Relations Demo

relations.go

package main

import (
	"fmt"

	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

type Student struct {
	gorm.Model
	Name    string
	Parents []Parent `gorm:"many2many:relations;"`
}

type Parent struct {
	gorm.Model
	Name string
}

type Relation struct {
	StudentID uint `gorm:"primaryKey"`
	ParentID  uint `gorm:"primaryKey"`
	Relation  string
}

func main() {
	st1 := Student{Name: "朱高炽"}
	st2 := Student{Name: "朱玉英"}
	st3 := Student{Name: "徐景昌"}

	pa1 := Parent{Name: "朱元璋"}
	pa2 := Parent{Name: "马秀英"}
	pa3 := Parent{Name: "徐达"}
	pa4 := Parent{Name: "徐增寿"}
	pa5 := Parent{Name: "朱棣"}
	pa6 := Parent{Name: "徐氏"}

	db, err := gorm.Open(sqlite.Open("relations.db"), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Info),
	})
	if err != nil {
		panic(err)
	}
	db.AutoMigrate(&Student{}, &Parent{}, &Relation{})
	db.Create(&st1)
	db.Create(&st2)
	db.Create(&st3)

	db.Create(&pa1)
	db.Create(&pa2)
	db.Create(&pa3)
	db.Create(&pa4)
	db.Create(&pa5)
	db.Create(&pa6)
	fmt.Println(st1)

	db.Create(&Relation{StudentID: st1.ID, ParentID: pa1.ID, Relation: "爷爷"})
	db.Create(&Relation{StudentID: st1.ID, ParentID: pa2.ID, Relation: "奶奶"})
	db.Create(&Relation{StudentID: st1.ID, ParentID: pa5.ID, Relation: "爸爸"})
	db.Create(&Relation{StudentID: st1.ID, ParentID: pa6.ID, Relation: "妈妈"})

	db.Create(&Relation{StudentID: st2.ID, ParentID: pa1.ID, Relation: "爷爷"})
	db.Create(&Relation{StudentID: st2.ID, ParentID: pa2.ID, Relation: "奶奶"})
	db.Create(&Relation{StudentID: st2.ID, ParentID: pa5.ID, Relation: "爸爸"})
	db.Create(&Relation{StudentID: st2.ID, ParentID: pa6.ID, Relation: "妈妈"})

	db.Create(&Relation{StudentID: st3.ID, ParentID: pa3.ID, Relation: "爷爷"})
	db.Create(&Relation{StudentID: st3.ID, ParentID: pa4.ID, Relation: "爸爸"})

	db.Create(&Relation{StudentID: st1.ID, ParentID: pa3.ID, Relation: "外公"})
	db.Create(&Relation{StudentID: st2.ID, ParentID: pa3.ID, Relation: "外公"})

}

/*
> select students.id, students.name, relations.relation, parents.id, parents.name from students join relations on students.id=relations.student_id join parents on parents.id = relations.parent_id where parents.id=3;
3|徐景昌|爷爷|3|徐达
1|朱高炽|外公|3|徐达
2|朱玉英|外公|3|徐达
> select students.id, students.name, relations.relation, parents.id, parents.name from students join relations on students.id=relations.student_id join parents on parents.id = relations.parent_id where students.id=1;
1|朱高炽|爷爷|1|朱元璋
1|朱高炽|奶奶|2|马秀英
1|朱高炽|外公|3|徐达
1|朱高炽|爸爸|5|朱棣
1|朱高炽|妈妈|6|徐氏
*/