[sqlalchemy] Re: sqlalchemy exceptions
On May 8, 2007, at 1:23 PM, noah.gift wrote: I am trying to use the following code to handle an exception in Turbogears, but it does not grab the SQLError: please note I did a: from sqlalchemy.exceptions import SQLError def save(self, name=None, email=None, password=None, password_confirm=None, **kw): try: u = User(user_name=name, display_name=name, email=email, password=password) raise redirect(/registered) except SQLError: flash(That account already exists.) i think youre confusing a pattern from SQLObject here. creating a new object doesnt write any changes to the database in sqlalchemy. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: sqlalchemy exceptions
On May 8, 1:58 pm, Michael Bayer [EMAIL PROTECTED] wrote: On May 8, 2007, at 1:23 PM, noah.gift wrote: I am trying to use the following code to handle an exception in Turbogears, but it does not grab the SQLError: please note I did a: from sqlalchemy.exceptions import SQLError def save(self, name=None, email=None, password=None, password_confirm=None, **kw): try: u = User(user_name=name, display_name=name, email=email, password=password) raise redirect(/registered) except SQLError: flash(That account already exists.) i think youre confusing a pattern from SQLObject here. creating a new object doesnt write any changes to the database in sqlalchemy. Your right. I wasn't sure of how much magic was occuring with Turbogears, but I really do like that I have to be explicit even inside of Turbogears. Forgive the dumb question, but what is the proper SQLAlchemy recommended way to deal with a situation like this. Should I see if the object already exists first, or be lazy and try to write to the database and attempt to catch the exception. I love to read, so if you can point me to some examples on situations like this it would be very helpful. Noah --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: sqlalchemy exceptions
Forgive the dumb question, but what is the proper SQLAlchemy recommended way to deal with a situation like this. Should I see if the object already exists first, or be lazy and try to write to the database and attempt to catch the exception. Good question. Personally I think that this Exception is common enough that you should check for it rather than catch it. But if you stick with what you have, I believe you will catch the error by adding something like this in your try statement: session.save(u) session.flush() I love to read, so if you can point me to some examples on situations like this it would be very helpful. Not sure if this is what you mean, but here is a very good SA tutorial: http://www.rmunn.com/sqlalchemy-tutorial/tutorial.html --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: sqlalchemy exceptions
On May 8, 2007, at 5:45 PM, noah.gift wrote: On May 8, 1:58 pm, Michael Bayer [EMAIL PROTECTED] wrote: On May 8, 2007, at 1:23 PM, noah.gift wrote: I am trying to use the following code to handle an exception in Turbogears, but it does not grab the SQLError: please note I did a: from sqlalchemy.exceptions import SQLError def save(self, name=None, email=None, password=None, password_confirm=None, **kw): try: u = User(user_name=name, display_name=name, email=email, password=password) raise redirect(/registered) except SQLError: flash(That account already exists.) i think youre confusing a pattern from SQLObject here. creating a new object doesnt write any changes to the database in sqlalchemy. Your right. I wasn't sure of how much magic was occuring with Turbogears, but I really do like that I have to be explicit even inside of Turbogears. Forgive the dumb question, but what is the proper SQLAlchemy recommended way to deal with a situation like this. Should I see if the object already exists first, or be lazy and try to write to the database and attempt to catch the exception. I love to read, so if you can point me to some examples on situations like this it would be very helpful. Well, my style would be to just query the database first, then if row exists just report to the user. since if you wait for an exception, you have to inspect the exception itself to check that its the key already exists error...and those errors will be different depending on the particular database in use. Unfortuantely DBAPI doesnt specify any standardized way to get at error codes and SA doesnt have any kind of error categorizing logic...so its a little bit of a guessing game. also you might want to have several operations related to creating a new user all within a single transaction which means catching the exception also means you have to roll back the transaction, making it more inconvenient to use exception catching as a check if the user exists type of function. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
