我在我的项目中使用Flask-Sqlalchemy orm。
每当另一个表上有更新时，我必须在一个表中插入一个新对象。所以，我选择了models_committed signal.But，没有插入该对象。
@models_committed.connect_via(app)
def on_models_committed(sender, changes):
print "signal",changes
for obj, change in changes:
if obj.__table__.strip() == 'task':
print "works"
obj = TaskHistory(task_id=target.id, task_status_id=target.task_status_id, reason=target.reason)
print "History Object",obj
db.session.add(obj)
db.session.commit()
回溯：
简短版本：
**sqlalchemy.exc.InvalidRequestError
InvalidRequestError: This session is in 'committed' state; no further SQL can be emitted within this transaction.**
长版：
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask_debugtoolbar/__init__.py", line 125, in dispatch_request
return view_func(**req.view_args)
File "/usr/lib/python2.7/cProfile.py", line 149, in runcall
return func(*args, **kw)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/base.py", line 37, in inner
return f(self, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/base.py", line 37, in inner
return f(self, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/base.py", line 37, in inner
return f(self, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/base.py", line 37, in inner
return f(self, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/model/base.py", line 345, in edit
pk=self.get_pk(instance), instance=instance)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/base.py", line 169, in render
return render_template(template, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask/templating.py", line 128, in render_template
context, ctx.app)
File "/usr/local/lib/python2.7/dist-packages/flask/templating.py", line 110, in _render
rv = template.render(context)
File "/usr/share/pyshared/jinja2/environment.py", line 969, in render
return self.environment.handle_exception(exc_info, True)
File "/usr/share/pyshared/jinja2/environment.py", line 742, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/model/edit.html", line 3, in top-level template code
{% set name = admin_view.get_display_name() %}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/layout.html", line 21, in top-level template code
{% block page_body %}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/layout.html", line 70, in block "page_body"
{% block body %}{% endblock %}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/model/edit.html", line 26, in block "body"
{{ lib.render_form(form, extra(), admin_view.can_edit, admin_view.can_delete) }}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/_macros.html", line 192, in template
{{ render_formfield(form) }}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/_macros.html", line 180, in template
{{ render_ff(form._fields[field_name]) }}
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/templates/admin/_macros.html", line 142, in template
{{ ff(class=class) }}
File "/usr/local/lib/python2.7/dist-packages/wtforms/fields/core.py", line 139, in __call__
return self.widget(self, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/flask_superadmin/form.py", line 96, in __call__
return super(ChosenSelectWidget, self).__call__(field, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/wtforms/widgets/core.py", line 243, in __call__
for val, label, selected in field.iter_choices():
File "/usr/local/lib/python2.7/dist-packages/wtforms/ext/sqlalchemy/fields.py", line 108, in iter_choices
for pk, obj in self._get_object_list():
File "/usr/local/lib/python2.7/dist-packages/wtforms/ext/sqlalchemy/fields.py", line 101, in _get_object_list
self._object_list = list((text_type(get_pk(obj)), obj) for obj in query)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2404, in __iter__
return self._execute_and_instances(context)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2417, in _execute_and_instances
close_with_result=True)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2408, in _connection_from_session
**kw)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 843, in connection
close_with_result=close_with_result)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 847, in _connection_for_bind
return self.transaction._connection_for_bind(engine)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 298, in _connection_for_bind
self._assert_active()
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 192, in _assert_active
"This session is in 'committed' state; no further "
InvalidRequestError: This session is in 'committed' state; no further SQL can be emitted within this transaction.
你能协助我解决这个问题吗？
我正在使用的工具：Python 2.7，Flask，SqlAlchemy
答案 0 :(得分：0)
@models_committed.connect_via(app)
def on_models_committed(sender, changes):
db_name = app.config["DB_NAME"]
db_user = app.config["DB_USER"]
db_pwd = app.config["DB_PWD"]
conn = psycopg2.connect("dbname='%s' user='%s' host='localhost' password='%s'" %(db_name, db_user, db_pwd))
query = "INSERT INTO task_history(task_id, task_status_id, updated_on, updated_by, reason)" +\
"VALUES (%s, %s, '%s', %s, '%s')"
cur = conn.cursor()
for obj, change in changes:
if str(obj.__table__).strip() == 'task':
cur.execute(query % (obj.id, obj.task_status_id, "now()", 2, "Thats it"))
conn.commit()
我的解决方案（我已回答了我的问题）：
答案 1 :(得分：0)
这不是解决方案，你只是解决了这个问题。你应该看看为什么你在for循环中重新分配了obj。删除重新分配可能会解决您的问题。