我有一张product
桌子:
ProdId(PK)
Prod1
Prod2
Prod3
Prod4
和Certification
表:
Certification(PK):
Cert1
Cert2
Cert3
如何建模以下关系(伪表):
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"
不能有重复项,例如上表,ProdwithCert6 - "Prod2 with Cert1, Cert2, Cert3"
是不允许的