Our Primary Key and Foreign key constraints always have allowed creaing and ensuring '1 to many' table relationships. After researching, there is no direct way to implement such a case with Informix. The only safe way is to create a primary key on the 'parent' table, a unique index on the 'child' table plus a trigger with references that will catch insert and delete. This trigger will fire a SPL that will count the rows in the parent table matching the new key. If 1 row, the child row is created, else the SP returns an error. Same principle for DELETE
Why is it useful?
|Who would benefit from this IDEA?||Anyone who needs to implement a one to one relationship in a safe, generic and simple way|
How should it work?
MS SQL Server has this feature, which is pretty well described in this URL https://www.tech-recipes.com/rx/56738/one-to-one-one-to-many-table-relationships-in-sql-server/
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