Say i have the following Users model-
class Users(Base):
__tablename__='users'
id=Column(Integer, primary=True)
friends=relationship(
'Users',
secondary='friend_associations',
primaryjoin='and_(FriendAssociations.user_id==Users.id,'
'FriendAssociations.pending==False)',
secondaryjoin='and_(FriendAssociations.friend_id==Users.id,'
'FriendAssociations.pending==False)',
uselist=True,
)
And the FriendAssociations model is-
class FriendAssociations(Base):
__tablename__='friend_associations'
id=Column(Integer, primary=True)
user_id=Column(ForeignKey('Users.id'), nullable=False)
friend_id=Column(ForeignKey('Users.id'), nullable=False)
pending=Column(Boolean, default=True)
__table_args__ = (UniqueConstraint(
'user_id','friend_id', name='uq_user_friend_id_pair'
),)
The target was, user A sends a friend request to user B. Until user B
accepts the request, the request stays as pending. When B accepts the
request, pending is False and one more friend_associations entry is created
on user B to state that user A is friend of user B and vice versa. The
problem is, i can do these things, but when i want to remove a user entry,
the database(i am using PostgreSQL) throws up error saying
friend_associations depends on the user(because the association entry isn't
deleted). As a result i can't delete any user entry.
So -
1. Is my solution to the problem correct?
2. If not, what should i do to correct it?
3. Please give basic query examples like adding, deleting friends and
user entries with such solution or mine.
Thanks in advance.
--
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.
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