Selecting data from mysql using qt?

lyuts

Wow, mysql is full of surprises. Never got those with psql. ¤ Dii ¤, does it have \q command?

doforumda

yes i get into mysql command line

doforumda

whats the reason that my database is not opening in qt?

Dii

lyuts: yes \q is working too

doforumda: ok, so get into the mysql comand line with the command above

/opt/lampp/bin/mysql -D testTwo -h localhost -u root -p

and then do this:

grant all on testTwo.* to 'root'@'localhost' ;

Then we have a working mysql, and the rights are granted, we can get back to your Qt program.

lyuts

I hope the next post will be like "Hooray, I got it working!!!" :)

doforumda

there is an error in sql syntax
@
mysql> grant all on testTwo.* to ‘root’@’localhost’;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '��root’@’localhost’' at line 1
@

Dii

Ok, back to your Qt program:

@#include <QApplication>
#include <QtSql>

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setDatabaseName("testTwo");
db.setUserName("root");
db.setPassword("");
db.setHostName("localhost");

bool ok = db.open();
qDebug() << ok;

QSqlQuery query;
query.exec&#40;"SELECT firstname,lastname FROM testTable"&#41;;
while(query.next()) {
    QString firstName = query.value(0).toString();
    QString secondName = query.value(1).toString();
    qDebug() << "First Name: " << firstName << "Last Name:" << secondName;
    qDebug() << db.lastError();
}
return 0;

}@

Notice, we don't set a password here.
The end is 'return 0' instead of 'a.exec()', and it won't hang. The exec() starts the main event loop, and you don't use it here...

lyuts

I think you need to check apostrophes in that command.

Dii

ok, you have wrong apostrof type there. I mean this >> '

doforumda

i tried without apostrophes as well but same error

Dii

nope, you had ` before the root and not '
that was the error

Dii

ok, wait a second, I checked it in the meantime and it won't work without password, stay tuned, I post the right command

doforumda

you mean like this
grant all on testTwo.* to root@localhost ;
if yes it also displaying same error

Dii

so, here we go:

grant all on testTwo.* to 'root'@'localhost' identified by 'password';

Make the right apostrophes! :) You have to set the password in your Qt app too.

Dii

ok, wait I see

Dii

the Devnet's forum motor changes the apostrophes somehow... use the straight apostrophes everywhere
I mean this @'@

doforumda

mysql query did its job its now successful but when i use qt code and try to make it run it displays same error

@
Starting /home/zafar/c++/dbExample-build-desktop/dbExample...
false
QSqlQuery::exec: database not open
/home/zafar/c++/dbExample-build-desktop/dbExample exited with code 0
@

doforumda

wait i think the query is not sucessful because it displays this message 0 rows affected
@
mysql> grant all on testTwo.* to 'root'at'localhost' identified by 'password';
Query OK, 0 rows affected (0.01 sec)
@

lyuts

Add this to your code after connecting:

@qDebug() << db.lastError().text();@

And tell us what the error is.

lyuts

[quote author="doforumda" date="1286877766"]wait i think the query is not sucessful because it displays this message 0 rows affected
@
mysql> grant all on testTwo.* to 'root'at'localhost' identified by 'password';
Query OK, 0 rows affected (0.01 sec)
@[/quote]

Did you run that command with 'password' instead of '123456'?