qt - pyqt QTableView not populating when changing databases.

Question

I'm trying to allow my users to pick which database to open. Each database will have the same schema. For some reason though I can't get my QTableView to populate after I open the database.

I'm paraphrasing the example code but this should give you an idea of what I'm trying to do.

works:

class aMainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self):
        QMainWindow.__init__(self)

        self.db = QSqlDatabase.addDatabase("QSQLITE")

        self.db.setDatabaseName('testdb.db')
        self.db.open()   

        # Set up the user interface from Designer.
        self.setupUi(self)

        #self.db.setDatabaseName('testdb.db')

        self.model = QSqlTableModel(self)
        self.model.setTable("records")

        self.model.setSort(FILEORDER, Qt.AscendingOrder)

        self.model.setHeaderData(ID, Qt.Horizontal, QVariant("ID"))
        self.model.setHeaderData(FILEORDER, Qt.Horizontal, QVariant("File Order"))
        self.model.setHeaderData(RECORDTYPE, Qt.Horizontal, QVariant("Type"))
        self.model.setHeaderData(NAME, Qt.Horizontal, QVariant("Name"))
        self.model.setHeaderData(PRESORTNAME, Qt.Horizontal, QVariant("Presort Name"))
        self.model.setHeaderData(RECORD, Qt.Horizontal, QVariant("Record"))
        self.model.select()

        self.tableView.setModel(self.model)
        #self.view.setSelectionMode(QTableView.SingleSelection)
        #self.view.setSelectionBehavior(QTableView.SelectRows)
        self.tableView.setColumnHidden(ID, True)
        self.tableView.setColumnHidden(PRESORTNAME, True)
        self.tableView.setColumnHidden(RECORD, True)

doesn't work:

class aMainWindow(QMainWindow, Ui_MainWindow):       
    def __init__(self):
        QMainWindow.__init__(self)

        # Set up the user interface from Designer.
        self.setupUi(self)

        #self.db.setDatabaseName('testdb.db')

        self.model = QSqlTableModel(self)
        self.model.setTable("records")

        self.model.setSort(FILEORDER, Qt.AscendingOrder)

        self.model.setHeaderData(ID, Qt.Horizontal, QVariant("ID"))
        self.model.setHeaderData(FILEORDER, Qt.Horizontal, QVariant("File Order"))
        self.model.setHeaderData(RECORDTYPE, Qt.Horizontal, QVariant("Type"))
        self.model.setHeaderData(NAME, Qt.Horizontal, QVariant("Name"))
        self.model.setHeaderData(PRESORTNAME, Qt.Horizontal, QVariant("Presort Name"))
        self.model.setHeaderData(RECORD, Qt.Horizontal, QVariant("Record"))
        self.model.select()

        self.tableView.setModel(self.model)
        #self.view.setSelectionMode(QTableView.SingleSelection)
        #self.view.setSelectionBehavior(QTableView.SelectRows)
        self.tableView.setColumnHidden(ID, True)
        self.tableView.setColumnHidden(PRESORTNAME, True)
        self.tableView.setColumnHidden(RECORD, True) 


    #slot of the open db action
    def on_actionOpen_DB_triggered(self, checked=None):
        if checked is None: return
        filename = QFileDialog.getOpenFileName(self, 'open a database', 
                        '/home/',
                        "Databases (*.db)", #All Files (*.*)
                        "Databases (*.db)")
        if not filename:
            pass

        self.db = QSqlDatabase.addDatabase("QSQLITE")


        if self.db.isOpen():
            sys.stdout.write('db still open?')            

        self.db.setDatabaseName(filename)
        self.dbname = filename
        self.db.open()
        self.model.select()
        #self.tableView.update()
        if self.db.isOpen():
            sys.stdout.write('db opened')

Answer 1

I can't remember today exactly where I found it but as I was researching something else I found some forum posting that said the connection must be made before making the model. I suspect there must be some code in the model construct that's touching the db. I changed my on_actionOpen_DB_triggered to create the model after making the connection and it works just fine.