[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
Thanks for the help. I almost have this up and running, but I have found one preplexing issue. My current code base has a very extensive test suite. As part of this test suite, I have my test fixtures setup and teardown databases, mappers, and just about every SA related. This is meant to help keep each test clean from anything remaining from the previous test. As part of the setup and teardown for the tests, I explicitly call sa.orm.clear_mappers() to clear out all mappers that were setup in the previous tests. This was not a problem before the declarative code change-over because each time I setup the DB's for the tests I have the system call an initialization method that sets up all metadata, mappers, etc. But now, with the mappers being created behind the scenes I don't have any way to force the system to recreate the metadata or mappers. Is there some way to clear the declarative layer and have it regenerate all automatically created metadata and mappers? -Allen On Mon, Apr 28, 2008 at 5:07 PM, Michael Bayer [EMAIL PROTECTED] wrote: On Apr 28, 2008, at 5:42 PM, Allen Bierbaum wrote: So, if I understand this right, I could import a base module that does a lazy creation of the Base class with a metadata object and then just use that base class everywhere I need it for the declarative class definitions. Then at a later time (before I use the mapped classes), I could go and bind the metadata for the Base class to an engine for use. Correct? (I apologize if I used the terms incorrectly). If this is true, then I think I see how I can solve my problem. thats right. the whole idea of declarative_base is that its just a common base class from which all your other classes inherit. then you can plug whatever engine configuration is needed at any point in time and it will become active for all base-inheriting classes. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
On May 5, 2008, at 5:04 PM, Allen Bierbaum wrote: Is there some way to clear the declarative layer and have it regenerate all automatically created metadata and mappers? not as of yet but this could be done. but if you are using declarative, that implies that for a class X there is only one mapping. what's the need to call clear_mappers() ? are there other, non-declarative mappers which are interacting with the declarative ones and require changes on each test ? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
On Mon, May 5, 2008 at 4:29 PM, Michael Bayer [EMAIL PROTECTED] wrote: On May 5, 2008, at 5:04 PM, Allen Bierbaum wrote: Is there some way to clear the declarative layer and have it regenerate all automatically created metadata and mappers? not as of yet but this could be done. but if you are using declarative, that implies that for a class X there is only one mapping. what's the need to call clear_mappers() ? are there other, non-declarative mappers which are interacting with the declarative ones and require changes on each test ? Not really. I was just trying to be very cautious and isolate each unit being tested. If that is not possible right now, that is fine. I can still get the test suite up and running, I just have to change the code that was trying to isolate each db test. Thanks, Allen --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
So, if I understand this right, I could import a base module that does a lazy creation of the Base class with a metadata object and then just use that base class everywhere I need it for the declarative class definitions. Then at a later time (before I use the mapped classes), I could go and bind the metadata for the Base class to an engine for use. Correct? (I apologize if I used the terms incorrectly). If this is true, then I think I see how I can solve my problem. -Allen On Sun, Apr 27, 2008 at 6:28 PM, Michael Bayer [EMAIL PROTECTED] wrote: On Apr 27, 2008, at 8:25 AM, Allen Bierbaum wrote: The problem that as I understand it, to use declarative, you can't import an module that defines a table-based object until after some initialization code has been run to connect to a database and create a 'Base' class for the declarative layer. This is not true; the declarative extension serves as a holding zone for a MetaData object; like the MetaData object, it requires no association to any database engine at any time. The initial example in the declarative docunentation, which I am going to change right now, illustrates the engine being associated with the underlying MetaData as just as an example.The only time a databse connection is needed is when you are ready to query the database. You can create your Session and bind it to a newly created engine right before the first query is issued, if you like. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
On Apr 28, 2008, at 5:42 PM, Allen Bierbaum wrote: So, if I understand this right, I could import a base module that does a lazy creation of the Base class with a metadata object and then just use that base class everywhere I need it for the declarative class definitions. Then at a later time (before I use the mapped classes), I could go and bind the metadata for the Base class to an engine for use. Correct? (I apologize if I used the terms incorrectly). If this is true, then I think I see how I can solve my problem. thats right. the whole idea of declarative_base is that its just a common base class from which all your other classes inherit. then you can plug whatever engine configuration is needed at any point in time and it will become active for all base-inheriting classes. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Using declarative when imports happen before create_engine() ??
On Apr 27, 2008, at 8:25 AM, Allen Bierbaum wrote: The problem that as I understand it, to use declarative, you can't import an module that defines a table-based object until after some initialization code has been run to connect to a database and create a 'Base' class for the declarative layer. This is not true; the declarative extension serves as a holding zone for a MetaData object; like the MetaData object, it requires no association to any database engine at any time. The initial example in the declarative docunentation, which I am going to change right now, illustrates the engine being associated with the underlying MetaData as just as an example.The only time a databse connection is needed is when you are ready to query the database. You can create your Session and bind it to a newly created engine right before the first query is issued, if you like. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
