qt4 数据库操作---------tableView

//connection.h
#ifndef CONNECTION_H
#define CONNECTION_H
#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlQuery>

static bool createConnection()
{
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
// db.setDatabaseName(":memory:");
db.setDatabaseName("/test1.db");
if (!db.open()) {
QMessageBox::critical(0, qApp->tr("Cannot open database"),
qApp->tr("Unable to establish a database connection."
), QMessageBox::Cancel);
return false;
}

QSqlQuery query;
query.exec("create table student (id int primary key, name varchar(20))");
//创建表student，如果student表已经存在则无动作
query.exec("insert into student values(0, 'first')");
query.exec("insert into student values(1, 'second')");
query.exec("insert into student values(2, 'third')");
query.exec("insert into student values(3, 'fourth')");
query.exec("insert into student values(4, 'fifth')");
return true;
}
#endif // CONNECTION_H

//main.cpp
#include <QtGui/QApplication>
#include "mainwindow.h"
#include"connection.h"
#include<QDebug>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
if (!createConnection())
return 1;

MainWindow w;
w.show();

return a.exec();
}

//mainwindow.cpp
void MainWindow::on_pushButton_clicked()
{
QSqlQuery query;
query.exec("select * from student");
QString str;
while(query.next())
{
qDebug() << query.value(0).toInt() << query.value(1).toString();
str=str+"\n"+query.value(1).toString();
ui->textEdit->setText(str);
}

}

void MainWindow::on_pushButton_2_clicked()
{
QSqlQuery query;
query.exec("select * from student");
qDebug() << "exec next() :";
if(query.next())
//开始就先执行一次next()函数，那么query指向结果集的第一条记录
{
int rowNum = query.at();
//获取query所指向的记录在结果集中的编号
int columnNum = query.record().count();
//获取每条记录中属性（即列）的个数
int fieldNo = query.record().indexOf("name");
//获取"name"属性所在列的编号，列从左向右编号，最左边的编号为0
int id = query.value(0).toInt();
//获取id属性的值，并转换为int型
QString name = query.value(fieldNo).toString();
//获取name属性的值
qDebug() << "rowNum is : " << rowNum //将结果输出
<< " id is : " << id
<< " name is : " << name
<< " columnNum is : " << columnNum;
}
qDebug() << "exec seek(2) :";
if(query.seek(2))
//定位到结果集中编号为2的记录，即第三条记录，因为第一条记录的编号为0
{
qDebug() << "rowNum is : " << query.at()
<< " id is : " << query.value(0).toInt()
<< " name is : " << query.value(1).toString();
}
qDebug() << "exec last() :";
if(query.last())
//定位到结果集中最后一条记录
{
qDebug() << "rowNum is : " << query.at()
<< " id is : " << query.value(0).toInt()
<< " name is : " << query.value(1).toString();
}
}

当数据库已open，可进行如下操作

创建表

query.exec("create table student (id int primary key, name varchar(20))");
//创建表student，如果student表已经存在则无动作
//有两个字段，id(兼任主键)和name

添加记录

//直接添加
query.exec("insert into student values(1, 'second')");
//在表中增加一条主键即id是1的记录,name字段是"second"
//如果id=1的记录已经存在，则无动作

//使用变量添加
query.prepare("insert into student values (?, ?)");
query.bindValue(0, i);
query.bindValue(1, "sixth");
query.exec();

//或
query.prepare("insert into student (id, name) values (:id, :name)");
query.bindValue(0, i);
query.bindValue(1, "sixth");
query.exec();

//或
query.prepare("insert into student (id, name) values (:id, :name)");
query.addBindValue(i);
query.addBindValue("sixth");
query.exec();

删除记录

query.exec("delete from student where id = 1");

查询记录

//直接查询
query.exec("select name from student where id = 1");
query.exec("select name from student ");
query.exec("select * from student ");

//使用变量
query.prepare("select name from student where id = ?");
int id = ui->spinBox->value(); //从界面获取id的值
query.addBindValue(id); //将id值进行绑定
query.exec();

更新记录

//使用变量
QSqlQuery query;
query.prepare("update student set name = ? where id = ?");
query.addBindValue(name);
query.addBindValue(studentId);
query.exec();

http://www.yafeilinux.com/?p=82
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二十五、Qt数据库（五）QSqlQueryModel

二十六、Qt数据库（六）QSqlTableModel

二十七、Qt数据库（七）QSqlRelationalTableModel

//mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QtGui>
#include <QSqlQuery>
#include <QtDebug>
#include<QSqlRecord>
#include <QModelIndex>
#include<QSqlQueryModel>
#include "mysqlquerymodel.h"
#include <QTableView>
#include <QSqlRelationalDelegate>
#include<QSqlError>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
/*
model = new QSqlTableModel(this);
model->setTable("student");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
model->select(); //选取整个表的所有行
// model->removeColumn(0); //不显示name属性列,如果这时添加记录，则该属性的值添加不上
ui->tableView->setModel(model);
//ui->tableView->setEditTriggers(QAbstractItemView::NoEditTriggers);   //使其不可编
*/

model = new QSqlRelationalTableModel(this);
model->setEditStrategy(QSqlTableModel::OnFieldChange); //属性变化时写入数据库
model->setTable("student");
model->setRelation(2,QSqlRelation("course","id","name"));
//将student表的第三个属性设为course表的id属性的外键，并将其显示为course表的name属性的值
model->setHeaderData(0, Qt::Horizontal, QObject::tr("ID"));
model->setHeaderData(1, Qt::Horizontal, QObject::tr("Name"));
model->setHeaderData(2, Qt::Horizontal, QObject::tr("Course"));
model->select();
ui->tableView->setModel(model);
ui->tableView->setItemDelegate(new QSqlRelationalDelegate(ui->tableView));

}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::on_pushButton_clicked()
{
QSqlQuery query;
query.exec("select * from student");
QString str;
while(query.next())
{
qDebug() << query.value(0).toInt() << query.value(1).toString();
str=str+"\n"+query.value(1).toString();
// ui->lineEdit->setText(str);
//ui->textEdit->setText(str);
}

}

void MainWindow::on_pushButton_2_clicked()
{
QSqlQuery query;
query.exec("select * from student");
qDebug() << "exec next() :";
if(query.next())
//开始就先执行一次next()函数，那么query指向结果集的第一条记录
{
int rowNum = query.at();
//获取query所指向的记录在结果集中的编号
int columnNum = query.record().count();
//获取每条记录中属性（即列）的个数
int fieldNo = query.record().indexOf("name");
//获取"name"属性所在列的编号，列从左向右编号，最左边的编号为0
int id = query.value(0).toInt();
//获取id属性的值，并转换为int型
QString name = query.value(fieldNo).toString();
//获取name属性的值
qDebug() << "rowNum is : " << rowNum //将结果输出
<< " id is : " << id
<< " name is : " << name
<< " columnNum is : " << columnNum;
}
qDebug() << "exec seek(2) :";
if(query.seek(2))
//定位到结果集中编号为2的记录，即第三条记录，因为第一条记录的编号为0
{
qDebug() << "rowNum is : " << query.at()
<< " id is : " << query.value(0).toInt()
<< " name is : " << query.value(1).toString();
}
qDebug() << "exec last() :";
if(query.last())
//定位到结果集中最后一条记录
{
qDebug() << "rowNum is : " << query.at()
<< " id is : " << query.value(0).toInt()
<< " name is : " << query.value(1).toString();
}
}
void MainWindow::on_pushButton_3_clicked()
{
QSqlQuery query;

int i=210;
while(i--){
query.prepare("insert into student values (?, ?)");
query.bindValue(0, i);
query.bindValue(1, "sixth");
query.exec();

}

//下面输出最后一条记录
query.exec("select * from student");
query.last();
int id = query.value(0).toInt();
QString name = query.value(1).toString();
qDebug() << id << name;
}

void MainWindow::on_pushButton_4_clicked()
{         //  QSqlQuery query;
// query.exec("insert into student values(69, '768')");
QSqlQuery query;
query.prepare("select name from student where id = ?");
int id = ui->spinBox->value(); //从界面获取id的值
query.addBindValue(id); //将id值进行绑定
query.exec();
query.next(); //指向第一条记录
qDebug() << query.value(0).toString();

}

void MainWindow::on_pushButton_5_clicked()
{
QSqlQueryModel *model = new QSqlQueryModel;
model->setQuery("select * from student");
model->setHeaderData(0, Qt::Horizontal, tr("id"));
model->setHeaderData(1, Qt::Horizontal, tr("name song"));
QTableView *view = new QTableView;
view->setWindowTitle("ggg"); //修改窗口标题

view->setModel(model);
view->show();

MySqlQueryModel *myModel = new MySqlQueryModel; //创建自己模型的对象
myModel->setQuery("select * from student");
myModel->setHeaderData(0, Qt::Horizontal, tr("id"));
myModel->setHeaderData(1, Qt::Horizontal, tr("name"));
QTableView *view1 = new QTableView;
view1->setWindowTitle("mySqlQueryModel"); //修改窗口标题
view1->setModel(myModel);
view1->show();

int column = model->columnCount(); //获得列数
int row = model->rowCount();    // 获得行数
QSqlRecord record = model->record(1); //获得一条记录
QModelIndex index = model->index(1,1);   //获得一条记录的一个属性的值
qDebug() << "column num is:" << column << endl
<< "row num is:" << row << endl
<<"the second record is:" << record << endl
<< "the data of index(1,1) is:"<< index.data();

}

void MainWindow::on_pushButton_6_clicked()
{

}

void MainWindow::on_pushButton_7_clicked()
{
model->database().transaction(); //开始事务操作
if (model->submitAll()) {
model->database().commit(); //提交
} else {
model->database().rollback(); //回滚
QMessageBox::warning(this, tr("tableModel"),
tr("数据库错误: %1")
.arg(model->lastError().text()));
}
}

void MainWindow::on_pushButton_8_clicked()
{
model->revertAll();
}

void MainWindow::on_pushButton_9_clicked()
{
QString str=ui->lineEdit->text();

model->setFilter(tr("name='%1'").arg(str));
model->select();
}

void MainWindow::on_pushButton_10_clicked()
{   model->setTable("student");
model->select();
}

void MainWindow::on_pushButton_11_clicked()
{
model->setSort(0,Qt::AscendingOrder); //id属性，即第0列，升序排列
model->select();
}

void MainWindow::on_pushButton_12_clicked()
{
model->setSort(0,Qt::DescendingOrder); //id属性，即第0列，升序排列
model->select();
}

void MainWindow::on_pushButton_14_clicked()
{
int curRow = ui->tableView->currentIndex().row();
//获取选中的行
model->removeRow(curRow);
//删除该行
int ok = QMessageBox::warning(this,tr("删除当前行!"),tr("你确定"
"删除当前行吗？"),
QMessageBox::Yes,QMessageBox::No);
if(ok == QMessageBox::No)
{
model->revertAll(); //如果不删除，则撤销
}
else model->submitAll(); //否则提交，在数据库中删除该行
}

void MainWindow::on_pushButton_13_clicked()
{
int rowNum = model->rowCount(); //获得表的行数
//int id = 10;
model->insertRow(rowNum); //添加一行
model->setData(model->index(rowNum,0),rowNum+1);
model->setData(model->index(rowNum,1),"rowNum");
//model->submitAll(); //可以直接提交
}

最后的

model->setData(model->index(rowNum,0),rowNum+1);

此函数是给某条记录的某个字段赋值

参数1 model->index(rowNum,0)指定视图表格中的第rowNum行，从1开始，不是数据库的表第rowNum行，的字段0。

参数2 是实际要赋的值，上面的那个字段值指定为rowNum+1

比如，点击2次添加记录按钮



另外在add记录时，注意构造函数中手动提交和字段变化时自动提交的区别

model->setEditStrategy(QSqlTableModel::OnManualSubmit);

model->setEditStrategy(QSqlTableModel::OnFieldChange);