注意：QT自带SQLITE数据库,不需要再安装
1.创建一个包含创建、查询、修改和删除数据库的数据库类(DataBase)
DataBase.h头文件
#pragma once #include <QObject>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlQuery>
#include <QtSql/QSqlDriver>
#include <QtSql/QSqlError>
#include "client_global.h" struct StudentData
{
QString name;
int score;
QString grade;
}; class DataBase : public QObject
{
Q_OBJECT public:
DataBase(QString name,QObject *parent=);
~DataBase();
public:
bool insertData(StudentData data);
bool deleteData(int name);
bool getDataByName(int name, StudentData & data);
bool getDataList(QList<StudentData> & list);
bool update();
private:
QSqlDatabase m_DataBase;
private:
bool initTable();
bool isExistTable(QString table);
bool createTable(QString table);
};
DataBase.cpp源文件
#include "XDataBase.h"
#include <QCoreApplication>
#include <QDebug>
#include <QSqlRecord> DataBase::DataBase(QString name, QObject *parent)
: QObject(parent)
{ if (QSqlDatabase::contains(name)) { m_DataBase = QSqlDatabase::database(name);
}
else { m_DataBase = QSqlDatabase::addDatabase("QSQLITE");
m_DataBase.setDatabaseName(name+".db");
m_DataBase.setDatabaseName(QCoreApplication::applicationDirPath()+"//"+ name);
}
initTable();
} DataBase::~DataBase()
{
} bool DataBase::initTable()
{
if (!m_DataBase.open()) {
return false;
} if (!isExistTable("students")) {
createTable("students");
}
return false;
} bool DataBase::isExistTable(QString table)
{
bool bRet = false;
if (!m_DataBase.open()) {
return bRet;
}
QSqlQuery query(m_DataBase);
query.exec(QString("select count(*) from sqlite_master where type='table' and name='%1'").arg(table)); //关键的判断
if (query.next())
{
if (query.value().toInt() > )
{
bRet = true;
}
}
return false;
} bool DataBase::createTable(QString table)
{
if (!m_DataBase.open()) {
return false;
} QSqlQuery query(m_DataBase);
if (table == QString("students")) { bool success = query.exec("CREATE TABLE students ("
"id INTEGER PRIMARY KEY AUTOINCREMENT, "
"name VARCHAR(40) NOT NULL, "
"score INTEGER NOT NULL, "
"grade VARCHAR(40) NOT NULL)"); if (success) {
return true; //新建数据库成功
}
else {
QSqlError lastError = query.lastError();
QString err = lastError.driverText();
return false;
}
}
else {
return false;
}
} bool DataBase::insertData(StudentData data)
{
if (!m_DataBase.open()) {
return false;
}
QSqlQuery query(m_DataBase); bool success = query.exec(QString("INSERT INTO students (name, score,class) "
"VALUES (%1, %2, %3)").arg(data.name)
.arg(data.score)
.arg(data.grade)); if (!success) { QSqlError lastError = query.lastError();
QString err = lastError.driverText();
return false;
}
return true;
} bool DataBase::deleteData(QString name)
{
if (!m_DataBase.open()) {
return false;
}
QSqlQuery query(m_DataBase);
query.prepare(QString("DELETE FROM students WHERE name='%1'").arg(name));
query.exec();
return false;
} bool DataBase::getDataByName(int name, StudentData & data)
{
if (!m_DataBase.open()) {
return false;
}
QSqlQuery query(m_DataBase);
query.prepare(QString("SELECT * FROM students WHERE name='%1'").arg(name));
query.exec();
QSqlRecord rec = query.record();
if (query.next())
{ data.name = query.value().toString();
data.score = query.value().toInt();
data.grade = query.value().toString(); return true;
}
return false;
} bool DataBase::getDataList(QList<StudentData>& list)
{
if (!m_DataBase.open()) {
return false;
} QSqlQuery query(m_DataBase);
query.prepare(QString("SELECT * FROM students"));
query.exec();
QSqlRecord rec = query.record();
while (query.next())
{
StudentData data;
device.name = query.value().toInt();
device.score = query.value().toString();
device.grade = query.value().toInt();
list.append(data);
return true;
}
return false;
} bool DataBase::update()
{
if (!m_DataBase.open()) {
return false;
} QSqlQuery query(m_DataBase);
query.prepare("UPDATE students SET score = 100 , name = '小A'");
query.exec();
return false;
}
调用：
XClientApp.h头文件
#pragma once #include <QApplication>
#include <DataBase.h>
#include "ServerAPI.h"
#define clientApp static_cast<XClientApp*>(QCoreApplication::instance()) class XClientApp : public QApplication
{
Q_OBJECT public:
XClientApp(int argc, char *argv[]);
~XClientApp();
DataBase* getDataBase();
ServerAPI* getServerAPI();
QString getAppName();
private:
void setFont(QString font);
void setStyle();
private:
DataBase* m_pDataBase;
ServerAPI* m_pServerAPI;
signals:
void sglSystemMessage(QString type, QString data);
};
XClientApp.cpp源文件
#include "XClientApp.h" XClientApp::XClientApp(int argc, char *argv[])
: QApplication(argc, argv)
{ m_pDataBase = new DataBase("xclient", this);
setWindowIcon(QIcon(":/Images/Resources/朱砂古镇.ico"));//可执行程序图标
setStyle();
m_pServerAPI = new ServerAPI(this); //注意有重载
} DataBase * XClientApp::getDataBase() //获取本地数据库并进行操作
{
return m_pDataBase;
}