Linking to objects, or Keeping track of moving objects
I'm creating a Recipe object, which will contain numerous Ingredient objects. Each Ingredient objects has to point or reference a Food object, which is stored elsewhere in the database. So, we can have different Ingredients pointing at the same Food object. The question is, how do I create a reference to the Food object? If I just store the path to the Food object as a string (e.g. a property containing "/Foods/Oil/OliveOil"), if someone moves the Food object my reference will be wrong. Likewise if someone renames the Food object. I could each Food object a unique ID, and have some sort of lookup object that gives the path of an object based on ID, but what happens when someone does a "Copy" & "Paste"? I could store Food objects in an SQL db, but I'd much rather use ZODB so I can use acquisition and to reduce overhead. Any idea on how to do this? -- Itamar - itamars@ibm.net ---------------------------o----------------------------------------------o Perl/Gimp Greeting Cards | Trust? Ha! The US dollar is backed by ICBMs! | http://www.sealingwax.com | --Anonymous Coward, Slashdot |
I'm fairly new to Zope myself, but I think if you give the Food objects unique ID's and you create a ZCatalog that indexes that ID property, you can allways get the path to the Food object (if you keep the ZCatalog up to date), trough ZCatalogs standard methods. ZCatalog is real easy to use for that. I was thinking about that so I could use links based on a unique ID instead of standard hyperlinks. That way I can move objects around wherever I want them and don't have to worry about breaking links. But then it would of course still be possible to Copy and Paste the object with that ID, which in your situation would be undesirable... Best, Leon de Heus. Itamar Shtull-Trauring wrote:
I'm creating a Recipe object, which will contain numerous Ingredient objects. Each Ingredient objects has to point or reference a Food object, which is stored elsewhere in the database.
So, we can have different Ingredients pointing at the same Food object.
The question is, how do I create a reference to the Food object? If I just store the path to the Food object as a string (e.g. a property containing "/Foods/Oil/OliveOil"), if someone moves the Food object my reference will be wrong. Likewise if someone renames the Food object.
I could each Food object a unique ID, and have some sort of lookup object that gives the path of an object based on ID, but what happens when someone does a "Copy" & "Paste"?
I could store Food objects in an SQL db, but I'd much rather use ZODB so I can use acquisition and to reduce overhead.
Any idea on how to do this?
-- Itamar - itamars@ibm.net ---------------------------o----------------------------------------------o Perl/Gimp Greeting Cards | Trust? Ha! The US dollar is backed by ICBMs! | http://www.sealingwax.com | --Anonymous Coward, Slashdot |
_______________________________________________ Zope-Dev maillist - Zope-Dev@zope.org http://www.zope.org/mailman/listinfo/zope-dev
(Related lists - please, no cross posts or HTML encoding!
To receive general Zope announcements, see: http://www.zope.org/mailman/listinfo/zope-announce
For non-developer, user-level issues, zope@zope.org, http://www.zope.org/mailman/listinfo/zope )
Itamar Shtull-Trauring wrote:
I'm creating a Recipe object, which will contain numerous Ingredient objects. Each Ingredient objects has to point or reference a Food object, which is stored elsewhere in the database.
So, we can have different Ingredients pointing at the same Food object.
The question is, how do I create a reference to the Food object? If I just store the path to the Food object as a string (e.g. a property containing "/Foods/Oil/OliveOil"), if someone moves the Food object my reference will be wrong. Likewise if someone renames the Food object.
I could each Food object a unique ID, and have some sort of lookup object that gives the path of an object based on ID, but what happens when someone does a "Copy" & "Paste"?
I could store Food objects in an SQL db, but I'd much rather use ZODB so I can use acquisition and to reduce overhead.
Any idea on how to do this?
This came up back in July, here was my original post: http://www.zope.org:12080/archives/Catalog/archives/1999-July/006332.html Some code was posted that might help: http://www.zope.org:12080/archives/Catalog/archives/1999-July/006340.html And a clarification: http://www.zope.org:12080/archives/Catalog/archives/1999-July/006356.html Eventually, I submitted a feature request to the collector which was downgraded to a wish: http://www.zope.org:8080/Collector/380/view HTH, Michael Bernstein.
participants (3)
-
Itamar Shtull-Trauring -
Leon de Heus -
Michael Bernstein