Re: [ZODB-Dev] Proposal (version 2): cross database reference seat belt
Hi, On Tue, 2009-04-28 at 13:54 -0400, Jim Fulton wrote: Thanks again! (Note to everyone else, Shane and I discussed this on IRC, along with another alternative that I'll mention below.) I like version 2 better than version 1. I'd be inclined to simplify and it and skip the configuration flag and simply publish an event any time we see a cross-database reference when saving an object. Here's proposed solution 3. :) - We add a flag to disable new cross-database references unless they are explicitly registered. - We add a connection method to register a reference: def registerCrossDatabaseReference(from_, to): Register a new cross-database reference from from_ to to. - We arrange that connections can recognize old cross-database references. If someone accidentally creates a new reference and the flag is set, then transaction will be aborted. An interim step, if we're in a hurry to get 3.9 out, is to simply add the flag. This would disallow cross-database references in new applications. These applications could still support multiple databases by providing application-level traversal across databases. I think I'm reading something incorrectly: is there an emphasis on *new* applications? The flag would disallow the creation of cross-database references for a given DB -- independent of whether the app is new or old, right? Only depending on whether the application uses a ZODB that has the feature and has it enabled. Right? Otherwise, I'm +1. Christian -- Christian Theune · c...@gocept.com gocept gmbh co. kg · forsterstraße 29 · 06112 halle (saale) · germany http://gocept.com · tel +49 345 1229889 7 · fax +49 345 1229889 1 Zope and Plone consulting and development signature.asc Description: This is a digitally signed message part ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Proposal (version 2): cross database reference seat belt
Christian Theune wrote: Hi, On Tue, 2009-04-28 at 13:54 -0400, Jim Fulton wrote: Thanks again! (Note to everyone else, Shane and I discussed this on IRC, along with another alternative that I'll mention below.) I like version 2 better than version 1. I'd be inclined to simplify and it and skip the configuration flag and simply publish an event any time we see a cross-database reference when saving an object. Here's proposed solution 3. :) - We add a flag to disable new cross-database references unless they are explicitly registered. - We add a connection method to register a reference: def registerCrossDatabaseReference(from_, to): Register a new cross-database reference from from_ to to. - We arrange that connections can recognize old cross-database references. If someone accidentally creates a new reference and the flag is set, then transaction will be aborted. An interim step, if we're in a hurry to get 3.9 out, is to simply add the flag. This would disallow cross-database references in new applications. These applications could still support multiple databases by providing application-level traversal across databases. I think I'm reading something incorrectly: is there an emphasis on *new* applications? The flag would disallow the creation of cross-database references for a given DB -- independent of whether the app is new or old, right? Only depending on whether the application uses a ZODB that has the feature and has it enabled. Right? I think the emphasis was on new versus existing cross-database references. Laurence ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Proposal (version 2): cross database reference seat belt
On Apr 30, 2009, at 5:01 PM, Christian Theune wrote: Hi, On Tue, 2009-04-28 at 13:54 -0400, Jim Fulton wrote: Thanks again! (Note to everyone else, Shane and I discussed this on IRC, along with another alternative that I'll mention below.) I like version 2 better than version 1. I'd be inclined to simplify and it and skip the configuration flag and simply publish an event any time we see a cross-database reference when saving an object. Here's proposed solution 3. :) - We add a flag to disable new cross-database references unless they are explicitly registered. - We add a connection method to register a reference: def registerCrossDatabaseReference(from_, to): Register a new cross-database reference from from_ to to. - We arrange that connections can recognize old cross-database references. If someone accidentally creates a new reference and the flag is set, then transaction will be aborted. An interim step, if we're in a hurry to get 3.9 out, is to simply add the flag. This would disallow cross-database references in new applications. These applications could still support multiple databases by providing application-level traversal across databases. I think I'm reading something incorrectly: is there an emphasis on *new* applications? No The flag would disallow the creation of cross-database references for a given DB -- independent of whether the app is new or old, right? Right Only depending on whether the application uses a ZODB that has the feature and has it enabled. Right? This is not a sentence. :) The flag would disable implicit references (new or old). When an object is being saved, if it has implicit cross-references, the save will fail. The second and third bullets above provide a way to make explicit references. I've implemented the first bullet. There's a question of whether I need to implement the second 2 bullets for ZODB 3.9. Jim -- Jim Fulton Zope Corporation ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
