QT MYSQL Database connectivity problems?

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I have used the following code to connect to the mysql database, the connection succeeds, but nothing is happened in the database and also no table is created and the rows are not indeed updated. Kindly help me on this issue..

QSqlDatabase db= QSqlDatabase::addDatabase("QODBC");
     db.setDatabaseName("DRIVER={MYSQL ODBC 3.51 Driver};FIL={MYSQL};DBQ=screengrabber");
     db.setHostName("localhost");
     //db.setConnectOptions("CLIENT_ODBC");
     //db.setDatabaseName("screengrabber");
     db.setUserName("root");
     db.setPassword("1");
     ok = db.open();////Here ok is true...

     QSqlQuery query;
       query.exec("create table person (id int primary key, "
                  "firstname varchar(20), lastname varchar(20))");
       query.exec("insert into person values(101, 'Danny', 'Young')");

Default Re: MYSQL Qt connectivity?? I have used the following query which succees in inserting into the table. But how to bind the values instead of directly giving the values as below::
Qt Code:

bool qrylog=querylog.exec("INSERT INTO service_log (ip_address,date_time, service_status, logged_user) " "VALUES ('172.16.0.51','2011-07-28 15:55:09',1,'ramachandran')");

Here in database ip_address is varchar(20), date_time is datetime, service_status is integer and logged_user is varchar(30). Please help me fixing this issue::

Posted 27-Jul-11 19:08pm

Gokulnath007

Updated 28-Jul-11 0:51am

v2

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Kim Togo · Answer 1 · 2011-07-27T21:01:00

Solution 1

You have to tell QSqlQuery how to "talk" to the databasse.

http://doc.qt.nokia.com/latest/qsqlquery.html#QSqlQuery-3[^]

C

QSqlQuery query = db.exec("create table person (id int primary key, firstname varchar(20), lastname varchar(20))");
query.exec("insert into person values(101, 'Danny', 'Young')");

or

C

QSqlQuery query(db);
query.exec("create table person (id int primary key, firstname varchar(20), lastname varchar(20))");
query.exec("insert into person values(101, 'Danny', 'Young')");

For binding values[^] aka SqlParameter.

Posted 27-Jul-11 21:01pm

Kim Togo

Updated 28-Jul-11 0:55am

v3

Comments

Gokulnath007 28-Jul-11 3:33am

Could you please explain with the code what i have used, any modifications to be done with it.. Thank You!!!

Kim Togo 28-Jul-11 3:39am

You can do a:

QSqlQuery query = db.exec("create table person (id int primary key, firstname varchar(20), lastname varchar(20))");
query.exec("insert into person values(101, 'Danny', 'Young')");

or

QSqlQuery query(db);

query.exec("create table person (id int primary key, firstname varchar(20), lastname varchar(20))");
query.exec("insert into person values(101, 'Danny', 'Young')");

Gokulnath007 28-Jul-11 6:50am

Default Re: MYSQL Qt connectivity??

I have used the following query which succees in inserting into the table. But how to bind the values instead of directly giving the values as below::
Qt Code:

bool qrylog=querylog.exec("INSERT INTO service_log (ip_address,date_time, service_status, logged_user) "
"VALUES ('172.16.0.51','2011-07-28 15:55:09',1,'ramachandran')");

Here in database ip_address is varchar(20), date_time is datetime, service_status is integer and
logged_user is varchar(30).

Please help me fixing this issue::

Kim Togo 28-Jul-11 6:52am

See approaches-to-binding-values

There is some good examples on how to :-)

Gokulnath007 28-Jul-11 7:07am

I have used the following code where nothing is added in two rows, 0 and continuous 0 has been added along the ip_address and datetime column respectively.

QString ipname="gok";
QString datetime="2011-07-28 15:55:09";
int serv=1;

QSqlQuery querylog(db);
querylog.prepare("INSERT INTO service_log (ip_address,date_time, service_status, logged_user) "
"VALUES (ip_address, date_time, service_status, logged_user)");
querylog.bindValue("ip_address",ipname);
querylog.bindValue("date_time",datetime);
querylog.bindValue("service_status",serv);
querylog.bindValue("logged_user",hostname);

Kim Togo 28-Jul-11 7:10am

Change "VALUES (ip_address, date_time, service_status, logged_user)" to:

"VALUES (:ip_address, :date_time, :service_status, :logged_user)" and

querylog.bindValue(":ip_address",ipname);
querylog.bindValue(":date_time",datetime);
querylog.bindValue(":service_status",serv);
querylog.bindValue(":logged_user",hostname);

Look, I have added a : tag as described in the link to approaches-to-binding-values.

Gokulnath007 28-Jul-11 7:13am

I have tried with that also, but it fails.

Kim Togo 28-Jul-11 7:18am

Strange.. Have you tried the other versions of binding-values? - Hmm. I think it has something to do with ODBC driver ( and the ODBC driver v 3.51 for MySql is really old one, you can download a version 5.1.8 now ).

Try "version 2".

"VALUES (?, ?, ?, ?)" and

querylog.bindValue(ipname);
querylog.bindValue(datetime);
querylog.bindValue(serv);
querylog.bindValue(hostname);

Gokulnath007 28-Jul-11 7:20am

Do we need to convert all values into QVariant before calling bindValue() function.

Kim Togo 28-Jul-11 7:25am

For "version 2" example change
querylog.bindValue(ipname);

to

querylog.addBindValue(ipname);

Gokulnath007 28-Jul-11 7:22am

How to get that version and install in order to invoke in our coding??

Kim Togo 28-Jul-11 7:26am

The newest version MySql ODBC can be downloaded her:

http://dev.mysql.com/downloads/connector/odbc/

Gokulnath007 28-Jul-11 7:29am

I have already installed odbc 5.1 only...

Kim Togo 28-Jul-11 7:30am

Good. But in the connection you have specified "MYSQL ODBC 3.51 Driver".
Check out http://www.connectionstrings.com/mysql#p31

Gokulnath007 28-Jul-11 7:29am

I am using this code::

QSqlDatabase db= QSqlDatabase::addDatabase("QMYSQL3");
DBQ=screengrabber");
db.setHostName("localhost");
//db.setConnectOptions("CLIENT_ODBC");
db.setDatabaseName("screengrabber");
db.setUserName("root");
db.setPassword("1");
ok = db.open();

Gokulnath007 28-Jul-11 7:32am

I modified the code and now am using this code only...

QT MYSQL Database connectivity problems?

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