How to store enum data as Array List in a database using Kotlin - spring-boot

Question

I have an enum class that contain multiple data ,I want to store that
enum data as list in database. for example Developer table it contain
technology column ,that column store enum data, Suppose one user want
to store Developer1 working on many technologies like java , Kotllin ,
.Net etc these technologies are belongs from enum class , How to store
.
Same as I have a Subject enum class that contain multiple subject name
,When I Register a new teacher then I want to store how many subjects
teacher know ,If he know multiple subjects that present in our enum
class list then store the subjects id which known by the teacher.But I
am not able to store multiple data in a single column in subjectId ,It
store only one Data in SubjectId column,If I pass multiple data in
subjectId column in postman it throws error 400
teacherEntity class
package com.nilmani.jpqlprojectexample.entity
import com.nilmani.jpqlprojectexample.enum.Subject
import com.nilmani.jpqlprojectexample.enum.University
import java.util.*
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.GenerationType
import javax.persistence.Id
#Entity
data class Teacher(
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
val id:Long=-1,
val nameOfTeacher:String="",
val price:Long=-1,
val subject:Int = Subject.MATH.type,//List<Int> = listOf(Subject.MATH.type)
val university:Int=University.OTHER.type
)
Subject enum class
package com.nilmani.jpqlprojectexample.enum
enum class Subject(val type:Int) {
MATH(1),
PHYSIC(2),
ACCOUNTING(3),
ZOOLOGY(4),
BIOLOGY(5),
PROGRAMMING(6),
STATICS(7),
CHEMISTRY(8),
HISTORY(9)
}
ReqTeacher Model class
package com.nilmani.jpqlprojectexample.model.request
import com.nilmani.jpqlprojectexample.enum.Subject import com.nilmani.jpqlprojectexample.enum.University
data class ReqTeacher(
val nameOfTeacher:String="",
val price:Long=-1,
val subject:Int= Subject.MATH.type,
val university:Int= University.OTHER.type, )
Response Teacher Model class
package com.nilmani.jpqlprojectexample.model.response
import com.nilmani.jpqlprojectexample.enum.Subject
import com.nilmani.jpqlprojectexample.enum.University
data class ResTeacher(
val nameOfTeacher:String="",
val price:Long=-1,
val subject:Int= Subject.MATH.type,
val university:Int= University.OTHER.type,
)
Teacher controller class
package com.nilmani.jpqlprojectexample.controller
import com.nilmani.jpqlprojectexample.entity.Teacher
import com.nilmani.jpqlprojectexample.model.request.ReqTeacher
import com.nilmani.jpqlprojectexample.model.response.ResTeacher
import com.nilmani.jpqlprojectexample.repository.TeacherRepository
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.http.HttpStatus
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.*
#RestController
#RequestMapping("/teachTest")
class TeacherController {
#Autowired
private lateinit var teachRopo:TeacherRepository
#PostMapping("/add")
fun addTeacher(#ModelAttribute request:ReqTeacher):ResponseEntity<*>{
// val newTeacher = teachRopo.findById(request.)
var newTeacher = Teacher(
nameOfTeacher = request.nameOfTeacher,
price = request.price,
subject = request.subject,
university = request.university,
)
val saveTeacher = teachRopo.save(newTeacher)
val respTeacher = ResTeacher(
saveTeacher.nameOfTeacher,
saveTeacher.price,
saveTeacher.subject,
saveTeacher.university
)
return ResponseEntity(respTeacher,HttpStatus.OK)
}
}
I want to store multiple data or single data in SubjectId column of a
particular teacherId,But My code store only one data for a particular
teacherId

Answer 1

You should have a new table (Entity) that represents the 1-to-many relationship between Teacher and Subject, e.g. teacher_subject. This is the proper approach. If you attempt to store the subjects as space/comma-separated values in a single cell, e.g. "math, physics, biology" that would be bad practice.