Re: [sqlalchemy] Does anyone know how to handle "NoSuchColumnError"

[Mike Bayer]

On 5/3/15 2:01 AM, Ofir Herzas wrote:
Hi Michael,
Thank you very much for your fast response. I will give it a try.
I tried to remove unneeded stuff but I think that the problem is in 
the track_changes mixin as I never got this error before using it.
If you need more stuff or do find something, I'd be happy to know.

OK, passing "implicit_returning=False" to the Table objects created by 
the history mixin should fix it on your end.   I'll try to find some 
time to experiment with it.



BTW: for initialization, I use:

DB_URL="oracle://user:pass@url/db"
engine = create_engine(DB_URL, echo=False, pool_recycle=3600)
Session = scoped_session(sessionmaker(bind=engine, 
expire_on_commit=False))
session = tracked_session(Session())
Base = declarative_base()

Cheers,
Ofir

On Thursday, April 30, 2015 at 7:03:10 PM UTC+3, Michael Bayer wrote:



    On 4/30/15 11:00 AM, Ofir Herzas wrote:
    Hi,
    I'm using sqlalchemy 0.9.7 and cx_oracle 5.1.3 and every once in
    a while (inconsistent), I get the following error:

    Traceback (most recent call last):
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 1919, in flush
        self._flush(objects)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 2037, in _flush
        transaction.rollback(_capture_exception=True)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/util/langhelpers.py",
    line 60, in __exit__
        compat.reraise(exc_type, exc_value, exc_tb)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 2001, in _flush
        flush_context.execute()
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/unitofwork.py",
    line 372, in execute
        rec.execute(self)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/unitofwork.py",
    line 526, in execute
        uow
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/persistence.py",
    line 65, in save_obj
        mapper, table, insert)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/persistence.py",
    line 602, in _emit_insert_statements
        execute(statement, params)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 729, in execute
        return meth(self, multiparams, params)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/sql/elements.py",
    line 321, in _execute_on_connection
        return connection._execute_clauseelement(self, multiparams,
    params)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 826, in _execute_clauseelement
        compiled_sql, distilled_params
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 978, in _execute_context
        context._fetch_implicit_returning(result)
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/default.py",
    line 815, in _fetch_implicit_returning
        ipk.append(row[c])
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/result.py",
    line 331, in _key_fallback
        expression._string_or_unprintable(key))
    NoSuchColumnError: "Could not locate column in row for column
    't_shift_employee_change.id <http://t_shift_employee_change.id>'"
    [30/Apr/2015:15:55:17] EXCEPTION
    # ---- EXCEPTION DESCRIPTION BEGIN ---- #
    # ---- Type ---- #
    NoSuchColumnError
    # ---- Detail ---- #
    "Could not locate column in row for column
    't_shift_employee_change.id <http://t_shift_employee_change.id>'"
    # ---- Traceback ---- #
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 1919, in flush
        self._flush(objects)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 2037, in _flush
        transaction.rollback(_capture_exception=True)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/util/langhelpers.py",
    line 60, in __exit__
        compat.reraise(exc_type, exc_value, exc_tb)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
    line 2001, in _flush
        flush_context.execute()
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/unitofwork.py",
    line 372, in execute
        rec.execute(self)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/unitofwork.py",
    line 526, in execute
        uow
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/persistence.py",
    line 65, in save_obj
        mapper, table, insert)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/orm/persistence.py",
    line 602, in _emit_insert_statements
        execute(statement, params)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 729, in execute
        return meth(self, multiparams, params)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/sql/elements.py",
    line 321, in _execute_on_connection
        return connection._execute_clauseelement(self, multiparams,
    params)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 826, in _execute_clauseelement
        compiled_sql, distilled_params
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
    line 978, in _execute_context
        context._fetch_implicit_returning(result)
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/default.py",
    line 815, in _fetch_implicit_returning
        ipk.append(row[c])
    -
      File
    
"/opt/enigmai/ve/python-2.7.6/lib/python2.7/site-packages/sqlalchemy/engine/result.py",
    line 331, in _key_fallback
        expression._string_or_unprintable(key))

    # ---- EXCEPTION DESCRIPTION END ---- #

    I saw several posts about this issue but I didn't find a solution.
    Restarting my service seems to fix the issue for a while.

    BTW: This error is linked to a mixin class I've created for
    track-changes based on the version mixin from /

    
http://docs.sqlalchemy.org/en/latest/_modules/examples/versioned_history/history_meta.html
    
<http://docs.sqlalchemy.org/en/latest/_modules/examples/versioned_history/history_meta.html>

    /

    this error refers to a wide variety of situations where the ORM is
    running a query that is failing to compose correctly.  It's a bug
    in SQLAlchemy.  That you are getting this within an INSERT
    statement from the RETURNING clause in oracle strongly suggests
    this is a bug in the Oracle dialect.   If you can post minimal
    mappings and the stack trace here as a bug report that would be
    very helpful.

    Note also that the Oracle dialect doesn't do very well with
    composite primary keys in conjunction with RETURNING. There may
    have been some limitations I came across in my testing here, so
    there is a note at
    http://docs.sqlalchemy.org/en/rel_1_0/dialects/oracle.html#returning-support
    
<http://docs.sqlalchemy.org/en/rel_1_0/dialects/oracle.html#returning-support>
    regarding this.     While I still want to know how you're getting
    exactly this kind of error since it would be nice to anticipate it
    better, the section here illustrates the
    implicit_returnining=False flag that would resolve these errors
    you're getting.



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