Create database

[snaderi]

hello,I create an app that use for save data,but i have an problom!I want when my app execute on other computer for the frist time,automatically create databse on that comuter if not exist! please help me!!

[SergioDanielG]

Hi snaderi.
Which database are you using?
Maybe you can verify if database file exists ( or connection it's possible) at startup and if not, call a function to create database.
Regards.

[snaderi]

I use MySQL,when I execute my app other computer thats return this Error:
UnKnown database 'mydb' QMYSQL:Unable to connect.

please help me.

[SergioDanielG]

Did you verify if other computer can accest to mysql server?
How do you are connecting to mysql server? Can you put a little part of your code here?
Regards

[snaderi]

thank you
my connecting file cantains this code:
@bool createConnection()
{
QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("localhost");
db.setDatabaseName("sa2");
db.setUserName("root");
db.setPassword("");

if (!db.open()) {
    QMessageBox::critical(0,QObject::tr("Database Error"),
                          db.lastError().text());
    return false;
}

    return true;

}@

I have only one problem and thats is I forced to create db manually.I want my db create automatically!

[SergioDanielG]

Well, you must to use sql commands to do this, and some modifications on your code.
Try this
@ QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("localhost");
db.setUserName("root");
db.setPassword("sdg2101zmv");

if (!db.isValid()){
    qDebug() << db.lastError().text();
    return;
}

db.open();
QString query = "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = 'sa2'";
QSqlQuery q = db.exec&#40;query&#41;;

if (q.size() == 0){
    db.exec&#40;"CREATE DATABASE IF NOT EXISTS sa2;"&#41;;
    qDebug() << db.lastError().text();
    db.setDatabaseName("sa2");
    bool yourApp::createTables();
}

@

Where
@
bool yourApp::createTables();
@

is necesary if you need create tables to your new database.
First quere count all databases named "sa2".
Regars.

[snaderi]

thanks very much!but this Error occured on line 8:
return-statement with no value, in function returning 'bool' [-fpermissive]

[SergioDanielG]

Sure. You must to ajust my example to your code.
In this case replace line 8 to
@return false;
@

Or don't return and put some message to app user.
Regards.

[snaderi]

thanks very much!its work very well!!!