QT SQlite Abstraction Class

sqlite_class.cpp

#include "sqlite_class.h"


Sqlite_Class::Sqlite_Class(QString filename)
{
    
    db = QSqlDatabase::addDatabase("QSQLITE");

    QString db_path = QDir::currentPath();
    qDebug() << db_path;    //current path

    db_path = db_path + filename;
    db.setDatabaseName(db_path);
    db.open();
    qDebug() << "Sqlite Connection: " <<db.lastError();
    
    QSqlQuery qry;
    query = qry;

}

int Sqlite_Class::sql_select(QString select, QString from, QString where){
    QString sql = QString("SELECT ") + select + QString(" FROM ") + from + QString(" WHERE ") + where ;
    qDebug() << sql;
   
    query.exec(sql);

    return 0;
}

int Sqlite_Class::sql_insert(QString table, QStringList data, QStringList values){

    QString sql = QString("INSERT INTO ") + table + QString(" ( ")  ;
    QString   dt = "";
    QString vl = "";
    for(int i = 0; i < data.size(); i++){
       
        dt = dt + QString("`") + data.at(i) + QString("`") + QString(",");
        vl = vl + QString("'") + values.at(i) + QString("'") + QString(",");
    }

    dt.chop(1);
    vl.chop(1);


    sql = sql + dt + QString(") ") + QString("VALUES(") + vl + QString(")");

    query.exec(sql);
    qDebug() << db.lastError();
    return query.numRowsAffected();
}

int Sqlite_Class::sql_update(QString table, QStringList data, QStringList values, QString where){

    QString sql = QString("UPDATE `") + table + QString("` SET ")  ;
    QString   dt = "";
    QString vl = "";
    QString temp = "";
    for(int i = 0; i < data.size(); i++){

        temp = temp + QString("`") + data.at(i) + QString("`") + QString("=") + QString("'") + values.at(i) + QString("'") + QString(",");
    }

    temp.chop(1);
    sql = sql + temp + QString(" WHERE ") + where;
    qDebug() << sql;


    query.exec(sql);
    qDebug() << db.lastError();
    return query.numRowsAffected();
}



QSqlError Sqlite_Class::sql_getLastError(){
    return db.lastError();
}

int Sqlite_Class::sql_delete(QString table, QString where){
    QString sql = QString("DELETE ") + QString("FROM ") + table + QString(" WHERE ") + where ;
    qDebug() << sql;
    QSqlQuery qry;
    qry.exec(sql);
    query = qry;
    return 0;

}

QSqlQuery Sqlite_Class::sql_getResults(){
    return query;
}

sqlite_class.h

#ifndef SQLITE_CLASS_H
#define SQLITE_CLASS_H

#include <QApplication>
#include <QSqlDatabase>
#include <QSql>
#include <QSqlError>
#include <QDir>
#include <QFile>
#include <QDebug>
#include <QSqlQuery>
#include <QString>
#include <QStringList>
#include <QSqlError>

class Sqlite_Class
{
public:
    Sqlite_Class(QString str);
    int sql_insert(QString table, QStringList data, QStringList values);
    int sql_select(QString select, QString from, QString where);
    int sql_update(QString table, QStringList data, QStringList values, QString where);
    int sql_delete(QString table, QString where);
    QSqlQuery sql_getResults();
    QSqlError sql_getLastError();
 private:
    QSqlQuery query;
    QSqlDatabase db;
};

#endif // SQLITE_CLASS_H

Don't forget to add:
QT += sql

in your .pro file.