[sqlalchemy] Re: How to diagnose a transaction hang problem?
Thanks a lot! I tried pg_top and found locks been hold by idle transaction, and then I found that I forgot to close a session! On Jan 30, 9:43 am, Gunnlaugur Briem gunnlau...@gmail.com wrote: Another quick way of troubleshooting hangs is the tool pg_top, in which you might see a process in the state “Idle in transaction”. This state means that some database operations have been performed in a transaction on that connection but the transaction has not yet been committed. Those database operations will have been granted locks, for which your stalled session is waiting. Behind this idle-in-transaction connection might be another SQLAlchemy session that you neglected to commit or close. That's a common way for this situation to come up. You can see the locks held by the connection using pg_top (hit L), or you can find them with pg_locks as Alex mentioned. These locks may give you a clue as to where in your code that other session was created, helping you track down the bug to correct. To avoid creating cases like this, I try to be careful about session objects: I never store them (keep them on the stack, i.e. as local variables and function arguments), and I always create and close them using a construct like this: from contextlib import closing with closing(Session()) as session: do_stuff() session.commit() if I want to Note that sessions are not the same as DB connections (which are pooled further down in the layers of stuff going on), you gain nothing by storing and reusing them, and you risk creating cases like this. Per the docs, “Sessions are very inexpensive to make, and don’t use any resources whatsoever until they are first used...so create some!” (and close and discard them happily). - G. On Jan 29, 2:13 pm, Alex Brasetvik a...@brasetvik.com wrote: On Jan 29, 2010, at 15:01 , 一首诗 wrote: What might cause this kind of problem? Possibly waiting on locks. Do you have any concurrent transactions modifying the same data? When the problem appears, run `select * from pg_stat_activity` to see whether there are locking issues. To see the locks involved, run `select * from pg_locks`. -- Alex Brasetvik -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] Re: How to diagnose a transaction hang problem?
Your advice sound reasonable. That means I have check the transaction **before** the hanged commit, maybe I forgot to commit or close a session at that time. On Jan 31, 7:55 am, Gunnlaugur Briem gunnlau...@gmail.com wrote: You probably don't have to add locks in your code. The database system takes locks on behalf of your code (in operations initiated by your code) as necessary to ensure transactional consistency. That's one of the benefits of an RDBMS. What you do have to do is to make sure that those database locks don't stay around forever (blocking other transactions). That happens when you forget to complete (commit or rollback/close) the transaction that creates them. If it eventually completes (either way), then things will work fine for the most part --- and at least not hang. (There is a lot more to this; you should read up on transactions and locks, it's fascinating stuff. But your immediate problem is very likely just a session/connection that you forget to close.) Regards, - Gulli On Jan 30, 4:53 am, 一首诗 newpt...@gmail.com wrote: Yeah， there might be another transaction modifying the same data (actually the same line of data in database). But I didn't expect that might cause problem before! Oh, if that's true, then I have to add some lock in my code to avoid that. That's a big problem. On Jan 29, 10:13 pm, Alex Brasetvik a...@brasetvik.com wrote: On Jan 29, 2010, at 15:01 , 一首诗 wrote: What might cause this kind of problem? Possibly waiting on locks. Do you have any concurrent transactions modifying the same data? When the problem appears, run `select * from pg_stat_activity` to see whether there are locking issues. To see the locks involved, run `select * from pg_locks`. -- Alex Brasetvik -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] How to diagnose a transaction hang problem?
Today I met a strange problem with SqlAlchemy and Postgresql. The code is like this: def update_user(user_id, sess): user = sess.query(User).get(user_id).one() user.last_activity_time = datetime.now() session.commit() It hangs here forever. In the code above, sess is a scoped session. I don't have any clue of what happened. In most case the code above worked. But suddenly it hangs and any other thread that want to talk to database after that line is hit are also hanged. I have to kill the process. It does not look like that this a problem of database since after I restart my application, it works again. What might cause this kind of problem? -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] Re: How to diagnose a transaction hang problem?
Yeah， there might be another transaction modifying the same data (actually the same line of data in database). But I didn't expect that might cause problem before! Oh, if that's true, then I have to add some lock in my code to avoid that. That's a big problem. On Jan 29, 10:13 pm, Alex Brasetvik a...@brasetvik.com wrote: On Jan 29, 2010, at 15:01 , 一首诗 wrote: What might cause this kind of problem? Possibly waiting on locks. Do you have any concurrent transactions modifying the same data? When the problem appears, run `select * from pg_stat_activity` to see whether there are locking issues. To see the locks involved, run `select * from pg_locks`. -- Alex Brasetvik -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] What might cause QueuePool limit of size 5 overflow 10 reached?
I occasionally got QueuePool limit of size 5 overflow 10 reached. I don't call session.close() after I don't need them. Because I think GC will do that. But now, it seems that I am losting connections somewhere. Should I call session.close after I use them? Should I use try.. finally... to make sure session.close is called? --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Should we separate business logic and ORM mapping classes.
Hi, Usually, I only use ORM, like pyamf just as an abstraction layer of database. So these mapping objects I wrote only contains data but not behavior. For example, if I have a class User, I would write another class UserManager which with a methods like addUser, delUser. But recently I am thinking of moving these methods to User. That sounds more OO style. What's your opinion? What's the benefits and problems of this style? --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Any one tried to use SqlAlchemy with XML RPC?
The actual reason why I need XML RPC is not because I need RPC.
Actaully I need XML.
I need to represent SA objects in text format so systems using
programming language other than python could decode them.
On Mar 19, 1:27 pm, Andreas Jung li...@zopyx.com wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 19.03.2009 5:24 Uhr, 一首诗 wrote:
This is my ORM class definition:
#=
class User(Base):
__tablename__ = 'b_taa_user'
user_id = Column(Integer, primary_key=True, autoincrement=True,
nullable=False) # 用户ID
user_name = Column(Unicode(255), unique=True, nullable=False,
server_default=) # 用户名称
user_password = Column(Unicode(255), nullable=False,
server_default=) # 用户密码
email = Column(Unicode(255), nullable=False, server_default=) # 邮
箱
mobile = Column(Unicode(255), nullable=False, server_default=) #
手机
phone = Column(Unicode(255), nullable=False, server_default=) # 电
话
def __init__(self, user_name = ):
self.user_name = username
#=
I made some debug by the code below:
#=
#!/usr/bin/python
import xmlrpclib
from blf.model import User
u = User('333')
s = xmlrpclib.dumps((u,), methodresponse=True, allow_none=True)
print s
#=
Finally, I found that the first problem is : xmlrpclib only serialize
type *instance*.
But to my surprise, when I check type of u, it's a *class* object.
Don't know why ...
Sending mapped instances over XMLRPC is basically nonsense. XMLRPC is
designed for transporting elementary datatypes over the wire in order to
invoke a remote method. It is not designed for sending instances of some
class and not for sending Python pickles. No idea what you are trying to
accomplish. Consider converting a mapped instance to dict and sending
this dict serialized in JSON format to a remote XMLRPC server.
- -aj
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[sqlalchemy] Re: Any one tried to use SqlAlchemy with XML RPC?
This is my ORM class definition:
#=
class User(Base):
__tablename__ = 'b_taa_user'
user_id = Column(Integer, primary_key=True, autoincrement=True,
nullable=False) # 用户ID
user_name = Column(Unicode(255), unique=True, nullable=False,
server_default=) # 用户名称
user_password = Column(Unicode(255), nullable=False,
server_default=) # 用户密码
email = Column(Unicode(255), nullable=False, server_default=) # 邮
箱
mobile = Column(Unicode(255), nullable=False, server_default=) #
手机
phone = Column(Unicode(255), nullable=False, server_default=) # 电
话
def __init__(self, user_name = ):
self.user_name = username
#=
I made some debug by the code below:
#=
#!/usr/bin/python
import xmlrpclib
from blf.model import User
u = User('333')
s = xmlrpclib.dumps((u,), methodresponse=True, allow_none=True)
print s
#=
Finally, I found that the first problem is : xmlrpclib only serialize
type *instance*.
But to my surprise, when I check type of u, it's a *class* object.
Don't know why ...
On Mar 18, 6:50 pm, Noah Gift noah.g...@gmail.com wrote:
On Wed, Mar 18, 2009 at 11:46 PM, 一首诗 newpt...@gmail.com wrote:
Hi,
I am trying to pass SqlAlchemy objects to client with XML RPC, but it
seems that that's not very easy.
It depends on what you are trying to do, and what error messages you are
getting, for anyone to help. I am using XML RPC with SQLAlchemy right now,
and I am, in fact, passing objects in. I wrote a metaclass that calls back
to XML RPC, and takes the ugly nested dictionary and returns back a nifty
class pre-populated with attributes I need to fill out. When I set each
attribute, it then populates __dict__. At that point, I simply pass that
back to XML RPC. Works great.
The reason why I have to do this is that my client is written in
javascript and running on a web page. So it could not use anything
other than text based protocols, such as XML RPC, SOAP, or JSON.
I tried pyamf, and it works pretty good with SA, but I can't use amf
with javascript.
Is there any possible solutions with my problem?
--
Cheers,
Noah
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[sqlalchemy] Re: Using sqlalchemy in twisted.
Hi Jeff, In my project I use the *model* to indicate an instance of Database. I don't really need multiple instances of Database. But when I wrote unit test, I always create an new one database in setup, which create a new sqlite in memory database to avoid conflicts between test cases. About the trick to make *sess* a keywork parameter, that's really clever! Thanks a lot! On Mar 11, 9:05 pm, Jeff FW jeff...@gmail.com wrote: Logging SA objects *after* the session is gone will always be a problem, unless you make sure to detach all of them from the session. I'd just log the original request, instead. In my case, I have to convert all of my SA objects to something Perspective Broker understands, so I actually log those *after* that, as they're no longer part of the session--but I'm not sure if you can do that in your case. As for the decorator--I got a little confused with your names--you call it model in your decorator, but it's really an instance of Database when it gets passed in as self. One way to get rid of that parameter would be to make sess a keyword argument, like so: def wrapper(*args, **kw): sess = model.Session() try: return f(sess=sess, *args, **kw) and then change your method: def _getObjectById(self, klass, id, sess=None): return sess.query(klass).get(id) That way, self will get passed in *args with no problem. Are you planning to have multiple instances of your Database class? If not, I'd suggest changing everything in it into class methods, so that way you can call it *without* an instance at all, and don't have to worry about connecting to the database multiple times by accident. Just a thought. -Jeff On Mar 10, 10:38 am, 一首诗 newpt...@gmail.com wrote: Hi Jeff, Thanks for your kind suggestion. I first add some log decorators, but i found when it might cause to print sqalchemy objects which has not been bound to any session. And I am not quite sure about how to make the decorator mor genreal. Actually, I think I must use model as the first parameter because as a instance method, _getObjectById require the first parameter to be self. Can you write a few lines of code to show your suggestion? On Mar 8, 5:06 am, Jeff FW jeff...@gmail.com wrote: That's pretty similar to what I do, actually, if a bit simpler (but that's good!) One suggestion would be to throw an except (maybe for the base SQLAlchemy exception class) in your try block, otherwise you run the risk of things dying in an ugly way. I'm not familiar with pyamf, so I don't know how it would handle errors, but twisted usually carries on as if nothing happens. Also, I'd make the decorator a bit more general--don't put the model argument in wrapper(). Put sess first, then take *args and **kwargs, and pass those right to the inner function f(). That way you can reuse it for anything that requires a DB session. Other things you could add (if so inclined) are decorators for logging and other types of error handling (like catching IntegrityErros thrown by duplicates.) I do those things, but I might be a bit OCD :-) -Jeff On Mar 7, 1:41 am, 一首诗 newpt...@gmail.com wrote: Hi, Thanks for your reply. I'm using it the way like you. The only difference is that I am using pyamf instead of PB. On every request, I delegate required db operations to a class called Database, similar to these code below. I used to use scope_session instead of create and close session every time. But as I said in my earlier mails, they don't work. These code below seems to work right now. But if you have more suggestion, I will be very thankful. #= def require_session(f): '''create and close session for each synchronous method''' def wrapper(model, *args, **kw): sess = model.Session() try: return f(model, sess, *args, **kw) finally: sess.close() return wrapper class Database() def __init__(self, conn_str): self.conn_str = conn_str self.engine = create_engine(self.conn_str, echo=False) self.Session = sessionmaker(bind = self.engine, expire_on_commit=False) def getObjectById(self, klass, id): return threads.deferToThread(self._getObjectById, klass, id) @require_session def _getObjectById(self, sess, klass, id): return sess.query(klass).get(id) #= On Mar 6, 5:44 am, Jeff FW jeff...@gmail.com wrote: Don't use scoped_session--you'll run into problems no matter what you do. I'm using Perspective Broker from Twisted with SQLAlchemy. I make sure to create and commit/rollback a session for *every* PB request. It works perfectly, and that's the only way I
[sqlalchemy] Re: Using sqlalchemy in twisted.
Hi Jeff, Thanks for your kind suggestion. I first add some log decorators, but i found when it might cause to print sqalchemy objects which has not been bound to any session. And I am not quite sure about how to make the decorator mor genreal. Actually, I think I must use model as the first parameter because as a instance method, _getObjectById require the first parameter to be self. Can you write a few lines of code to show your suggestion? On Mar 8, 5:06 am, Jeff FW jeff...@gmail.com wrote: That's pretty similar to what I do, actually, if a bit simpler (but that's good!) One suggestion would be to throw an except (maybe for the base SQLAlchemy exception class) in your try block, otherwise you run the risk of things dying in an ugly way. I'm not familiar with pyamf, so I don't know how it would handle errors, but twisted usually carries on as if nothing happens. Also, I'd make the decorator a bit more general--don't put the model argument in wrapper(). Put sess first, then take *args and **kwargs, and pass those right to the inner function f(). That way you can reuse it for anything that requires a DB session. Other things you could add (if so inclined) are decorators for logging and other types of error handling (like catching IntegrityErros thrown by duplicates.) I do those things, but I might be a bit OCD :-) -Jeff On Mar 7, 1:41 am, 一首诗 newpt...@gmail.com wrote: Hi, Thanks for your reply. I'm using it the way like you. The only difference is that I am using pyamf instead of PB. On every request, I delegate required db operations to a class called Database, similar to these code below. I used to use scope_session instead of create and close session every time. But as I said in my earlier mails, they don't work. These code below seems to work right now. But if you have more suggestion, I will be very thankful. #= def require_session(f): '''create and close session for each synchronous method''' def wrapper(model, *args, **kw): sess = model.Session() try: return f(model, sess, *args, **kw) finally: sess.close() return wrapper class Database() def __init__(self, conn_str): self.conn_str = conn_str self.engine = create_engine(self.conn_str, echo=False) self.Session = sessionmaker(bind = self.engine, expire_on_commit=False) def getObjectById(self, klass, id): return threads.deferToThread(self._getObjectById, klass, id) @require_session def _getObjectById(self, sess, klass, id): return sess.query(klass).get(id) #= On Mar 6, 5:44 am, Jeff FW jeff...@gmail.com wrote: Don't use scoped_session--you'll run into problems no matter what you do. I'm using Perspective Broker from Twisted with SQLAlchemy. I make sure to create and commit/rollback a session for *every* PB request. It works perfectly, and that's the only way I was really able to get it to work in all cases. Assuming you're using Twisted in a similar way, you could write a simple decorator to wrap any functions that need a database session in the begin/commit stuff as necessary. If you can give more details of how you're using Twisted, I might be able to offer some more insight. -Jeff On Mar 5, 12:33 am, 一首诗 newpt...@gmail.com wrote: I'm not quite sure, but I think I'm pretty careful of sharing objects between threads. 1st, I only cached as few as possible orm objects. I tried to detach them, but I found that if I detach them, I can't access any of their fields any more. 2nd, I create new orm objects based on client request, pass them to class Database and then merge them to scoped sessions, change, commit and then discard these objects. 3rd, I switch to sqlite frequently to check if there is any database operation outside Database, because sqlite doesn't allow multi-thread access. Actually it seems to work until 2 or 3 days ago suddenly cases hang the server. Ah, as I've already written lots of code in ORM, I think maybe I should try to change Database to use a dedicated thread to handle all database operations. That might be a bottle neck of my application, but I really can't give up orm as these mapper classes are used everywhere in my application. On Mar 4, 7:26 pm, 一首诗 newpt...@gmail.com wrote: Hi, all I am using sqlalchemy in twisted in my project in the way below. Defer any database operation so the twisted's main thread won't be blocked. And I use scoped_session, so that sessions won't have to be created again and again. == class Database() def __init__(self, conn_str): self.conn_str = conn_str
[sqlalchemy] Re: Using sqlalchemy in twisted.
I'm not quite sure, but I think I'm pretty careful of sharing objects between threads. 1st, I only cached as few as possible orm objects. I tried to detach them, but I found that if I detach them, I can't access any of their fields any more. 2nd, I create new orm objects based on client request, pass them to class Database and then merge them to scoped sessions, change, commit and then discard these objects. 3rd, I switch to sqlite frequently to check if there is any database operation outside Database, because sqlite doesn't allow multi-thread access. Actually it seems to work until 2 or 3 days ago suddenly cases hang the server. Ah, as I've already written lots of code in ORM, I think maybe I should try to change Database to use a dedicated thread to handle all database operations. That might be a bottle neck of my application, but I really can't give up orm as these mapper classes are used everywhere in my application. On Mar 4, 7:26 pm, 一首诗 newpt...@gmail.com wrote: Hi, all I am using sqlalchemy in twisted in my project in the way below. Defer any database operation so the twisted's main thread won't be blocked. And I use scoped_session, so that sessions won't have to be created again and again. == class Database() def __init__(self, conn_str): self.conn_str = conn_str self.engine = create_engine(self.conn_str, echo=False) self.Session = scoped_session(sessionmaker(bind = self.engine, expire_on_commit=False)) def getObjectById(self, klass, id): return threads.deferToThread(self._getObjectById, klass, id) def _getObjectById(self, klass, id): sess = self.Session() return sess.query(klass).get(id) == The code doesn't work. When I limit the thread numbers to 1 reactor.suggestThreadPoolSize(1) Everything goes fine. Other wise the server would be blocked and must be killed by kill 9 The result conflicts with my understanding of sqlalchemy. Since I don't share any object between threads, there should be no problem! Ah It always have risk to use something you haven't tried before --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] An instance's attributes lost while the other updated.
Hi all, I have 2 user instance in a session and after I have update one of it like this --- u = session.merge(u) session.commit session.refresh(u) --- Later, I found that another instance of the same class type in the session's attributes was cleared, and triggered a database query. (I found this because I am using sqlite, which forbids access the same database in more than one thread) I will make some debug to find out what happened. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] What's the use of expunge?
The document says: Expunge removes an object from the Session, sending persistent instances to the detached state, and pending instances to the transient state: I hoped that if an instance was expunged from a session, I might use it safely as a container of some temp data without fearing trigger any database query. But I found that if an object is 'expunge'd , it's properties will not be accessible anymore. So, when should we use expunge? Or it is kept for sqlalchemy inner use only? --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: An instance's attributes lost while the other updated.
A little more code to explain: Before commit, print u2 doesn't do trigger query. After commit, print u2 trigger a query, even if it has different primary key with u1. So this means : when u update one instance, the other instance of the same type will be in expired state. ## u1 = session.merge(u1) print -- print u2 session.commit() print -- print us ## On Feb 26, 2:17 pm, 一首诗 newpt...@gmail.com wrote: Hi all, I have 2 user instance in a session and after I have update one of it like this --- u = session.merge(u) session.commit session.refresh(u) --- Later, I found that another instance of the same class type in the session's attributes was cleared, and triggered a database query. (I found this because I am using sqlite, which forbids access the same database in more than one thread) I will make some debug to find out what happened. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] How to write a self 2 self relationship?
I tried to write : # class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String) fullname = Column(String) password = Column(String) sons = relation(User, order_by=User.id, backref=parent) # But the as 'User' is not defined at the line ... relation ... is processed, the code above doesn't work. So, does sqlalchemy support self 2 self relationship ? If the answer is YES, how to do it? --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: How to write a self 2 self relationship?
Like this ?
class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
name = Column(String)
fullname = Column(String)
password = Column(String)
sons = relation('User', order_by='User.id', backref=parent)
I got an Exception:
sqlalchemy.exc.ArgumentError: Could not determine join condition
between parent/child tables on relation User.sons. Specify a
'primaryjoin' expression. If this is a many-to-many relation,
'secondaryjoin' is needed as well.
On Feb 16, 5:08 pm, a...@svilendobrev.com wrote:
put it as text, it will be eval()'uated later
On Monday 16 February 2009 10:57:11 一首诗 wrote:
I tried to write :
#--
-- class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
name = Column(String)
fullname = Column(String)
password = Column(String)
sons = relation(User, order_by=User.id, backref=parent)
#--
--
But the as 'User' is not defined at the line ... relation ... is
processed, the code above doesn't work.
So, does sqlalchemy support self 2 self relationship ?
If the answer is YES, how to do it?
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[sqlalchemy] Problem of Unicode Strings
Hi all, I'm using sqlalchemy as my ORM library and it works fines until today one of my test case fail === sqlalchemy.exc.ProgrammingError: (ProgrammingError) You must not use 8- bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings. u'INSERT INTO b_taa_role (role_name, activity, grantable, hierarchy, creator, related_smf, related_domain, priority) VALUES (?, ?, ?, ?, ?, ?, ?, ?)' ['\xe7\xae\xa1\xe7\x90\x86\xe5\x91\x98', None, None, None, None, None, None, 0] === The problem is : it only fails on one system. I've test the case in 3 computer, 2 ubuntu and 1 ubuntu server. It only fails on ubuntu server edition. The locale setting, python version, and sqlalchemy version is identical! As the final running environment is not decided yer, I am afraid this will be a big problem. I have considered to use unicode every where, but the problem is, most of the data will retrieved will be in utf8. So if I choose unicode, I have to translate every string parameter. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] You must not use 8-bit bytestrings ??
Hi all, I'm using sqlalchemy as my ORM library and it works fines until today one of my test case fail === sqlalchemy.exc.ProgrammingError: (ProgrammingError) You must not use 8- bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings. u'INSERT INTO b_taa_role (role_name, activity, grantable, hierarchy, creator, related_smf, related_domain, priority) VALUES (?, ?, ?, ?, ?, ?, ?, ?)' ['\xe7\xae\xa1\xe7\x90\x86\xe5\x91\x98', None, None, None, None, None, None, 0] === The problem is : it only fails on one system. I've test the case in 3 computer, 2 ubuntu and 1 ubuntu server. It only fails on ubuntu server edition. The locale setting, python version, and sqlalchemy version is identical! As the final running environment is not decided yer, I am afraid this will be a big problem. I have considered to use unicode every where, but the problem is, most of the data will retrieved will be in utf8. So if I choose unicode, I have to translate every string parameter. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
