QT sqlite3数据库读取、容器操作、文件读写——学习笔记。

直接上代码

#include "dbpoi.h"#include <QtGui/QApplication>#include <QtCore/QCoreApplication>#include <QSqlDatabase>#include <QSqlQuery>#include <QSqlError>#include <QSqlDriver>#include <qDebug>#include <QString>#include <QVector>#include <QList>#include <QFile>#include <QSet>int main(int argc, char *argv[]){QApplication a(argc, argv);//dbPOI w; //QCoreApplication a(argc, argv);  //  QTextCodec::setCodecForCStrings(QTextCodec::codecForName("utf8"));QVector<int> tempFromNode;QVector<int> tempToNode;QSet <int> tempSort;    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");     db.setDatabaseName("NEW_AR_POI.sqlite"); // 数据库名与路径, 此时是放在同目录下// db.setDatabaseName("offset.db"); // 数据库名与路径, 此时是放在同目录下    bool ok = db.open(); // 连接数据库, 然后就可以使用了.if(ok){QSqlQuery query;  if (query.exec("select * from LinkNode_Table_bark "))   //尝试列出  表的所有记录{  //本次查询成功int numRows = 0;  //询问数据库驱动，是否驱动含有某种特性  if (db.driver()->hasFeature(QSqlDriver::QuerySize)){numRows = query.size();  //如果支持结果影响的行数，那么直接记录下来}else{query.last(); //否则定位到结果最后，qt 文档说，这个方法非常慢numRows = query.at() + 1;query.seek(-1);}}//尝试列出  表的所有记录while (query.next()) {int num =0;/*QString FNode_ID = query.value(4).toString();QString TNode_ID = query.value(5).toString();*/int FNode_ID = query.value(3).toInt();int TNode_ID = query.value(4).toInt();tempFromNode.append(FNode_ID);tempToNode.append(TNode_ID);}}else{  //qDebug() << "cannot open database.";printf( "cannot open database.");}QFile file( "file.txt" );if ( file.open(QIODevice::WriteOnly | QIODevice::Text)) {QTextStream stream( &file ); for ( int index =0; index < tempFromNode.size(); index ++ ){stream << tempFromNode.at(index);tempSort.insert(tempFromNode.at(index));tempSort.insert(tempToNode.at(index));stream<<"\t"<< tempToNode.at(index) <<endl ;}file.close();}//qSort(tempSort.begin(),tempSort.end());//tempSort.unite(tempSort);QFile filetTempSort( "tempSort.txt" );if ( filetTempSort.open(QIODevice::WriteOnly | QIODevice::Text)) {QTextStream stream( &filetTempSort );  foreach (const int &value, tempSort) { stream << value<<endl;  filetTempSort.close();}}QFile fileTp( "TP.txt" );if ( fileTp.open(QIODevice::WriteOnly | QIODevice::Text)) {QTextStream stream( &fileTp);  foreach (const int &value, tempSort) { stream << value; for ( int index =0; index < tempFromNode.size(); index ++ ){ if (tempFromNode.at(index) == value)   stream << "\t"<<tempToNode.at(index); }for ( int index =0; index < tempFromNode.size(); index ++ ){if (tempToNode.at(index) == value) stream << "\t"<<tempFromNode.at(index); } stream << endl;} fileTp.close();}//w.show();//return a.exec();return 0;}