Relationship between three entities
Hi,
I have a real case that requires an associative table with three keys, Elgg provides the relationship table that can not link three objects together.
For example : A Proffesor who teaches at several universities, he was assistant in the school 1 department boss in school 2, it has several functions / roles at the same time in many shools.
Here, we have :
Professor -> Assistant -> School 1
Professor 1 -> Boss -> School 2
The prefix_entity_relationships table must contain :
guid_professor1 -> guid_function1 -> guid_shcool1
guid_professor1 -> guid_function2 -> guid_shcool2
or also have
guid_professor2 -> guid_function1 -> guid_shcool1
contrariwise, if we put :
guid_professor1 -> guid_function1 =>Where the professor 1 occupies the position 1 ? school 1 or shool 2
guid_professor1 -> guid_shcool1 => What position the professor 1 occupies in school 1 ? function 1 or function 2
guid_function1 -> guid_shcool1 => Who professor have the position 1 in school 1 ? professor 1 or an other professor 2
Thank you for your help
- Matt Beckett@Beck24
Matt Beckett - 0 likes
- Riadh Hamdi@riadh.hamdi
Riadh Hamdi - 0 likes
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The answer is to either use different relationship names
Sorry matt, I think to expand the topic.
But the answer does not answer exactly the question. The current model can't implement a relation beetwwen more than two entities, In design,ie an associative table with more primary key has a cardinality of 0 .. n
Thank you