缘由
对于Qt的学习我目前了解到的是界面，多线程，网络，数据库操作，文件操作。都是一些基本的，但是必不可少的原子操作。再复杂的更能也是由这些一点一滴的累积起来的。
所以这里就给大家介绍下Qt数据库编程。
我这里介绍两种数据库，MySQL,SQLite3,最常用的数据库。
首先要安装数据库，我之前的博客中有介绍，这里就不赘述了。
源码（经验证）
SQLite3
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("./memory.xdb");
db.open();
cout << "Let's begin......\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 offices (id int primary key,"
"imagefile int,"
"location varchar(20),"
"country varchar(20),"
"description varchar(100))");
query.exec("insert into offices "
"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 offices "
"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 offices "
"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 offices "
"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 offices "
"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 offices "
"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')");
query.exec("select * from offices");
while (query.next()) {
int id = query.value(0).toInt();
int imagefile = query.value(1).toInt();
QString location = query.value(2).toString();
QString country = query.value(3).toString();
QString description = query.value(4).toString();
qDebug() << "id = " <<id<<"\n"
<< "imagefile = "<< imagefile <<"\n"
<< "location = " <<location <<"\n"
<< "country = " << country <<"\n"
<< "description : " << description <<"\n";
}
db.close();
MySQL.
QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("localhost");
db.setDatabaseName("test");
db.setUserName("root");
db.setPassword("ubuntu");
qDebug() << QSqlDatabase::drivers();//查询数据库驱动
bool succ = db.open();
if (succ) {
qDebug("yes\n");
db.exec("SET NAMES ’UTF8’");
QSqlQuery query;
query.exec("select * from teacher");
while (query.next()) {
int id = query.value(0).toInt();
QString name = query.value(1).toString();
//QString address = ANSITOUTF8(query.value(2).toByteArray());
QString address=query.value(2).toString();
QString date = query.value(3).toString();
qDebug() << "id = " <<id<<"\n"
<< "name = "<< name <<"\n"
<< "address = " <<address <<"\n"
<< "date = " << date <<"\n";
} ;
db.close();
cout << "\nOK.\n";
} else {
qDebug("No");
QMessageBox::critical(0,QObject::tr("Error"),db.lastError().text());
}
db.close();
总结：
关于数据库的操作，我就介绍到这里了，不管其他的东西，只是这些简单的数据库操作，掌握后需要了解的就不仅仅是数据库的操作了，是Model/View数据模型的模式了。这个是比较重要的。什么柱状图之类的，都要好好研究，这些好像就是Qt的设计模式了，我比较愚笨，只能了解，深入的知识也没有好好的深入讨论。