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Save child and parent at the same time

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0

I need to save 2 models at the same time in the transaction, but...

org.postgresql.util.PSQLException: ERROR: null value in column "book_id" violates not-null constraint

I don't understand what is going wrong. My models:

a) Chapter

@Entity
class Chapter() : AuditModel() 

constructor(number: Int, title: String) : this() 
 this.number = number
 this.title = title


@Column(nullable = false)
var number: Int? = null

@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
var progress: Int = 0

@ManyToOne
@JoinColumn(name = "book_id")
lateinit var book: Book

b) Book

@Entity
class Book() : AuditModel() 

constructor(title: String, author: String) : this() 
 this.title = title
 this.author = author


@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
lateinit var author: String

@OneToMany(mappedBy = "book", cascade = [CascadeType.PERSIST])
val chapters: MutableSet<Chapter> = HashSet()

And function where I save models:

@Transactional
fun createBook(title: String, author: String): Boolean 
 val book = Book(title, author)
 val chapter = Chapter(1, "Example - 1")
 book.chapters.add(chapter)

 return bookRepository.save(book) != null

How to fix it? I'm new in Spring and it's totally incomprehensible to me.

spring kotlin relationship

share|improve this question

asked Mar 23 at 11:03

LookBadLookBad

227

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It's extremely simple: the column chapter.book_id is mapped by the property Chapter.book. Chapter.book is null (i.e. never initialized anywhere). So the column is also set to null. And since your database table doesn't allow that, you get an exception.
  
  – JB Nizet
  Mar 23 at 11:07
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  lel? It's should work automatically? I added a new chapter to book.chapters, this chapter should know about book_id - or shouldn't?
  
  – LookBad
  Mar 23 at 11:18
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  No, it shouldn't. It's your responsibility to keep both sides of the association in coherence, and the owner side is chapter.book, so JPA doesn't care about book.chapters
  
  – JB Nizet
  Mar 23 at 11:24
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How to change it?
  
  – LookBad
  Mar 23 at 11:35
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  chapter.book = book
  
  – JB Nizet
  Mar 23 at 11:51
  

  
  
  
  

 | 
show 3 more comments

0

I need to save 2 models at the same time in the transaction, but...

org.postgresql.util.PSQLException: ERROR: null value in column "book_id" violates not-null constraint

I don't understand what is going wrong. My models:

a) Chapter

@Entity
class Chapter() : AuditModel() 

constructor(number: Int, title: String) : this() 
 this.number = number
 this.title = title


@Column(nullable = false)
var number: Int? = null

@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
var progress: Int = 0

@ManyToOne
@JoinColumn(name = "book_id")
lateinit var book: Book

b) Book

@Entity
class Book() : AuditModel() 

constructor(title: String, author: String) : this() 
 this.title = title
 this.author = author


@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
lateinit var author: String

@OneToMany(mappedBy = "book", cascade = [CascadeType.PERSIST])
val chapters: MutableSet<Chapter> = HashSet()

And function where I save models:

@Transactional
fun createBook(title: String, author: String): Boolean 
 val book = Book(title, author)
 val chapter = Chapter(1, "Example - 1")
 book.chapters.add(chapter)

 return bookRepository.save(book) != null

How to fix it? I'm new in Spring and it's totally incomprehensible to me.

spring kotlin relationship

share|improve this question

asked Mar 23 at 11:03

LookBadLookBad

227

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It's extremely simple: the column chapter.book_id is mapped by the property Chapter.book. Chapter.book is null (i.e. never initialized anywhere). So the column is also set to null. And since your database table doesn't allow that, you get an exception.
  
  – JB Nizet
  Mar 23 at 11:07
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  lel? It's should work automatically? I added a new chapter to book.chapters, this chapter should know about book_id - or shouldn't?
  
  – LookBad
  Mar 23 at 11:18
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  No, it shouldn't. It's your responsibility to keep both sides of the association in coherence, and the owner side is chapter.book, so JPA doesn't care about book.chapters
  
  – JB Nizet
  Mar 23 at 11:24
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How to change it?
  
  – LookBad
  Mar 23 at 11:35
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  chapter.book = book
  
  – JB Nizet
  Mar 23 at 11:51
  

  
  
  
  

 | 
show 3 more comments

I need to save 2 models at the same time in the transaction, but...

org.postgresql.util.PSQLException: ERROR: null value in column "book_id" violates not-null constraint

I don't understand what is going wrong. My models:

a) Chapter

@Entity
class Chapter() : AuditModel() 

constructor(number: Int, title: String) : this() 
 this.number = number
 this.title = title


@Column(nullable = false)
var number: Int? = null

@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
var progress: Int = 0

@ManyToOne
@JoinColumn(name = "book_id")
lateinit var book: Book

b) Book

@Entity
class Book() : AuditModel() 

constructor(title: String, author: String) : this() 
 this.title = title
 this.author = author


@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
lateinit var author: String

@OneToMany(mappedBy = "book", cascade = [CascadeType.PERSIST])
val chapters: MutableSet<Chapter> = HashSet()

And function where I save models:

@Transactional
fun createBook(title: String, author: String): Boolean 
 val book = Book(title, author)
 val chapter = Chapter(1, "Example - 1")
 book.chapters.add(chapter)

 return bookRepository.save(book) != null

How to fix it? I'm new in Spring and it's totally incomprehensible to me.

spring kotlin relationship

share|improve this question

asked Mar 23 at 11:03

LookBadLookBad

227

org.postgresql.util.PSQLException: ERROR: null value in column "book_id" violates not-null constraint

@Entity
class Chapter() : AuditModel() 

constructor(number: Int, title: String) : this() 
 this.number = number
 this.title = title


@Column(nullable = false)
var number: Int? = null

@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
var progress: Int = 0

@ManyToOne
@JoinColumn(name = "book_id")
lateinit var book: Book

@Entity
class Book() : AuditModel() 

constructor(title: String, author: String) : this() 
 this.title = title
 this.author = author


@Column(nullable = false)
lateinit var title: String

@Column(nullable = false)
lateinit var author: String

@OneToMany(mappedBy = "book", cascade = [CascadeType.PERSIST])
val chapters: MutableSet<Chapter> = HashSet()

@Transactional
fun createBook(title: String, author: String): Boolean 
 val book = Book(title, author)
 val chapter = Chapter(1, "Example - 1")
 book.chapters.add(chapter)

 return bookRepository.save(book) != null

share|improve this question

asked Mar 23 at 11:03

LookBadLookBad

227

share|improve this question

asked Mar 23 at 11:03

LookBadLookBad

227

asked Mar 23 at 11:03

LookBadLookBad

227

asked Mar 23 at 11:03

LookBadLookBad

227