思路：　　1.初始化的时候首先调用次线程初始化数据库2.初始化QSqlTabelModel等3.使用到数据库的地方要验证数据库句柄,如果已失效,要再次调用次线程.

1.connect不识别QSqlDatabase类型,要使用qRegisterMetaType注册.
2.如果使用了QSqlTableModel,要在数据库连接成功后初始化.

#ifndef THREAD_H
#define THREAD_H#include <QThread>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlError>
#include "config.h"class Thread : public QThread
{Q_OBJECTpublic:Thread();~Thread();void stop();QSqlDatabase dbhandle;bool correct;QString returncode;
signals:void execresult(QSqlDatabase db,bool correct = true,QString returncode = "");
protected:void run();
};#endif // THREAD_H

#include "thread.h"Thread::Thread()
{this->correct       = false;this->returncode    = "";
}void Thread::run()
{dbhandle    = QSqlDatabase::addDatabase("QMYSQL");dbhandle.setHostName(DB_ADDR);dbhandle.setUserName(DB_USER);dbhandle.setPassword(DB_PASS);dbhandle.setPort(DB_PORT);dbhandle.setDatabaseName(DB_DB);if(dbhandle.open())this->correct       = true;else{this->correct       = false;this->returncode    = dbhandle.lastError().text();}this->stop();
}void Thread::stop()
{emit execresult(dbhandle,correct,returncode);
}Thread::~Thread()
{}

void Cafes_Income::init_db_return(QSqlDatabase db, bool correct, QString errorstr)
{initdbdialog->close();if(!correct){QMessageBox::information(this,tr("数据库初始化失败！"),errorstr);exit(EXIT_FAILURE);}this->dbhandle  = db;
}

if(!dbhandle.isValid())this->init_database_link();

/** 名称:init_database_link* 作用:初始化数据库链接* 参数:no* 返回:void*/
void Cafes_Income::init_database_link()
{if(!dbhandle.isOpen()){this->initdb->start();initdbdialog->exec();}
}