Forum OpenACS Development: To associate 2 content_types

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Posted by Iuri Sampaio on
Hi there,

I need to create a relationship between pa_album and a custom content_type (i.e. ee_venue).

What'd be the best way to relate those content_types, through their items or objects?

I notice there's a ad_proc called content::item::relate, but its arguments item_id and object_id made me think twice if that ad_proc was intended to relate cr_items, but cr_items and acs_objects only.

/api-doc/proc-view?proc=content%3a%3aitem%3a%3arelate&source_p=1

Best wishes,

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Posted by Antonio Pisano on
Hello Iuri

There is quite some machinery in the content repository to relate stuff to content items, but might be overkill in many cases.

A very generic, no rocket-science way to relate arbitrary acs-objects is the attachments package[1]. It is basically a two columns table referencing acs_objects (with proper on delete cascade defined in case one of the two objects gets deleted).

Hope this helps

[1] https://openacs.org/api-doc/package-view?version_id=5374040&public_p=1&about_package_key=&kind=procs

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Posted by Iuri Sampaio on
Antonio,

I was expecting to create a relation such as: using acs_rels to create role and type, as in this sample with videos and thumbs :
select acs_rel_type__create_role(
'video_object', --role
'Video', --pretty_name
'Videos' --pretty_plural
);

select acs_rel_type__create_type(
'video_image_thumbnail_rel', --rel_type
'#acs-subsite.Video_Image_Thumbnail#', --pretty_name
'#acs-subsite.Video_Image_Thumbnails#', --pretty_plural
'relationship', --supertype
'video_image_thumbnail', --table_name
'image_id', --id_column
'video_image_thumbnail_rel', --package_name
'content_item', --object_type_one
'video_object', --role_one
1, --min_n_rels_one
1, --max_n_rels_one
'content_item', --object_type_two
null, --role_two
0, --min_n_rels_two
1 --max_n_rels_two
);

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Posted by Iuri Sampaio on
Hi there,

As one of other solutions, I've written the following chunks to acs_rels data model, plus I’ve added a few other glue codes along with item-add.tcl , photos-add and so on. All them within a new and customized page and package.

Is there any documentation/tutorial about how to use cr_items and revisions within custom packages?

I found none at:
1. https://openacs.org/storage/download/OpenACS_Tutorial.htm?file_id=2938446
2. https://openacs.org/doc/acs-package-dev

Example:
From item_id to album_id
set album_id [relation::get_object_two -object_id_one $item_id -rel_type "ee_item_album_rel"]

and vice-versa
set item_id [relation::get_object_one -object_id_two $album_id -rel_type "ee_item_album_rel"]

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Posted by Iuri Sampaio on
I guess I got it!
https://openacs.org/doc/acs-content-repository/

I wonder if there's a tutorial as in:
HOW TO USE OBJECTS? :
https://openacs.org/storage/download/OpenACS_Tutorial.htm?file_id=2938446#_Toc229651001

Best wishes,

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Posted by Iuri Sampaio on
A suggestion:
we could add this thread as a new topic within the documentation
of https://openacs.org/doc/acs-content-repository/

There's an item already, called as: Relating content to other objects.

This thread could be:
Relating content to other content items
https://openacs.org/doc/acs-content-repository/

Best wishes,

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Posted by Dave Bauer on
If you control at least one of the objects/packages code you can always add a foreign key or a simply mapping table for many to many or one to many relations.

You can use acs_data_links for simple relationships also.

See acs-tcl/tcl/application-data-links-procs.tcl

Much simpler. If you are adding code to acs_rels you probably are making it more difficult than it needs to be.

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Posted by Iuri Sampaio on
Right on! The ad_proc /api-doc/proc-view?proc=application_data_link%3a%3anew&source_p=1

is the one.

Thanks again Dave!