[sqlalchemy] Result of a table.update()
Hi All I'm using 0.6.4 under Windoze with MySQL, Python 2.6.4 and I had code that I thought worked before (0.6.3) - which appeared to break due to this issue.. I could be wrong on this point so I'll just get to the crux of the matter... I have a result = table.update(whereClause, values=someValuesDict).execute() The table is updated correctly, however, the resultproxy object I receive as 'result' appears to have no members. If I fetchone() or fetchall() I simply get a None result. Is this correct? If this IS correct, how is the best way to tell if the update was a success? I tried putting bad data in the whereClause and it simply did nothing to the database, but my resultproxy was the same. No Exceptions raised in either case? Please enlighten me.. Cheers Warwick Warwick Prince Managing Director mobile: +61 411 026 992 skype: warwickprince phone: +61 7 3102 3730 fax: +61 7 3319 6734 web: www.mushroomsys.com -- 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] Attribute overriding in mixin inheritance hierarchy
Hi all,
I am using declarative to model an existing object hierarchy where
there is an
abstract part that i model as an hierarchy of mixins and a concrete
part where
i use joined-table inheritance.
I have a problem when there is attributes with the same name, one
overriding
the other, in the abstract mixin hierarchy. Maybe I am doing something
wrong
so suggestions for how to implement this is most welcome.
Sample code:
import unittest
from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, String, Integer, Boolean
Base = declarative_base()
class AbstractA(object):
AttrA = Column(String(50))
def __init__(self, AttrA=AttrA):
self.AttrA = AttrA
class AbstractB(AbstractA):
AttrA = Column(String(50), primary_key=True)
def __init__(self, AttrA, **kwargs):
AbstractA.__init__(self, **kwargs)
self.AttrA = AttrA
class Concrete(Base, AbstractB):
__tablename__ = 'Concrete'
AttrB = Column(Boolean)
def __init__(self, AttrB, **kwargs):
AbstractB.__init__(self, **kwargs)
self.AttrB = AttrB
class TestAttributeOverriding(unittest.TestCase):
def testAttributeOverriding(self):
concrete = Concrete(AttrB = False, AttrA=0)
self.session.add(concrete)
self.session.commit()
assert len(self.session.query(Concrete).all()) == 1
def setUp(self):
self.engine = create_engine('sqlite:///:memory:', echo = True)
Session = sessionmaker(bind = self.engine)
self.session = Session()
self.metadata = Base.metadata
self.metadata.create_all(self.engine)
def tearDown(self):
self.metadata.drop_all(self.engine)
self.session.close()
This would fail with could not assemble any primary key columns for
mapped
table unless i apply the small patch below, which makes it work as i
would
expect (although i don't know if this is how it is intended to be):
--- /usr/lib/python2.6/site-packages/sqlalchemy/ext/
declarative.py
2010-09-07 19:05:34.0 +0200
+++ lib/python2.6/site-packages/SQLAlchemy-0.6.4-
py2.6.egg/sqlalchemy/ext/declarative.py2010-10-21
19:58:15.863671633
+0200
@@ -936,11 +936,13 @@
'__table__' in dict_ and
name in dict_['__table__'].c
):
-potential_columns[name] = \
-column_copies[obj] = \
-obj.copy()
-column_copies[obj]._creation_order = \
-obj._creation_order
+if name not in potential_columns:
+potential_columns[name] = \
+column_copies[obj] = \
+obj.copy()
+column_copies[obj]._creation_order =
\
+obj._creation_order
+
elif isinstance(obj, MapperProperty):
raise exceptions.InvalidRequestError(
Mapper properties (i.e. deferred,
---
Oystein
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Re: [sqlalchemy] Attribute overriding in mixin inheritance hierarchy
On Oct 21, 2010, at 2:39 PM, oystein wrote:
Hi all,
I am using declarative to model an existing object hierarchy where
there is an
abstract part that i model as an hierarchy of mixins and a concrete
part where
i use joined-table inheritance.
I have a problem when there is attributes with the same name, one
overriding
the other, in the abstract mixin hierarchy. Maybe I am doing something
wrong
so suggestions for how to implement this is most welcome.
Your patch is completely correct in that an attribute on a mixin should take
precedence that of super-class mixins.The story is a little different for
attributes on mapped classes, but that's not an issue here. The patch leaves
existing tests unaffected, and is committed in r67a7868cfba1 along with a new
test...thanks !
Sample code:
import unittest
from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, String, Integer, Boolean
Base = declarative_base()
class AbstractA(object):
AttrA = Column(String(50))
def __init__(self, AttrA=AttrA):
self.AttrA = AttrA
class AbstractB(AbstractA):
AttrA = Column(String(50), primary_key=True)
def __init__(self, AttrA, **kwargs):
AbstractA.__init__(self, **kwargs)
self.AttrA = AttrA
class Concrete(Base, AbstractB):
__tablename__ = 'Concrete'
AttrB = Column(Boolean)
def __init__(self, AttrB, **kwargs):
AbstractB.__init__(self, **kwargs)
self.AttrB = AttrB
class TestAttributeOverriding(unittest.TestCase):
def testAttributeOverriding(self):
concrete = Concrete(AttrB = False, AttrA=0)
self.session.add(concrete)
self.session.commit()
assert len(self.session.query(Concrete).all()) == 1
def setUp(self):
self.engine = create_engine('sqlite:///:memory:', echo = True)
Session = sessionmaker(bind = self.engine)
self.session = Session()
self.metadata = Base.metadata
self.metadata.create_all(self.engine)
def tearDown(self):
self.metadata.drop_all(self.engine)
self.session.close()
This would fail with could not assemble any primary key columns for
mapped
table unless i apply the small patch below, which makes it work as i
would
expect (although i don't know if this is how it is intended to be):
--- /usr/lib/python2.6/site-packages/sqlalchemy/ext/
declarative.py
2010-09-07 19:05:34.0 +0200
+++ lib/python2.6/site-packages/SQLAlchemy-0.6.4-
py2.6.egg/sqlalchemy/ext/declarative.py2010-10-21
19:58:15.863671633
+0200
@@ -936,11 +936,13 @@
'__table__' in dict_ and
name in dict_['__table__'].c
):
-potential_columns[name] = \
-column_copies[obj] = \
-obj.copy()
-column_copies[obj]._creation_order = \
-obj._creation_order
+if name not in potential_columns:
+potential_columns[name] = \
+column_copies[obj] = \
+obj.copy()
+column_copies[obj]._creation_order =
\
+obj._creation_order
+
elif isinstance(obj, MapperProperty):
raise exceptions.InvalidRequestError(
Mapper properties (i.e. deferred,
---
Oystein
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Re: [sqlalchemy] Is it safe to use ORM alongside with the use of mysql queries?
there's no problem at all. If you are working with the ORM and SQL in one transaction, you might need to expire your objects to get a hold of the changes you issue via SQL, until you commit() the transaction which expires everything (or start a new session). On Oct 20, 2010, at 3:16 PM, palmprefan wrote: Hi, I am a sqlalchemy newbie and wonder if it is safe to do this in my code (for read only): conn = connection.engine.connect() conn.execute(select[t1.amount]) while at the same time in another thread querying/updating t1 via an object mapped to the table. Please let me know if this would cause potential problems. Thanks in advance. -- 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. -- 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.
Re: [sqlalchemy] How to update TableRelations
On Oct 20, 2010, at 3:38 AM, Aydın ŞEN wrote:
I defined my tables below as declarative
class MyTable(Base):
__tablename__ = 'mytable'
id = Column(Integer,primary_key = True)
title = Column(String(200))
description = Column(String(200))
dt_st = Column(Date, default=func.current_date())
dt_fn = Column(Date, default=func.current_date())
content = Column(Unicode)
bla bla bla
I have a dictionary post data which includes update values, let it be:
myDict = {title: newTitle, content: newContent}
myDict values are arbitrary so i want to update MyTable with only keys and
values in myDict (not write one by one table fields). What is the elegant way
to do this?
query has an update():
query(MyTable).filter(MyTable.id==5).update(myDict)
otherwise:
for k in myDict:
setattr(some_object, k, myDict[k])
Session.commit()
My second question is about relation, lets add this relation definition to my
table definition:
categories = relation(Category, order_by=Category.id,
backref=MyTable)
class Category(Base):
__tablename__ = 'category'
id = Column(Integer, primary_key = True)
title = Column(String(200))
description = Column(String(200))
How can i update categories when i update MyTable?
same techniques, update myDict with {'categories':[x, y, z]}
--
Aydın Şen
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Re: [sqlalchemy] dynamic load better choice than joinedload?
On Oct 20, 2010, at 5:54 PM, Alvaro Reinoso wrote: Hello, I'd like to know what the best choice is. This is what I do in my system: I'm using grok server and python on the server side; and javascript on the client side. I store all the user data in a session object and this data gets called twice, one to render the HTML on the server side and another to send the data to the client side because the client side is dynamic. I'm using joinedload right know but I know I can't use operations such as, append and remove, when the user update or add something. there's no restriction on collection mutation when different loaders are called. The collection has append(), remove(), extend(), __setitem__(), etc. The timeout of the session object is one hour. I'd like to know if it's better to use dynamic load because I guess with dynamic load you have an open connection to the database, so it might take many resources. The user object might contain a big collections of data. use dynamic loaders if you want to load only particular slices of the collection, instead of the whole thing at once, into memory. If you can afford to have the whole collection in memory, then the usual loaders are better. -- 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.
Re: [sqlalchemy] Result of a table.update()
an UPDATE statement returns no rows unless RETURNING was used to return columns from those rows that were updated. When an UPDATE or DELETE is emitted, result.rowcount contains the number of rows that were matched by the statement's criterion. On Oct 21, 2010, at 2:06 AM, Warwick Prince wrote: Hi All I'm using 0.6.4 under Windoze with MySQL, Python 2.6.4 and I had code that I thought worked before (0.6.3) - which appeared to break due to this issue.. I could be wrong on this point so I'll just get to the crux of the matter... I have a result = table.update(whereClause, values=someValuesDict).execute() The table is updated correctly, however, the resultproxy object I receive as 'result' appears to have no members. If I fetchone() or fetchall() I simply get a None result. Is this correct? If this IS correct, how is the best way to tell if the update was a success? I tried putting bad data in the whereClause and it simply did nothing to the database, but my resultproxy was the same. No Exceptions raised in either case? Please enlighten me.. Cheers Warwick Warwick Prince Managing Director mobile: +61 411 026 992 skype: warwickprince phone: +61 7 3102 3730 fax: +61 7 3319 6734 web: www.mushroomsys.com -- 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. -- 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.
Re: [sqlalchemy] Result of a table.update()
HI Michael Thanks for the info. .rowcount was the missing link I needed. I'll also play with RETURNING as well as I thought I had tried that at one stage and saw no change in the SQL emitted, so moved on. I'll let you know. Cheers Warwick an UPDATE statement returns no rows unless RETURNING was used to return columns from those rows that were updated. When an UPDATE or DELETE is emitted, result.rowcount contains the number of rows that were matched by the statement's criterion. On Oct 21, 2010, at 2:06 AM, Warwick Prince wrote: Hi All I'm using 0.6.4 under Windoze with MySQL, Python 2.6.4 and I had code that I thought worked before (0.6.3) - which appeared to break due to this issue.. I could be wrong on this point so I'll just get to the crux of the matter... I have a result = table.update(whereClause, values=someValuesDict).execute() The table is updated correctly, however, the resultproxy object I receive as 'result' appears to have no members. If I fetchone() or fetchall() I simply get a None result. Is this correct? If this IS correct, how is the best way to tell if the update was a success? I tried putting bad data in the whereClause and it simply did nothing to the database, but my resultproxy was the same. No Exceptions raised in either case? Please enlighten me.. Cheers Warwick Warwick Prince Managing Director mobile: +61 411 026 992 skype: warwickprince phone: +61 7 3102 3730 fax: +61 7 3319 6734 web: www.mushroomsys.com -- 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. -- 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. -- 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.
Re: [sqlalchemy] Attribute overriding in mixin inheritance hierarchy
On Thursday 21. October 2010 22.58.35 Michael Bayer wrote: On Oct 21, 2010, at 2:39 PM, oystein wrote: Hi all, I am using declarative to model an existing object hierarchy where there is an abstract part that i model as an hierarchy of mixins and a concrete part where i use joined-table inheritance. I have a problem when there is attributes with the same name, one overriding the other, in the abstract mixin hierarchy. Maybe I am doing something wrong so suggestions for how to implement this is most welcome. Your patch is completely correct in that an attribute on a mixin should take precedence that of super-class mixins.The story is a little different for attributes on mapped classes, but that's not an issue here. The patch leaves existing tests unaffected, and is committed in r67a7868cfba1 along with a new test...thanks ! Thanks for the quick response and the work you put into sqlalchemy! Its impressive to see how you keep up with all the questions on the mailinglist. --- Oystein -- 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.
