bindValue(":surname", "Simpson");
query.exec();
//! [9]
}
{
// positional with named
//! [10]
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (:id, :forename, :surname)");
query.bindValue(0, 1001);
query.bindValue(1, "Bart");
query.bindValue(2, "Simpson");
query.exec();
//! [10]
}
{
// positional 1
//! [11]
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (?, ?, ?)");
query.bindValue(0, 1001);
query.bindValue(1, "Bart");
query.bindValue(2, "Simpson");
query.exec();
//! [11]
}
{
// positional 2
//! [12]
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (?, ?, ?)");
query.addBindValue(1001);
query.addBindValue("Bart");
query.addBindValue("Simpson");
query.exec();
//! [12]
}
{
// stored
//! [13]
QSqlQuery query;
query.prepare("CALL AsciiToInt(?, ?)");
query.bindValue(0, "A");
query.bindValue(1, 0, QSql::Out);
query.exec();
int i = query.boundValue(1).toInt(); // i is 65
//! [13]
Q_UNUSED(i);
}
QSqlQuery query;
{
// examine with named binding
//! [14]
QMapIterator<QString, QVariant> i(query.boundValues());
while (i.hasNext()) {
i.next();
cout << i.key().toAscii().data() << ": "
<< i.value().toString().toAscii().data() << endl;
}
//! [14]
}
{
// examine with positional binding
//! [15]
QList<QVariant> list = query.boundValues().values();
for (int i = 0; i < list.size(); ++i)
cout << i << ": " << list.at(i).toString().toAscii().data() << endl;
//! [15]
}
}
void QSqlQueryModel_snippets()
{
{
//! [16]
QSqlQueryModel *model = new QSqlQueryModel;
model->setQuery("SELECT name, salary FROM employee");
model->setHeaderData(0, Qt::Horizontal, tr("Name"));
model->setHeaderData(1, Qt::Horizontal, tr("Salary"));
//! [17]
QTableView *view = new QTableView;
//! [17] //! [18]
view->setModel(model);
//! [18] //! [19]
view->show();
//! [16] //! [19] //! [20]
view->setEditTriggers(QAbstractItemView::NoEditTriggers);
//! [20]
}
//! [21]
QSqlQueryModel model;
model.setQuery("SELECT * FROM employee");
int salary = model.record(4).value("salary").toInt();
//! [21]
Q_UNUSED(salary);
{
//! [22]
int salary = model.data(model.index(4, 2)).toInt();
//! [22]
Q_UNUSED(salary);
}
for (int row = 0; row < model.rowCount(); ++row) {
for (int col = 0; col < model.columnCount(); ++col) {
qDebug() << model.data(model.index(row, col));
}
}
}
class MyModel : public QSqlQueryModel
{
public:
QVariant data(const QModelIndex &item, int role) const;
int m_specialColumnNo;
};
//! [23]
QVariant MyModel::data(const QModelIndex &item, int role) const
{
if (item.column() == m_specialColumnNo) {
// handle column separately
}
return QSqlQueryModel::data(item, role);
}
//! [23]
void QSqlTableModel_snippets()
{
//! [24]
QSqlTableModel *model = new QSqlTableModel(parentObject, database);
model->setTable("employee");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
model->select();
model->removeColumn(0); // don't show the ID
model->setHeaderData(0, Qt::Horizontal, tr("Name"));
model->setHeaderData(1, Qt::Horizontal, tr("Salary"));
QTableView *view = new QTableView;
view->setModel(model);
view->show();
//! [24]
{
//! [25]
QSqlTableModel model;
model.setTable("employee");
QString name = model.record(4).value("name").toString();
//! [25]
}
}
void sql_intro_snippets()
{
{
//! [26]
QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("bigblue");
db.setDatabaseName("flightdb");
db.setUserName("acarlson");
db.setPassword("1uTbSbAs");
bool ok = db.open();
//! [26]
Q_UNUSED(ok);
}
{
//! [27]
QSqlDatabase firstDB = QSqlDatabase::addDatabase("QMYSQL", "first");
QSqlDatabase secondDB = QSqlDatabase::addDatabase("QMYSQL", "second");
//! [27]
}
{
//! [28]
QSqlDatabase defaultDB = QSqlDatabase::database();
//! [28] //! [29]
QSqlDatabase firstDB = QSqlDatabase::database("first");
//! [29] //! [30]
QSqlDatabase secondDB = QSqlDatabase::database("second");
//! [30]
}
{
// SELECT1
//! [31]
QSqlQuery query;
query.exec("SELECT name, salary FROM employee WHERE salary > 50000");
//! [31]
//! [32]
while (query.next()) {
QString name = query.value(0).toString();
int salary = query.value(1).toInt();
qDebug() << name << salary;
}
//! [32]
}
{
// FEATURE
//! [33]
QSqlQuery query;
int numRows;
query.exec("SELECT name, salary FROM employee WHERE salary > 50000");
QSqlDatabase defaultDB = QSqlDatabase::database();
if (defaultDB.driver()->hasFeature(QSqlDriver::QuerySize)) {
numRows = query.size();
} else {
// this can be very slow
query.last();
numRows = query.at() + 1;
}
//! [33]
}
{
// INSERT1
//! [34]
QSqlQuery query;
query.exec("INSERT INTO employee (id, name, salary) "
"VALUES (1001, 'Thad Beaumont', 65000)");
//! [34]
}
{
// NAMED BINDING
//! [35]
QSqlQuery query;
query.prepare("INSERT INTO employee (id, name, salary) "
"VALUES (:id, :name, :salary)");
query.bindValue(":id", 1001);
query.bindValue(":name", "Thad Beaumont");
query.bindValue(":salary", 65000);
query.exec();
//! [35]
}
{
// POSITIONAL BINDING
//! [36]
QSqlQuery query;
query.prepare("INSERT INTO employee (id, name, salary) "
"VALUES (?, ?, ?)");
query.addBindValue(1001);
query.addBindValue("Thad Beaumont");
query.addBindValue(65000);
query.exec();
//! [36]
}
{
// UPDATE1
//! [37]
QSqlQuery query;
query.exec("UPDATE employee SET salary = 70000 WHERE id = 1003");
//! [37]
}
{
// DELETE1
//! [38]
QSqlQuery query;
query.exec("DELETE FROM employee WHERE id = 1007");
//! [38]
}
{
// TRANSACTION
//! [39]
QSqlDatabase::database().transaction();
QSqlQuery query;
query.exec("SELECT id FROM employee WHERE name = 'Torild Halvorsen'");
if (query.next()) {
int employeeId = query.value(0).toInt();
query.exec("INSERT INTO project (id, name, ownerid) "
"VALUES (201, 'Manhattan Project', "
+ QString::number(employeeId) + ')');
}
QSqlDatabase::database().commit();
//! [39]
}
{
// SQLQUERYMODEL1
//! [40]
QSqlQueryModel model;
model.setQuery("SELECT * FROM employee");
for (int i = 0; i < model.rowCount(); ++i) {
int id = model.record(i).value("id").toInt();
QString name = model.record(i).value("name").toString();
qDebug() << id << name;
}
//! [40]
}
{
// SQLTABLEMODEL1
//! [41]
QSqlTableModel model;
model.setTable("employee");
model.setFilter("salary > 50000");
model.setSort(2, Qt::DescendingOrder);
model.select();
for (int i = 0; i < model.rowCount(); ++i) {
QString name = model.record(i).value("name").toString();
int salary = model.record(i).value("salary").toInt();
qDebug() << name << salary;
}
//! [41]
}
{
// SQLTABLEMODEL2
QSqlTableModel model;
model.setTable("employee");
//! [42]
for (int i = 0; i < model.rowCount(); ++i) {
QSqlRecord record = model.record(i);
double salary = record.value("salary").toInt();
salary *= 1.1;
record.setValue("salary", salary);
model.setRecord(i, record);
}
model.submitAll();
//! [42]
// SQLTABLEMODEL3
int row = 1;
int column = 2;
//! [43]
model.setData(model.index(row, column), 75000);
model.submitAll();
//! [43]
// SQLTABLEMODEL4
//! [44]
model.insertRows(row, 1);
model.setData(model.index(row, 0), 1013);
model.setData(model.index(row, 1), "Peter Gordon");
model.setData(model.index(row, 2), 68500);
model.submitAll();
//! [44]
//! [45]
model.removeRows(row, 5);
//! [45] //! [46]
model.submitAll();
//! [46]
}
}
//! [47]
class XyzResult : public QSqlResult
{
public:
XyzResult(const QSqlDriver *driver)
: QSqlResult(driver) {}
~XyzResult() {}
protected:
QVariant data(int /* index */) { return QVariant(); }
bool isNull(int /* index */) { return false; }
bool reset(const QString & /* query */) { return false; }
bool fetch(int /* index */) { return false; }
bool fetchFirst() { return false; }
bool fetchLast() { return false; }
int size() { return 0; }
int numRowsAffected() { return 0; }
QSqlRecord record() const { return QSqlRecord(); }
};
//! [47]
//! [48]
class XyzDriver : public QSqlDriver
{
public:
XyzDriver() {}
~XyzDriver() {}
bool hasFeature(DriverFeature /* feature */) const { return false; }
bool open(const QString & /* db */, const QString & /* user */,
const QString & /* password */, const QString & /* host */,
int /* port */, const QString & /* options */)
{ return false; }
void close() {}
QSqlResult *createResult() const { return new XyzResult(this); }
};
//! [48]
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QSqlDatabase_snippets();
QSqlField_snippets();
QSqlQuery_snippets();
QSqlQueryModel_snippets();
QSqlTableModel_snippets();
XyzDriver driver;
XyzResult result(&driver);
}
|