Hi, I'm experiencing a similar problem in my program (Sqlalchemy 0.8.4).
In my case no blob column is involved, the problem seems to be related to
presence of a foreign key in the target table. Here is the traceback of the
error:
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line 721,
in commit
self.transaction.commit()
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line 354,
in commit
self._prepare_impl()
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line 334,
in _prepare_impl
self.session.flush()
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line
1818, in flush
self._flush(objects)
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line
1936, in _flush
transaction.rollback(_capture_exception=True)
File "C:\Python27\lib\site-packages\sqlalchemy\util\langhelpers.py", line
58, in __exit__
compat.reraise(exc_type, exc_value, exc_tb)
File "C:\Python27\lib\site-packages\sqlalchemy\orm\session.py", line
1900, in _flush
flush_context.execute()
File "C:\Python27\lib\site-packages\sqlalchemy\orm\unitofwork.py", line
372, in execute
rec.execute(self)
File "C:\Python27\lib\site-packages\sqlalchemy\orm\unitofwork.py", line
525, in execute
uow
File "C:\Python27\lib\site-packages\sqlalchemy\orm\persistence.py", line
64, in save_obj
table, insert)
File "C:\Python27\lib\site-packages\sqlalchemy\orm\persistence.py", line
569, in _emit_insert_statements
execute(statement, params)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 662,
in execute
params)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 761,
in _execute_clauseelement
compiled_sql, distilled_params
File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 828,
in _execute_context
None, None)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line
1024, in _handle_dbapi_exception
exc_info
File "C:\Python27\lib\site-packages\sqlalchemy\util\compat.py", line 196,
in raise_from_cause
reraise(type(exception), exception, tb=exc_tb)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 824,
in _execute_context
context = constructor(dialect, self, conn, *args)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\default.py", line
446, in _init_compiled
self.__process_defaults()
File "C:\Python27\lib\site-packages\sqlalchemy\engine\default.py", line
821, in __process_defaults
val = self.get_insert_default(c)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\default.py", line
777, in get_insert_default
return self._exec_default(column.default, column.type)
File "C:\Python27\lib\site-packages\sqlalchemy\engine\default.py", line
761, in _exec_default
return self.fire_sequence(default, type_)
StatementError: 'SQLiteExecutionContext' object has no attribute
'fire_sequence' (original cause: AttributeError: 'SQLiteExecutionContext'
object has no attribute 'fire_sequence') u'INSERT INTO dataset (set_id,
user_id, label, set_table, nam_table, val_table, datasource, info) VALUES
(?, ?, ?, ?, ?, ?, ?, ?)' [{'info': None, 'user_id': 1, 'val_table':
u'val_table', 'label': u'tab1', 'nam_tab': u'nam_table', 'set_table':
u'tab1', 'datasource': None}]
The construct which causes the error is this:
dataset.append_constraint(sa.ForeignKeyConstraint([dataset.c.set_id],
[task.c.set_id]))
If I remove this line of code everything goes well (but of course I cannot
set up the relationship between the dataset table and the task table).
Any help is really appreciated.
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