Fundamentally the cascade applies to doing something to the 'many' side
when something happens on the 'one' side.
A many-to-many association can't do this sort of things, and in fact,
you can't just 'create' a many-to-many relationship in a relational
database. To implement a many-to-many relationship, you need an
intermediary table that is many-to-one with each of the two sides to
build that many-to-many relationship.
You could use a cascade to update this interconnection table, to delete
the cross connection terms when you delete one side of a relationship
(and if you don't you can't delete the items without first removing all
the relationships). By itself, this doesn't help you, but you could
create a trigger on deleting this crossing element, and have it check if
after it is gone if the secret it was connected to is now no longer
referenced, and if so delete the secret.
On 11/2/21 4:49 PM, Anders Buch wrote:
Hello All,
Suppose I have a table of people, a table of secrets, and a
many-to-many association table between them. A person can exist
without knowing any secrets, but a secret without any associated
people might as well be deleted. My reading of the documentation is
that it is not possible to set cascade options to obtain this
behavior? (Because a cascade delete option would cause a secret to be
deleted if any person forgets about it?) If correct, is there another
elegant way to achieve this?
Thanks in advance!
Anders Buch
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