Hello *, (Using SQLAlchemy 0.6.8, but planning to move to 0.7 soon)
I am trying to build queries dynamically and I have to add joins on the primary table to be able to create my where-clauses. To add the join clause on my instance of Select, I found this discussion: http://thread.gmane.org/gmane.comp.python.sqlalchemy.user/5910/focus=5917 Now I need to retain the original Select untouched (as it can be used to derive other Select instances). I found out that all the interesting methods on Select deliver a new copy using the @_generative decorator. For append_from, there does not seem to be a generative equivalent. Therefore I want to roll it manually, but I don't really want to call the private _generate method. Therefore I am wondering if there is a canonical way to copy an instance of Select. It seems that pickling is supported (__getstate__ and __setstate__ are provided). However, the class 'sqlalchemy.sql.expression._SelectBaseMixin overrides _generate to "to also clear out exported collections". However, the __getstate__ implementation comes from ClauseElement. My question: Is it supported to do from copy import copy new_select = copy(old_select) where old_select is an instance of Select? Are there any plans to add a generative way to extend the froms of a Select? ;-) Thanks and Greetings, Torsten -- DYNAmore Gesellschaft fuer Ingenieurdienstleistungen mbH Torsten Landschoff Office Dresden Tel: +49-(0)351-4519587 Fax: +49-(0)351-4519561 mailto:[email protected] http://www.dynamore.de Registration court: Mannheim, HRB: 109659, based in Karlsruhe, Managing director: Prof. Dr. K. Schweizerhof, Dipl.-Math. U. Franz -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to [email protected]. 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.
