Question

I have a product table:

ProdId(PK)
Prod1
Prod2
Prod3 
Prod4    

and Certification table:

Certification(PK):
Cert1
Cert2
Cert3

How do I Model the following relation (pseudo table):

ProdwithCertId(PK)              ProdwithCert
ProdwithCert1                   "Prod1 with Cert1"
ProdwithCert2                   "Prod1 with Cert1, Cert2"
ProdwithCert3                   "Prod1 with Cert1, Cert2, Cert3"
ProdwithCert4                   "Prod2 with Cert1, Cert2"
ProdwithCert5                   "Prod2 with Cert1, Cert2, Cert3"

Cannot have duplicates, e.g. in above table, ProdwithCert6 - "Prod2 with Cert1, Cert2, Cert3" is not allowed

Answer 1

This is the schema.

table product (id, name)
table certification (id, name)
table product_group (id, product_id)
table product_group_certification (id, product_group_id, certification_id)

Now, let’s assume we took the Prod2 in your example above, in this schema it looks like this.

**product**
1, Prod2

**certification**
1, Cert1
2, Cert2
3, Cert3

**product_group**
1, 1  // Prod2 with Cert1, Cert2
2, 1  // Prod2 with Cert1, Cert2, Cert3

**product_group_certification**
1, 1, 1
2, 1, 2
3, 2, 1
4, 2, 2
5, 2, 3