在主数据库中插入记录;从另一个表中插入外键列

Question

EDIT: It's seemingly the term 'bridging tables' got what I need

I'm trying to insert a record in a table produ_tag with a primary and foreign key as columns.

produ_tag

products

tags

The first column refHe is the code of the product from products table, the second contains the tag for the product from tags table. The modeling software made this additional table so it can saves which product contains which tag which is necessary.

The problem is they're primary, so if I have a product with 2 tags, the record won't be inserted, as it has already the same product inserted previously.

Should I delete the primary thing for both? Or there is another way to handle this, as the modeling software rendered it that way.

Answer 1

The produ_tag table is a "bridging table", and the the composite primary key will allow any number of tags (namCh) to be associated with a product (refHe), provided that the tag exists in the tags table and that the (refHe, nameCh) pair is unique (i.e. you can't associate the same product and tag more than once).

If you get an error trying to insert a tag, it's not due to a faulty PK setup. You're either trying to reference a tag that doesn't exist, or you're inserting a combination of values that are already present in the table.

Don't delete your primary keys. The only obvious problem I see is that there's no FK constraint from produ_tag.refHe to products.refHe.