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!!!