How to use SQLite in QT5

SQLite (sql) is an open source and lightweight database software that does not require a server and can be integrated into other software, making it very suitable for embedded systems.
Versions above Qt5 can use SQLite directly.

1. Modify the .pro file and add the SQL module:

QT += sql

2. The main.cpp code is as follows:

#include "mainwindow.h"
#include <QApplication>
//添加头文件
#include <qdebug.h>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    //建立并打开数据库
    QSqlDatabase database;
    database = QSqlDatabase::addDatabase("QSQLITE");
    database.setDatabaseName("MyDataBase.db");
    if (!database.open())
    {
        qDebug() << "Error: Failed to connect database." << database.lastError();
    }
    else
    {
        qDebug() << "Succeed to connect database." ;
    }

    //创建表格
    QSqlQuery sql_query;
    if(!sql_query.exec("create table student(id int primary key, name text, age int)"))
    {
        qDebug() << "Error: Fail to create table."<< sql_query.lastError();
    }
    else
    {
        qDebug() << "Table created!";
    }

    //插入数据
    if(!sql_query.exec("INSERT INTO student VALUES(1, \"Wang\", 23)"))
    {
        qDebug() << sql_query.lastError();
    }
    else
    {
        qDebug() << "inserted Wang!";
    }
    if(!sql_query.exec("INSERT INTO student VALUES(2, \"Li\", 23)"))
    {
        qDebug() << sql_query.lastError();
    }
    else
    {
        qDebug() << "inserted Li!";
    }

    //修改数据
    sql_query.exec("update student set name = \"QT\" where id = 1");
    if(!sql_query.exec())
    {
        qDebug() << sql_query.lastError();
    }
    else
    {
        qDebug() << "updated!";
    }

    //查询数据
    sql_query.exec("select * from student");
    if(!sql_query.exec())
    {
        qDebug()<<sql_query.lastError();
    }
    else
    {
        while(sql_query.next())
        {
            int id = sql_query.value(0).toInt();
            QString name = sql_query.value(1).toString();
            int age = sql_query.value(2).toInt();
            qDebug()<<QString("id:%1    name:%2    age:%3").arg(id).arg(name).arg(age);
        }
    }

    //删除数据
    sql_query.exec("delete from student where id = 1");
    if(!sql_query.exec())
    {
        qDebug()<<sql_query.lastError();
    }
    else
    {
        qDebug()<<"deleted!";
    }

    //删除表格
    sql_query.exec("drop table student");
    if(sql_query.exec())
    {
        qDebug() << sql_query.lastError();
    }
    else
    {
        qDebug() << "table cleared";
    }

    //关闭数据库
    database.close();
    return a.exec();
}

3. The application output is as follows:

 

4. The created MyDataBase.db is in this folder of build:
D:\QT\project\build-sl-Desktop_Qt_5_10_1_MinGW_32bit-Debug

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