Hi, There's nothing that could cause the problem you describe in the example you provide maybe the guilty lines where not included.
The easier way to go should be to step by step reproduce your model structure until you face the problem you describe and then post an example code : http://stackoverflow.com/help/mcve. Regards Gaston Le 07/02/2018 à 12:09, Sven a écrit : > Hello everybody, > > Today, I have a strange problem regarding relationships. > > My project contains already several relationships and until now, I > never had any problem with these. But now, when I try to add a new > relationship between two classes, the entire program suddenly crashes > without displaying any error message. It looks like an infinite loop. > > I am sadly not able to reproduce the problem in a small example. > > I have a lot of classes with several relationships and the > informations are sometimes redundant and not optimized. For example: > > Player has a relationship with Race. > Race has a relationship with Skeleton. > Player has a relationship with Skeleton. > > It means that the Skeleton is also present in Player while the > Skeleton may also be accessible via Race... > > This is due to the fact that I am working from an existing project > whose save system was based on Pickle. > > Let's take the following example and let's assume that it reflects my > problem and crashes. > > | > classPlayer(Base): > > __tablename__ ='player' > id =Column(Integer,primary_key=True) > > id_weapon =Column(Integer,ForeignKey('weapon.id')) > weapon =relationship("Weapon",back_populates="players") > > id_room =Column(Integer,ForeignKey('room.id')) > room =relationship("Room",back_populates="players") > > ...other relationships > > classWeapon(Base): > > __tablename__ ='weapon' > id =Column(Integer,primary_key=True) > > players =relationship("Player",back_populates="weapon") > > ...other relationships > > > def__init__(arg1,arg2): > print("I will never be executed.") > ...some code > > classRoom(Base): > > __tablename__ ='room' > id =Column(Integer,primary_key=True) > > players =relationship("Player",back_populates="room") > > > ...other relationships > | > > > > I tried to determine which line makes the whole thing crashes and it > happens when I try to do this: > > *w = Weapon(arg1, arg2)* > > What is strange is that the __init__ is not executed. It crashes > between the call *Weapon(arg1, arg2)* and the __init__. The print > function*print("I will never be executed.")* will for example not be > executed. > > And I have just one __init__ in this class. > > > When I delete one of the relationships in the class Weapon, everything > works fine. > > > My hypothesis is that SQLAlchemy try to do something with > relationships when Weapon(arg1, arg2) is executed and for some > reasons, it crashes. Like I said, my relationships network is a bit > strange and absolutly not optimized. Is it possible that the > relationships and the back_populates are causing Infinite Loops ? > > Has someone already see that ? How could I learn more about the > problem and figure out what SQLALchemy is trying to do and where it > crashes ? > > Thank you. > > > Sven > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google > Groups "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to sqlalchemy+unsubscr...@googlegroups.com > <mailto:sqlalchemy+unsubscr...@googlegroups.com>. > To post to this group, send email to sqlalchemy@googlegroups.com > <mailto:sqlalchemy@googlegroups.com>. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
