I am creating a simple qt application to provide details and login to the application and retrieve details from the database.It has mainly 2 forms(MainWindow and Dialog) A DBconncetion class has been written to obtain a database connection! I used the DBconnection class to log into application by giving details via the MainWindow form! but I don't know how to keep the connection that I opened in the MainWindow form and use it to retreive the data to the tableview in the Dialog form.
mycode is as follows
DBconnection.h (working successfully)
public:
QSqlDatabase mydb;
bool connOpen(QString uname,QString pword,QString ip,int port,QString dbname){
mydb=QSqlDatabase::addDatabase("QOCI","MyDB");
mydb.setUserName(uname);
mydb.setPassword(pword);
mydb.setHostName(ip);
mydb.setPort(port);
mydb.setDatabaseName(dbname);
mydb.open();
return true;
}
MainWindow.cpp (working successfully)
void MainWindow::on_pushButton_clicked()
{
DBconnection con;
if(con.connOpen(ui->lineEdit->text(),ui->lineEdit_2->text(),ui->lineEdit_3->text(),ui->lineEdit_4->text().toInt(),ui->lineEdit_5->text())){
Dialog dialog1;
dialog1.setModal(true);
dialog1.exec();
}
}
Dialog.cpp (not working)
void Dialog::on_pushButton_clicked()
{
QSqlQueryModel *modal = new QSqlQueryModel();
con.connOpen();
QSqlQuery* qry=new QSqlQuery(con.mydb);
qry->prepare("select NAME FROM TEST1");
qry->exec();
modal->setQuery(*qry);
ui->tableView->setModel(modal);
}
How can I adjust my code so that I can retrieve data to the tablewidget in Dialog form from the connection I made from the MainWindow form?
You could either pass a reference to the connection to your dialog, or make the connection static/global.
eg1
class Dialog()
{
DBconnection &con;
Dialog(DBconnection &con) : con(con) {};
};
Instead of a reference, you might also want to use a std::shared_ptr
.
A nice way of making the connection global/static would be through the Service locator pattern . This pattern uses a central registry known as the "service locator", which on request returns the information necessary to perform a certain task.
You might also want to have a look into things related to "Dependency injection"
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