SQL Query very slow

[MvGulik]

Minor fixup's

...
def db_connect(self):

    #print(f'\nConnecting to: {self.db}') ## Py >= 3.6
    print('\nConnecting to: {}'.format(self.db))

    #self.dbcon = sqlite3.connect(self.db) ## TypeError: argument 1 must be str, not PosixPath
    self.dbcon = sqlite3.connect(str(self.db))
...