从QSqlTableModel :: record返回的QSqlRecord为空

问题描述

|| 从QSqlTableModel和QTableView继承了一个FilmModel类。 我设定了模特

model = new FilmModel(this);
ui->filmList->setModel(model);

然后在QTableView插槽doubleClicked（QModelIndex index）中，我尝试获取记录。

QSqlRecord rr = model->record(index.row());
qDebug() << rr;

而且我得到空值。它会正确写入日志列名称，但是每个值都是\“ \”。我究竟做错了什么？在这里编写CREATE TABLE请求可能会很有用：

query.exec(\"CREATE TABLE IF NOT EXISTS films (\"
           \"id INTEGER  NOT NULL PRIMARY KEY AUTOINCREMENT,\"
           \"name VARCHAR,\"
           \"year SMALLINT UNSIGNED,\"
           \"country VARCHAR,\"
           \"director VARCHAR,\"
           \"actor VARCHAR,\"
           \"type TINYINT UNSIGNED,\"
           \"genre INT UNSIGNED,\"
           \"score TINYINT UNSIGNED,\"
           \"poster LONGBLOB)\");

RDBMS是SQLite。     

解决方法

我修改了另一个答案。这是我的代码，它可以工作：

//pro file:

QT       += core gui sql

TARGET = test1
TEMPLATE = app


SOURCES += main.cpp\\
           widget.cpp \\
           database.cpp

HEADERS  += widget.h \\
            database.h 


FORMS    += widget.ui

//database.h:
#ifndef DATABASE_H
#define DATABASE_H

#include <QSqlDatabase>

class Database
{
public:
    Database();
    ~Database();
    QSqlDatabase db;
    bool connection();
    void createTables();
};

#endif // DATABASE_H

//database.cpp:
#include \"database.h\"
#include <QtGui>
#include <QSqlQuery>

Database::Database()
{
    db = QSqlDatabase::addDatabase(\"QSQLITE\");
    db.setDatabaseName(\":memory:\");
}

Database::~Database()
{
    db.close();
}

bool Database::connection()
{
    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::Ok);
        return false;
    }
    return true;
}

void Database::createTables()
{
    QSqlQuery q;
    q.exec(\"CREATE TABLE test(id integer primary key,name varchar(20))\");

    q.exec(\"INSERT INTO test(name) VALUES(\'foo\')\");
    q.exec(\"INSERT INTO test(name) VALUES(\'fie\')\");
    q.exec(\"INSERT INTO test(name) VALUES(\'bar\')\");
}

//widget.h:
#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QModelIndex>
class QSqlQueryModel;
class Database;

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
private slots:
    void slotTest(QModelIndex idx);
private:
    QSqlQueryModel *model;
    Database *m_db;
    Ui::Widget *ui;
};

#endif

//widget.cpp:
#include \"widget.h\"
#include \"ui_widget.h\"
#include \"database.h\"
#include <QSqlQueryModel>
#include <QSqlRecord>
#include <QDebug>

Widget::Widget(QWidget *parent) :
    QWidget(parent),ui(new Ui::Widget)
{
    ui->setupUi(this);
    m_db = new Database();
    m_db->connection();
    m_db->createTables();
    model = new QSqlQueryModel();
    model->setQuery(\"SELECT * from test\");
    ui->tableView->setModel(model);
    connect(ui->tableView,SIGNAL(doubleClicked(QModelIndex)),this,SLOT(slotTest(QModelIndex)));
}

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

void Widget::slotTest(QModelIndex idx)
{
    QSqlRecord r;
    if(idx.isValid())
    {
        r = model->record(idx.row());
        qDebug() << r;
    }
}

//widget.ui:
<?xml version=\"1.0\" encoding=\"UTF-8\"?>
<ui version=\"4.0\">
 <class>Widget</class>
 <widget class=\"QWidget\" name=\"Widget\">
  <property name=\"geometry\">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>274</width>
    <height>210</height>
   </rect>
  </property>
  <property name=\"windowTitle\">
   <string>Widget</string>
  </property>
  <layout class=\"QVBoxLayout\" name=\"verticalLayout\">
   <item>
    <widget class=\"QTableView\" name=\"tableView\"/>
   </item>
  </layout>
 </widget>
 <layoutdefault spacing=\"6\" margin=\"11\"/>
 <resources/>
 <connections/>
</ui>

//main.cpp:
#include <QtGui/QApplication>
#include \"widget.h\"

int main(int argc,char *argv[])
{
    QApplication a(argc,argv);
    Widget w;
    w.show();
    return a.exec();
}