In SqlAlchemy, how to ignore m2m relationship attributes when merge?

Posted by ablmf on Stack Overflow See other posts from Stack Overflow or by ablmf
Published on 2010-04-19T05:01:31Z Indexed on 2010/04/19 5:03 UTC
Read the original article Hit count: 257

Filed under:

sqlalchemy

|

python

There is a m2m relation in my models, User and Role.

I want to merge a role, but i DO NOT want this merge has any effect on user and role relation-ship. Unfortunately, for some complicate reason, role.users if not empty.

I tried to set role.users = None, but SA complains None is not a list.

At this moment, I use sqlalchemy.orm.attributes.del_attribute, but I don't know if it's provided for this purpose.

© Stack Overflow or respective owner

Related posts about sqlalchemy

sqlalchemy date type in 0.6 migration using mssql

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm connection to mssql server through pyodbc, via FreeTDS odbc driver, on linux ubuntu 10.04. Sqlalchemy 0.5 uses DATETIME for sqlalchemy.Date() fields. Now Sqlalchemy 0.6 uses DATE, but sql server 2000 doesn't have a DATE type. How can I make DATETIME be the default for sqlalchemy.Date() on sqlalchemy… >>> More
OperationalError "unable to open database file" processing query results with SQLAlchemy and SQLite3

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm running into this little problem that I hope is just a dumb user error. It looks like some sort of a size limit with a query to a SQLite database. I managed to reproduce the issue with an in-memory DB and a simple script shown below. I can make it work by either reducing the number of records… >>> More
Starter question of declarative style SQLAlchemy relation()

as seen on Stack Overflow - Search for 'Stack Overflow'
I am quite new to SQLAlchemy, or even database programming, maybe my question is too simple. Now I have two class/table: class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String(40)) ... class Computer(Base): __tablename__ = 'comps' … >>> More
Default class for SQLAlchemy single table inheritance

as seen on Stack Overflow - Search for 'Stack Overflow'
I've set up a single table inheritance, but I need a "default" class to use when an unknown polymorphic identity is encountered. The database is not in my control and so the data can be pretty much anything. A working example setup: import sqlalchemy as sa from sqlalchemy import orm engine = sa… >>> More
Batch select with SQLAlchemy

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a large set of values V, some of which are likely to exist in a table T. I would like to insert into the table those which are not yet inserted. So far I have the code: for value in values: s = self.conn.execute(mytable.__table__.select(mytable.value == value)).first() … >>> More

Related posts about python

unmet dependencies in Ubuntu 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried today to install a dvb-card on my Ubuntu 12.04 (Linux blauhai-linux 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux ). The installation failed with an error. After that, i tried to install python (it was already installed but i got this error): linux:~$… >>> More
How can I get sikuli-ide to work?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I installed sikuli-ide with sudo apt-get install sikuli-ide Everything was fine until I tried to start it from the terminal. I typed sikuli-ide But the only response I got was [info] locale: en_US The application was not started, furthermore there is no desktop file and sikuli-ide does not… >>> More
Getting PATH right for python after MacPorts install

as seen on Super User - Search for 'Super User'
I can't import some python libraries (PIL, psycopg2) that I just installed with MacPorts. I looked through these forums, and tried to adjust my PATH variable in $HOME/.bash_profile in order to fix this but it did not work. I added the location of PIL and psycopg2 to PATH. I know that Terminal is… >>> More
call python with system() in R to run a python script emulating the python console

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to pass a chunk of Python code to Python in R with something like system('python ...'), and I'm wondering if there is an easy way to emulate the python console in this case. For example, suppose the code is "print 'hello world'", how can I get the output like this in R? >>> print… >>> More
Python - Calling a non python program from python?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am currently struggling to call a non python program from a python script. I have a ~1000 files that when passed through this C++ program will generate ~1000 outputs. Each output file must have a distinct name. The command I wish to run is of the form: program_name -input -output -o1 -o2… >>> More