[sqlalchemy] Re: Determine what joins are in select statement
Still not there because I am not sure how to compare two join objects. For example let's say I have a join object: obj1 sqlalchemy.orm.util._ORMJoin at 0xac0d30c; Join object on task(172432076) and context(172432940) And I then create a second object: obj2 = sqlalchemy.orm.util.join(Task, Context) obj2 sqlalchemy.orm.util._ORMJoin at 0xae517ac; Join object on task(172432076) and context(172432940) I can't quite figure out how to compare the objects since: obj1.compare(obj2) is False What is the best way to compare those two join objects and conclude they represent the same join? Steve --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Determine what joins are in select statement
On Nov 1, 2009, at 6:27 PM, Steve Zatz wrote: Still not there because I am not sure how to compare two join objects. For example let's say I have a join object: obj1 sqlalchemy.orm.util._ORMJoin at 0xac0d30c; Join object on task (172432076) and context(172432940) And I then create a second object: obj2 = sqlalchemy.orm.util.join(Task, Context) obj2 sqlalchemy.orm.util._ORMJoin at 0xae517ac; Join object on task (172432076) and context(172432940) I can't quite figure out how to compare the objects since: obj1.compare(obj2) is False What is the best way to compare those two join objects and conclude they represent the same join? join() isn't providing a depth-based version of compare() at the moment so compare join.left, join.right, join.onclause. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Determine what joins are in select statement
And what is the approach to the simpler question of determining what joins are in a query. For example, query = session.query(Task).join(Context)... If you're just passed the query, what's the best way to determine that it contains a join (for example, so you don't perform the same join again)? Steve --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Determine what joins are in select statement
Steve Zatz wrote:
And what is the approach to the simpler question of determining what joins
are in a query.
For example,
query = session.query(Task).join(Context)...
If you're just passed the query, what's the best way to determine that it
contains a join (for example, so you don't perform the same join again)?
well I showed the visitor example towards the goal of illustrating a
generalized solution to finding things. just change table to join.
myjoins = set()
visitors.traverse(mystmt, {'join':myjoins.add})
Steve
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[sqlalchemy] Re: Determine what joins are in select statement
just change table to join. I tried that but got an Attribute Error that Query' object has no attribute '__visit_name__' Asume I am doing something wrong by using the query object as the first argument but not sure what to use. Also, what is the second argument in visitors.traverse(). [It was missing in the most recent example but apparently an empty dictionary is fine.] Steve --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Determine what joins are in select statement
Steve Zatz wrote: just change table to join. I tried that but got an Attribute Error that Query' object has no attribute '__visit_name__' Asume I am doing something wrong by using the query object as the first argument but not sure what to use. use query.statement to get at the SQL expression Also, what is the second argument in visitors.traverse(). [It was missing in the most recent example but apparently an empty dictionary is fine.] just an empty dict. it's contents have meaning in some cases but is not generally necessary. it would be preferable if the API didn't stick that boilerplate right in the middle of the function like that but that's sort of how it is for now. Steve --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Determine what joins are in select statement
use query.statement to get at the SQL expression Thanks. That worked. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
