qt4 数据库操作---------tableView

 //connection.h
 #ifndef CONNECTION_H
 #define CONNECTION_H
 #include
 #include
 #include

 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
 #include "mainwindow.h"
 #include"connection.h"
 #include

 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
 #include
 #include
 #include
 #include
 #include
 #include "mysqlquerymodel.h"
 #include
 #include
 #include
 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);