[英]Grails many-to-many relationship across the same table
听起来您只需要一个常规的单向1:
class Employee {
...
static hasMany = [bookmarks: Employee]
}
您可以使用瞬态属性和附加表“书签”来执行此任务:
class Employee {
String name
static transients = ["bookmarks"]
def getBookmarks() {
Bookmark.findAllByBookmarker(this, [sort: "id", order: "asc"])
}
...
}
class Bookmark implements Serializable {
Employee bookmarker // the employee who bookmark someone
Employee bookmarkee // the employee who is bookmarked
static mapping = {
table "Bookmark"
id composite: ['bookmarker', 'bookmarkee']
bookmarker(column: "BOOKMARKER_ID")
bookmarkee(column: "BOOKMARKEE_ID")
version false
}
static Bookmarker get(long bookmarkerId, long bookmarkeeId) {
find 'from Bookmark where bookmarker.id=:bookmarkerId and bookmarkee.id=:bookmarkeeId',
[bookmarkerId: bookmarkerId, bookmarkeeId: bookmarkeeId]
}
...
}
此方法使用表“书签”存储员工之间的关系,因此可以让2个人为同一员工添加书签。 请注意,Bookmark类必须实现Serializable。
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