@unique
from
PrismaのAttributes
@unique
UNIQUE制約
https://www.prisma.io/docs/concepts/components/prisma-schema/data-model#defining-a-unique-field
複合でのunique指定もできる
code:schema.prisma
model User {
id Int @id
email String
address Address
@@unique(
email, address.number
) ←これ
}