在qt中操作sqlite

昨天师弟来问我qt中如何操作sqlite，我不知道，查了一下，和一般的数据库操作流程差不多，写了个测试的小例子。核心的代码如下：

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("haha.sqlite");
if (!db.open()) {
QMessageBox::critical(0, qApp->tr("Cannot open database"),
qApp->tr("Unable to establish a database connection.\n"
"This example needs SQLite support. Please read "
"the Qt SQL driver documentation for information how "
"to build it.\n\n"
"Click Cancel to exit."), QMessageBox::Cancel);
return;
}
ui.label->setText("Sqlite is connected!\n");

QSqlQuery query;
query.exec("create table person (id int primary key, "
"firstname varchar(20), lastname varchar(20))");
query.exec("insert into person values(101, 'Danny', 'Young')");
query.exec("insert into person values(102, 'Christine', 'Holand')");
query.exec("insert into person values(103, 'Lars', 'Gordon')");
query.exec("insert into person values(104, 'Roberto', 'Robitaille')");
query.exec("insert into person values(105, 'Maria', 'Papadopoulos')");

query.exec("create table trolltechoffice (id int primary key,"
"imagefile int,"
"location varchar(20),"
"country varchar(20),"
"description varchar(100))");
query.exec("insert into trolltechoffice "
"values(0, 0, 'Oslo', 'Norway',"
"'Oslo is home to more than 500 000 citizens and has a "
"lot to offer.It has been called \"The city with the big "
"heart\" and this is a nickname we are happy to live up to.')");
query.exec("insert into trolltechoffice "
"values(1, 1, 'Brisbane', 'Australia',"
"'Brisbane is the capital of Queensland, the Sunshine State, "
"where it is beautiful one day, perfect the next. "
"Brisbane is Australia''s 3rd largest city, being home "
"to almost 2 million people.')");
query.exec("insert into trolltechoffice "
"values(2, 2, 'Redwood City', 'US',"
"'You find Redwood City in the heart of the Bay Area "
"just north of Silicon Valley. The largest nearby city is "
"San Jose which is the third largest city in California "
"and the 10th largest in the US.')");
query.exec("insert into trolltechoffice "
"values(3, 3, 'Berlin', 'Germany',"
"'Berlin, the capital of Germany is dynamic, cosmopolitan "
"and creative, allowing for every kind of lifestyle. "
"East meets West in the metropolis at the heart of a "
"changing Europe.')");
query.exec("insert into trolltechoffice "
"values(4, 4, 'Munich', 'Germany',"
"'Several technology companies are represented in Munich, "
"and the city is often called the \"Bavarian Silicon Valley\". "
"The exciting city is also filled with culture, "
"art and music. ')");
query.exec("insert into trolltechoffice "
"values(5, 5, 'Beijing', 'China',"
"'Beijing as a capital city has more than 3000 years of "
"history. Today the city counts 12 million citizens, and "
"is the political, economic and cultural centre of China.')");

query.exec("create table images (locationid int, file varchar(20))");
query.exec("insert into images values(0, 'images/oslo.png')");
query.exec("insert into images values(1, 'images/brisbane.png')");
query.exec("insert into images values(2, 'images/redwood.png')");
query.exec("insert into images values(3, 'images/berlin.png')");
query.exec("insert into images values(4, 'images/munich.png')");
query.exec("insert into images values(5, 'images/beijing.png')");

ui.label->setText(ui.label->text()+"query is done!\n");
db.close();
ui.label->setText(ui.label->text()+"db is closed!\n");
// reopen db
if (!db.open()) {
QMessageBox::critical(0, qApp->tr("Cannot open database"),
qApp->tr("Unable to establish a database connection.\n"
"This example needs SQLite support. Please read "
"the Qt SQL driver documentation for information how "
"to build it.\n\n"
"Click Cancel to exit."), QMessageBox::Cancel);
return;
}
ui.label->setText(ui.label->text()+"db is reopened!\n");
query.exec("SELECT firstname, lastname FROM person WHERE id > 102");
while (query.next()) {
QString firstname = query.value(0).toString();
QString lastname = query.value(1).toString();
ui.label->setText(ui.label->text()+"firstname:"+firstname+",lastname:"
+lastname+"\n");
}
db.close();
ui.label->setText(ui.label->text()+"db is closed again!\n");
return;