if you have a relationship() with delete-orphan, SQLAlchemy will not let you save the child without the parent being attached. It is more or less a bug in that this particular check is unnecessary, and you should upgrade to 0.7.
On Dec 11, 2011, at 12:00 AM, Hector Blanco wrote: > Thank you for your reply. > > I'm not exactly sure of what is blocking the insert. I would say > SqlAlchemy, because my Foreign Keys are nullable (which raises the > question of whether it's a good design or not... but that's a > different story) > > I read in the documentation: > http://www.sqlalchemy.org/docs/orm/relationships.html > > " if an item of the child’s type is detached from its parent, mark it > for deletion" > > Is there a way of put (or add) the parent "manually" in a child? I > believe that might work, because the parent is going to be merged, > flushed, commited and... written in the database when I start loading > the child > > Again, thank you > > 2011/12/10 Michael Bayer <mike...@zzzcomputing.com>: >> >> On Dec 10, 2011, at 7:07 PM, Hector Blanco wrote: >> >>> >>> >>> That data (is JSON) is sent to the Category "handler". That handler >>> does the following >>> 1) Creates a new Category() instance, >>> 2) Fill the non-relationship fields ("_name" in this case) >>> 3) Adds the category to the session, so it gets an _id >>> 4) Go through the relationships fields ("_products") >>> 5) If there's a dictionary inside, call recursively to the same method >>> with that dictionary. >>> 6) The recursive call will try to create a new product (with the >>> proper "_model") and TRIES to add it to the database >>> 7) The recursive call returns, so that newly created product can be >>> added to the "_products" relationship of the category and the backref >>> will properly set up the "_category" relationship in the product >>> >>> And in the 6th point is where my problem shows up: If I set up the >>> delete-orphans, the database detects that I'm trying to insert a >>> product that doesn't belong to a category, therefore, it's orphan... >>> and blows up. >>> >>> Is there a way to delay the triggering of the "delete-orphans" or... >>> or something similar, so I can have a product not belonging to a >>> category... for a bit (until the category has finished loading?) >> >> when you say "the database detects" it's not entirely clear what you mean; >> SQLA 0.6 and earlier will prevent you from persisting a "delete-orphan" >> without a parent, before it ever goes to the database. So that's SQLA >> preventing the operation, not the DB. OTOH if your foreign key is NOT NULL >> then the DB prevents the orphan row from being INSERTed no matter what SQLA >> allows or not. >> >> So it depends on specifically what is blocking the activity from happening - >> if you want to INSERT rows with a null foreign key and still have >> delete-orphan, you'd need to use SQLAlchemy 0.7 which removes the "orphan" >> detection at the INSERT level. If you don't want to actually have any >> "orphaned" rows in the DB ever and the FK will be NOT NULL, then you have to >> organize your steps such that the INSERTs don't occur until everything is >> ready to go in - that's regardless of SQLAlchemy version. Nothing regarding >> orphans happens in any case until a flush occurs. So if its a simple >> matter of delaying the flush, just turn off autoflush temporarily. >> >> >> >> -- >> 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. >> > > -- > 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. > -- 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.
