[sqlalchemy] Re: Come on, share your sqlalchemy powered sites with others.//Fwd: A tornado powered site to show any project powered sites(open source)
It's official online now after two weeks beta testing. A bunch of sites already been submitted, come on and enjoy it. Below list some popular projects' sub-sites: http://sqlalchemy.poweredsites.org SQLAlchemy powered sites. http://ror.poweredsites.org http://ror.poweredsites.org/Ruby on Rails powered sites http://django.poweredsites.org Django powered sites http://mongodb.poweredsites.org MongoDB powered sites. http://jquery.poweredsites.org jQuery powered sites http://python.poweredsites.org Python powered sites http://yii.poweredsites.org Yii framework powered sites. http://flask.poweredsites.org Flask powered sites. On Sun, Aug 8, 2010 at 12:56 PM, Stone Puzzle stonepuz...@gmail.com wrote: SqlAlchemy powered sites list http://sqlalchemy.poweredsites.org -- Forwarded message -- From: Felinx Lee felinx@gmail.com Date: Tue, Aug 3, 2010 at 2:29 PM Subject: A tornado powered site to show any project powered sites(open source) To: python-torn...@googlegroups.com I am very pleased to announce the beta release of http://poweredsites.org(A tornado powered site to show any project powered sites) *What powered sites?* We are always curious about that when we navigating exciting sites. PoweredSites is a good site to share with others about a project or service powered sites, eg. jQuery powered sites http://jquery.poweredsites.org/, Torando powered sites http://tornado.poweredsites.org/. PoweredSites is also a good place to show your project's power if you are a project owner. PoweredSites source code is opened to the community under Apache License V2, the source code is available at http://www.bitbucket.org/felinx/poweredsites, it's develop by python http://www.python.org/and tornado http://www.tornadoweb.org/. I opened everything except the OpenID API key:), so you can setup a web site using the code easily. Currently, twitter,facebook,friendfeed openid login are no well tested because those web sites are blocked in China. And some of features are still under developing, eg. re-edit a project or site and wiki for every project. *I hope that you will enjoy the site and the source code.* *I hope some guys can join me to make the site better.* Please don't hesitate to submit your projectshttp://poweredsites.org/submit/projectpreor submit web sites http://poweredsites.org/submit/sitepre to http://poweredsites.org/. And any bug reports are welcome. For detail information and comments, please visit here. http://blog.poweredsites.org/entry/poweredsites-beta-online BTW: You can submit and find tornado powered sites from http://tornado.poweredsites.org now. Cheers. -- Felinx Lee What powered the sites? http://poweredsites.org What can change the nature of a man?(Planescape Torment) http://en.wikipedia.org/wiki/Planescape:_Torment -- 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] How to declare many-to-one in this example?
I'm new to python(sqlalchemy), and I'm learning to build web site with
pylons and sqlalchemy.
I have a problem when I declare the relationship between models. I've
tried it several hours, but failed. But I think it should be a basic
question.
I have two classes: User and Article, user can create articles, and
modified the other people's article(like wiki).
So a user has created-articles and edited-articles.
class Article(Base):
__tablename__ = 'articles'
id = Column(Integer, primary_key=True)
title = ...
user_id = Column(Integer, ForeignKey('users.id'))
editor_id = Column(Integer, ForeignKey('users.id'))
# relations
user = relationship('User', backref='articles') # - has error
class User(Base):
pass
But there is an error displayed:
InvalidRequestError: One or more mappers failed to compile. Exception
was probably suppressed within a hasattr() call. Message was: Could
not determine join condition between parent/child tables on
relationship Article.user. Specify a 'primaryjoin' expression. If this
is a many-to-many relationship, 'secondaryjoin' is needed as well.
I tried to add `primaryjoin` to the line('has error'), but don't know
what it should be. I tried some codes, but none works.
Thank you in advance!
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Re: [sqlalchemy] Re: Polymorphic across foreign key
On Aug 22, 2010, at 8:45 AM, Eduardo Robles Elvira wrote: On May 15 2008, 6:27 pm, Michael Bayer mike...@zzzcomputing.com wrote: On May 15, 2008, at 12:12 PM, J. Cliff Dyer wrote: How can I use this field for polymorphism? Is it possible? polymorphicdiscriminators are currently table-local scalar columns. So if you had a many-to-one of discriminators, youd currently have to encode the discriminator to the primarykeyidentifier of each discriminotor. We will eventually allow a python function to be used as a discriminator as well which you can use to add a level of abstraction to this (you'd preload the list of discriminiator objects and again map based on primarykey). Hello! Two years later.. :P Are we going to get a python function to be used as a discriminator soon? I would think that it would not be very difficult to implement, right? As shown in my previous emails in the thread Model factory, that would solve my problem. Discriminator functions don't solve your issue. Your table already has a discriminator column, so in that regard, determination of discriminiator, which is all that proposed function would ever do, is already provided by the built in functionality. You're looking to rig a non-SQLAlchemy creational pattern into your objects. The MapperExtension method create_instance() provides this capability. Another option is to just use @reconstructor, and just set self.__class__ = whatever class you want. I agree with other posters that the whole idea is a little hacky and if it were me, I would ensure that all Job subclasses are configured and mapped ahead of time. Failing that, if I truly needed to have module paths in the database (which I wouldn't, since I think encoding language-specific constructs in a relational database is a bad idea), I would either have my app do a SELECT DISTINCT of all those modules at startup, pre-load all the classes and map them, or, I'd have Job load an impl based on that module information and proxy methods to the dynamically loaded object (which is not very different from the @reconstructor approach except for structure). I have the python function already written, but I don't know how to make sqlalchemy call to it. I thought that using a composite field should work, but it doesn't because as you say, it's not a table-local scalar column. If the problem is the proxy_set is not set, maybe I can set the proxy_set var to the composite_field somehow? Regards, Eduardo Robles Elvira. -- 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 do I set the transaction isolation level in SQLAlchemy for PostgreSQL?
On Aug 22, 2010, at 10:44 PM, Mahmoud Abdelkader wrote: Hi Michael, Thanks for responding. Will there be any backward incompatibility issues with a SQLAlchemy upgrade to the tip? We're using SQLAlchemy in a rather large project. Thanks! Mahmoud If your app sticks to traditional SQLAlchemy patterns, the upgrade to 0.6 shouldn't have issues - the biggest one could be that you'd have to upgrade your sqlalchemy-migrate if you're on an older version, and I believe they had an API change. An overview of SQLAlchemy changes from 0.5 - 0.6 is at http://www.sqlalchemy.org/trac/wiki/06Migration . Note that the PoolListener approach will work perfectly fine in 0.5, that's what the isolation_level argument in 0.6 uses in any case. Docs are http://www.sqlalchemy.org/docs/reference/sqlalchemy/interfaces.html?highlight=poollistener#sqlalchemy.interfaces.PoolListener . On Sat, Aug 21, 2010 at 10:51 AM, Michael Bayer mike...@zzzcomputing.com wrote: On Aug 19, 2010, at 6:32 PM, Mahmoud Abdelkader wrote: NOTE: I originally posted this question to stack overflow, http://stackoverflow.com/questions/3518863/how-do-i-set-the-transaction-isolation-level-in-sqlalchemy-for-postgresql , but I haven't received an answer yet. If I find the answer here, I'll send it over to stackoverflow for thoroughness. We're using SQLAlchemy declarative base and I have a method that I want isolate the transaction level for. To explain, there are two processes concurrently writing to the database and I must have them execute their logic in a transaction. The default transaction isolation level is READ COMMITTED, but I need to be able to execute a piece of code using SERIALIZABLE isolation levels. Please use the isolation_level argument to create_engine() (http://www.sqlalchemy.org/docs/reference/dialects/postgresql.html?highlight=isolation_level#transaction-isolation-level) and use the latest tip of SQLAlchemy (http://hg.sqlalchemy.org/sqlalchemy/archive/default.tar.gz) until 0.6.4 is released, as there was a psycopg2-specific bug fixed recently regarding isolation level. The approach you have below does not affect the same connection which is later used for querying - you'd instead use a PoolListener that sets up set_isolation_level on all connections as they are created. from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT from psycopg2.extensions import ISOLATION_LEVEL_READ_COMMITTED from psycopg2.extensions import ISOLATION_LEVEL_SERIALIZABLE class OurClass(SQLAlchemyBaseModel): @classmethod def set_isolation_level(cls, level=ISOLATION_LEVEL_SERIALIZABLE): cls.get_engine().connect().connection.set_isolation_level(level) @classmethod def find_or_create(cls, **kwargs): try: return cls.query().filter_by(**kwargs).one() except NoResultFound: x = cls(**kwargs) x.save() return x I am doing this to invoke this using a transaction isolation level, but it's not doing what I expect. The isolation level still is READ COMMITTED from what I see in the postgres logs. Can someone help identify what I'm doing anythign wrong? I'm using SQLAlchemy 0.5.5 class Foo(OurClass): def insert_this(self, kwarg1=value1): # I am trying to set the isolation level to SERIALIZABLE try: self.set_isolation_level() with Session.begin(): self.find_or_create(kwarg1=value1) except Exception: # if any exception is thrown... print I caught an expection. print sys.exc_info() finally: # Make the isolation level back to READ COMMITTED self.set_isolation_level(ISOLATION_LEVEL_READ_COMMITTED) Appreciate the assistance! Thanks Mahmoud -- 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. -- You received this message because you are
[sqlalchemy] DB tables, check exists before creation? duplicate and rename table in sqlalchemy?
Dear All, I have questions in coding my application using sqlalchemy on database tables. 1. how to create table if not exists in metadata.create_all(engine) I googled and fould this http://www.mail-archive.com/sqlalchemy-us...@lists.sourceforge.net/msg02121.html; but I found no keywords matched checkexists=True in the document for version 0.6.4 2. how to duplicate a table with name in sqlalchemy? I posted a question in http://stackoverflow.com/questions/3545140/sqlalchemy-duplicate-table-rename-table; but seems still no answer. 3. how to rename a table in sqlalchemy? Thanks for any hints and answer. Yours, KC -- 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] DB tables, check exists before creation? duplicate and rename table in sqlalchemy?
On Tue, Aug 24, 2010 at 2:04 AM, keekychen.shared keekychen.sha...@gmail.com wrote: Dear All, I have questions in coding my application using sqlalchemy on database tables. 1. how to create table if not exists in metadata.create_all(engine) I googled and fould this http://www.mail-archive.com/sqlalchemy-us...@lists.sourceforge.net/msg02121.html but I found no keywords matched checkexists=True in the document for version 0.6.4 create_all() does this by default. -- With best regards, Daniel Kluev -- 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 declare many-to-one in this example?
On Aug 23, 2010, at 5:37 AM, Freewind wrote:
I'm new to python(sqlalchemy), and I'm learning to build web site with
pylons and sqlalchemy.
I have a problem when I declare the relationship between models. I've
tried it several hours, but failed. But I think it should be a basic
question.
I have two classes: User and Article, user can create articles, and
modified the other people's article(like wiki).
So a user has created-articles and edited-articles.
class Article(Base):
__tablename__ = 'articles'
id = Column(Integer, primary_key=True)
title = ...
user_id = Column(Integer, ForeignKey('users.id'))
editor_id = Column(Integer, ForeignKey('users.id'))
# relations
user = relationship('User', backref='articles') # - has error
class User(Base):
pass
But there is an error displayed:
InvalidRequestError: One or more mappers failed to compile. Exception
was probably suppressed within a hasattr() call. Message was: Could
not determine join condition between parent/child tables on
relationship Article.user. Specify a 'primaryjoin' expression. If this
is a many-to-many relationship, 'secondaryjoin' is needed as well.
I tried to add `primaryjoin` to the line('has error'), but don't know
what it should be. I tried some codes, but none works.
you want to say this:
class Article(Base):
__tablename__ = 'articles'
id = Column(Integer, primary_key=True)
user_id = Column(Integer, ForeignKey('users.id'))
editor_id = Column(Integer, ForeignKey('users.id'))
user = relationship('User', backref='articles',
primaryjoin=Article.user_id==User.id)
class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
this to resolve the ambiguity of how Article would join to User, given that
there are two different foreign keys that reference the 'users' table.
Background documentation is at:
http://www.sqlalchemy.org/docs/mappers.html?highlight=primaryjoin#specifying-alternate-join-conditions-to-relationship
the quoting is specific to declarative:
http://www.sqlalchemy.org/docs/reference/ext/declarative.html?highlight=primaryjoin#configuring-relationships
Thank you in advance!
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Re: [sqlalchemy] DB tables, check exists before creation? duplicate and rename table in sqlalchemy?
On Aug 23, 2010, at 11:04 AM, keekychen.shared wrote:
Dear All,
I have questions in coding my application using sqlalchemy on database
tables.
2. how to duplicate a table with name in sqlalchemy?
I posted a question in
http://stackoverflow.com/questions/3545140/sqlalchemy-duplicate-table-rename-table;
but seems still no answer.
method 1 - produce your Table object with a callable:
def new_table(name, metadata):
return Table(name, metadata,
Column('id',Integer,primary_key=True),
Column('name',String),
Column('fullname',String),
Column('password',String)
)
users = new_table('users', metadata)
users001 = new_table('users_001', metadata)
method 2 - adapt the source code from the tometadata() method of Table, which
copies a Table to a new MetaData. This makes use of the copy() method of
Column and Constraint.
def copy_my_table(name, table):
args = []
for c in table.columns:
args.append(c.copy())
for c in table.constraints:
args.append(c.copy())
return Table(name, table.metadata, *args)
3. how to rename a table in sqlalchemy?
you must issue the appropriate ALTER statements to your database to change the
name of the table. As far as the Table metadata itself, you can attempt to
set table.name = 'newname', and re-place the Table object within
metadata.tables with its new name, but this may have lingering side effects
regarding foreign keys that reference the old name. In general, the pattern is
not supported - its intended that a SQLAlchemy application runs with a fixed
database structure (only new tables can be added on the fly).
You can also check out the Migrate project which allows migrations, but only in
the context of a migration script, not a running application.
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[sqlalchemy] rollbacks on select
Hello, I use the default options to run queries via sql expressions and I've noticed that SQLAlchemy does a rollback after every select using the mysql default engine. These rollback are not really useful and eat 15% of the CPU time. Is this a normal behavior, part of the auto commit custom strategy SQLAlchemy implements ? If yes, is there a way to avoid those extra rollbacks ? Regards Tarek -- Tarek Ziadé | http://ziade.org -- 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] rollbacks on select
Sent from my iPhone On Aug 23, 2010, at 8:29 PM, Tarek Ziadé ziade.ta...@gmail.com wrote: Hello, I use the default options to run queries via sql expressions and I've noticed that SQLAlchemy does a rollback after every select using the mysql default engine. These rollback are not really useful and eat 15% of the CPU time. Is this a normal behavior, part of the auto commit custom strategy SQLAlchemy implements ? If yes, is there a way to avoid those extra rollbacks ? Because we're using a connection pool, putting the connection back into the pool without a rollback means you throw existing transactional locks and state into the pool as well, holding them open indefinitely and generally causing problems for subsequent usages of those pooled connections. However, we get a complaint about every 6 months from a mysql myisam user, who uses many ad-hoc connection checkouts (which in itself is a little unusual) and who would rather not have it (as myisam has no transactional integrity anyway). For those cases, we tell them to add rollback_on_return=False to their create_engine to turn the behavior off. But also maybe consider why you have a high volume of checkins, rather then working in some kind of transaction-per-logical-operation scheme (like a web request). Regards Tarek -- Tarek Ziadé | http://ziade.org -- 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] rollbacks on select
On Mon, Aug 23, 2010 at 5:48 PM, Michael Bayer mike...@zzzcomputing.com wrote: Sent from my iPhone On Aug 23, 2010, at 8:29 PM, Tarek Ziadé ziade.ta...@gmail.com wrote: Hello, I use the default options to run queries via sql expressions and I've noticed that SQLAlchemy does a rollback after every select using the mysql default engine. These rollback are not really useful and eat 15% of the CPU time. Is this a normal behavior, part of the auto commit custom strategy SQLAlchemy implements ? If yes, is there a way to avoid those extra rollbacks ? Because we're using a connection pool, putting the connection back into the pool without a rollback means you throw existing transactional locks and state into the pool as well, holding them open indefinitely and generally causing problems for subsequent usages of those pooled connections. However, we get a complaint about every 6 months from a mysql myisam user, who uses many ad-hoc connection checkouts (which in itself is a little unusual) and who would rather not have it (as myisam has no transactional integrity anyway). For those cases, we tell them to add rollback_on_return=False to their create_engine to turn the behavior off. But also maybe consider why you have a high volume of checkins, rather then working in some kind of transaction-per-logical-operation scheme (like a web request). Thanks Michael ! -- Tarek Ziadé | http://ziade.org -- 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] rollbacks on select
On Mon, Aug 23, 2010 at 5:53 PM, Tarek Ziadé ziade.ta...@gmail.com wrote: On Mon, Aug 23, 2010 at 5:48 PM, Michael Bayer mike...@zzzcomputing.com wrote: Sent from my iPhone On Aug 23, 2010, at 8:29 PM, Tarek Ziadé ziade.ta...@gmail.com wrote: Hello, I use the default options to run queries via sql expressions and I've noticed that SQLAlchemy does a rollback after every select using the mysql default engine. These rollback are not really useful and eat 15% of the CPU time. Is this a normal behavior, part of the auto commit custom strategy SQLAlchemy implements ? If yes, is there a way to avoid those extra rollbacks ? Because we're using a connection pool, putting the connection back into the pool without a rollback means you throw existing transactional locks and state into the pool as well, holding them open indefinitely and generally causing problems for subsequent usages of those pooled connections. However, we get a complaint about every 6 months from a mysql myisam user, who uses many ad-hoc connection checkouts (which in itself is a little unusual) and who would rather not have it (as myisam has no transactional integrity anyway). For those cases, we tell them to add rollback_on_return=False to their create_engine to turn the behavior off. But also maybe consider why you have a high volume of checkins, rather then working in some kind of transaction-per-logical-operation scheme (like a web request). Thanks Michael ! Just for the record for others, the option is reset_on_return Cheers Tarek -- 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.
