catching SQLAlchemy exceptions

Question

What is the upper level exception that I can catch SQLAlechmy exceptions with ?

>>> from sqlalchemy import exc
>>> dir(exc)
[\'ArgumentError\',         


        

Answer 1

From the source:

The base exception class is SQLAlchemyError.

Answer 2

To catch any exception SQLAlchemy throws:

from sqlalchemy import exc
db.add(user)
try:
  db.commit()
except exc.SQLAlchemyError:
  pass # do something intelligent here

See help(sqlalchemy.exc) and help(sqlalchemy.orm.exc) for a list of possible exceptions that sqlalchemy can raise.

Answer 3

Depending on your version of SQLAlchemy (e.g. 1.0.4), you may need to do a little more to get to the base-SQLAlchemyError class:

from flask.ext.sqlalchemy import exc
exceptions = exc.sa_exc

try:
    my_admin = user_models.User('space cadet', active=True)
    db.session.add(my_admin)
    db.session.commit()
except exceptions.SQLAlchemyError:
    sys.exit("Encountered general SQLAlchemyError.  Call an adult!")

this is because sqlalchemy.orm.exc now has the stanza:

"""SQLAlchemy ORM exceptions."""
from .. import exc as sa_exc, util