unable to insert into mysql table

[mohanakrishnan]

hi
im unable to insert a record into the table but im able to execute the select
query..i checked ,the db connection is true..

QSqlDatabase db1=QSqlDatabase::database("ganesh");
if(db1.open())
{
  qDebug()<<"connection ok";
QSqlQuery query;
        query.exec("insert into waitrequest(bednumber)values('123')");
}

QSqlDatabase db1=QSqlDatabase::database("ganesh");
if(db1.open())
{
  qDebug()<<"connection ok";
QSqlQuery query;
        query.exec("insert into waitrequest(bednumber)values('123')");
}

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but it shows message like below...
QSqlQuery:: exec: database not open
but if i use select query i get the result!!.
any help is highly respected!!
thanks...