我有3个表,定义为3个案例类。卖方和买方都与地址有一对多的关系。有没有办法我可以使用地址表中的一个外键指向卖方和买方表,而不是使用两个外键?我不知道如何编写映射。这是我得到的:
case class Seller(id: Long, name: String)
case class Buyer(id: Long, name: String)
case class Address(id: Long, street: String, city: String, userId: Long)
class SellerTableDef(tag: Tag) extends Table[Seller](tag, "seller") {
def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
def name = column[String]("name")
override def * = (id, name) <> (Seller.tupled, Seller.unapply)
}
class BuyerTableDef(tag: Tag) extends Table[Seller](tag, "buyer") {
def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
def name = column[String]("name")
override def * = (id, name) <> (Buyer.tupled, Buyer.unapply)
}
class AddressTableDef(tag: Tag) extends Table[Address](tag, "address") {
def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
def street = column[String]("street")
def city = column[String]("city")
def userId = column[Long]("user_id")
//!!!Can I use one foreign key to point to both the Seller and the Buyer table?!!!
def user = foreignKey("user_FK", userId, ???)(_.id)
}
非常感谢。
这似乎更像是一个DB设计问题。
通常的做法是拥有买方表,卖方表,地址表。然后每个买方/卖方行都有一个地址ID FK。地址表不应具有买方/卖方ID,因为该地址可能属于多行
评论后编辑:
在这种情况下,您需要一个BuyerAddress(与SellerAddress相同)表,其中包含buyerId和addressId,它将保留每个买方的所有地址(buyerId,addressId)
BuyerTable:id,name SellerTable:id,name AddressTable:id,street,city,userId BuyerAddressTable:buyerId,addressId SellerAddressTable:sellerId,addressId