Error connecting to MySQL from Python

[Carlos Ortiz]

On Saturday, October 12, 2013 12:13:05 PM UTC-5, MRAB wrote:
> On 12/10/2013 17:09, carlos.o... at gmail.com wrote:
> 
> > Hello guys I am currently working in a python project at my school. First I want to make clear that I'm not a python programmer (I was just called to put out the flames in this project because no one else would and I was brave enough to say yes).
> 
> >
> 
> > I have the following problem here. I have to write a method that connects to an existing localhost MySQL database (I'm using connector version 1.0.12) and then does pretty basic stuff. The parameters are sent by a GTK-written GUI (I didn't write that interface). So I wrote my method like this:
> 
> >
> 
> > --------------------------PYTHON  CODE----------------------------------------
> 
> >    def compMySQL(self, user, database, password, db_level, table_level, column_level):
> 
> >      sql_page_textview = self.mainTree.get_widget('sql_text_view')
> 
> >      sql_page_textview.modify_font(pango.FontDescription("courier 10"))
> 
> >      sql_page_buffer = sql_page_textview.get_buffer()
> 
> >
> 
> >      #Gonna try connecting to DB
> 
> >      try:
> 
> >        print("Calling conn with U:{0} P:{1} DB:{2}".format(user,password,database))
> 
> >        cnxOMC = mysql.connector.connect(user, password,'localhost',database)
> 
> >      except:
> 
> >        print "Error: Database connection failed. User name or Database name may be wrong"
> 
> >        return
> 
> >
> 
> >      #More code ...
> 
> > ------------------------END OF PYTHON CODE-------------------------------------
> 
> >
> 
> >
> 
> > But when I run my code I get this:
> 
> >
> 
> > -----------------------------CONSOLE OUTPUT------------------------------------
> 
> > Calling conn with U:root P:PK17LP12r DB:TESTERS
> 
> > Error: Database connection failed. User name or Database name may be wrong
> 
> > ---------------------------END OF COLSOLE OUTPUT-------------------------------
> 
> >
> 
> > And I don't know why, since the arguments sent are the same arguments that get printed (telling me that the GUI the other guy coded works fine) and they are valid login parameters. If I hardcode the login parameters directly insetad of using the GUI everything goes ok and the functions executes properly; the following code executes nice and smooth:
> 
> >
> 
> > --------------------------PYTHON  CODE-----------------------------------------
> 
> > def compMySQL(self, user, database, password, db_level, table_level, column_level):
> 
> >      sql_page_textview = self.mainTree.get_widget('sql_text_view')
> 
> >      sql_page_textview.modify_font(pango.FontDescription("courier 10"))
> 
> >      sql_page_buffer = sql_page_textview.get_buffer()
> 
> >
> 
> >      #Gonna try hardcoding
> 
> >      try:
> 
> >        #print("Calling conn with U:{0} P:{1} DB:{2}".format(user,password,database))
> 
> >        cnxOMC = mysql.connector.connect(user="root", password='PK17LP12r',host='localhost',database='TESTERS')
> 
> >        print 'No prob with conn'
> 
> >      except:
> 
> >        print "Error: Database connection failed. User name or Database name may be wrong"
> 
> >        return
> 
> >
> 
> >      #more code ...
> 
> > ----------------------------END OF PYTHON CODE----------------------------------
> 
> >
> 
> > Console output:
> 
> >
> 
> > --------------------------------CONSOLE OUTPUT----------------------------------
> 
> > No prob with conn
> 
> > --------------------------------END OF CONSOLE OUTPUT---------------------------
> 
> >
> 
> >
> 
> > Any ideas guys? This one is killing me.  I'm just learning Python but I imagine the problem to be something very easy for a seasoned python developer so any help would be strongly appreciated.
> 
> >
> 
> In the first example you're using positional arguments, whereas in the 
> 
> second example you're using keyword arguments. Are you sure that the 
> 
> positional arguments are in the correct order?
> 
> 
> 
> Try using keyword arguments in the first argument:
> 
> 
> 
>      cnxOMC = mysql.connector.connect(user=user, password=password, 
> 
> host='localhost', database=database)
> 
> 
> 
> It might also help if you print the repr of the arguments; that way 
> 
> you'll be able to see the difference between, say, 0 and "0".
> 
> 
> 
> On another point, using a 'bare' except ("except:") is virtually always 
> 
> a *bad* idea. It'll catch _all_ exceptions, including NameError, which 
> 
> could indicate a bug in your code. Catch only what you need to, only 
> 
> what you're expecting and can handle.

Thanks, I really don't know the difference between positional and keyboard arguments so I think I must do some python reading. I'm not really a python programmer (I'm a C, assembly, Java and C# programmer). Anyway the code is now working.

Thanks a lot to both of you.
Regards.