getting already open database connection

[user4592357]

i have a table view which needs to display info from database. i'm using QSqlDatabase. this is how i open a db connection:

auto db = QSqlDatabase::database();
db.setDatabaseName(m_sDatabasePath);
if (!db.open())
	error(arg(db.lastError().text());

later i use queries like this one to retrieve the info:

QSqlQuery sqlQuery(QSqlDatabase::database());
if (sqlQuery.exec(...) && sqlQuery.first())
	...

since i'm using the default connection, when i open a new database i cannot use these queries to retrieve info from old connection. i know that i should name the connections and access them via name, but...
use scenario is the following:

1. open db #1, issue queries, display data in view (table tab)
2. open db #2, issue queries, display data in new table tab
3. switch back to old tab, problem: queries are still executed on db #2 (default connection).

so i changed connection opening to this:

auto db = QSqlDatabase::addDatabase("QSQLITE", sDatabasePath);
db.setDatabaseName(sDatabasePath);
if (!db.open())
	error(arg(db.lastError().text());

and changed the queries to this:

QSqlQuery sqlQuery(QSqlDatabase::database(m_info->getDatabasePath()));

now, when i execute a query, i get Parameter count mismatch error, and i'm not sure why, because before this change everything worked correctly (for default connection).

[Christian Ehrlicher]

Don't think this has something to do with the other database connection. I would take a look at the query where it fails, and check what QSqlQuery::error() and database() really returns.

[user4592357]

@Christian-Ehrlicher
the error is from QSqlQuery::lastError().
and it worked with default connection

[Christian Ehrlicher]

Please show the query, make sure that the db is really open at the time you're trying to execute the query.

[SGaist]

Hi,

To add to @Christian-Ehrlicher, I am not sure that using a file path is necessarily a good idea for a connection name.

[user4592357]

@SGaist
then what should i be using?

[SGaist]

A meaningful identifier, just the name of the database, etc. That's up to you.

[user4592357]

@SGaist
yeah something unique, so i thought file path would be more unique then fine name

[SGaist]

In any case, you should do as @Christian-Ehrlicher wrote: get the error from the failed query.

[user4592357]

@SGaist
the parameter mismatch error is the text given by lastError()

[SGaist]

And what is the query ? The one returned by lastQuery ?

[user4592357]

actually prepare() was failing and i got the error from sql query at right after prepare() and it was meaningful