I want to have add more tags to the post by this way ```post.tags.add(existedTag) postRepo.save(pos...

# server

[minhnhat]

I want to have add more tags to the post by this way

post.tags.add(existedTag)
postRepo.save(post)

but It didn't work

[Mikhail]

Send here your Post JPA entity (that owns the relationship)

[minhnhat]

this is my user-role case, It have the same issue

@Entity
class Userr {
    @Id
    @GeneratedValue
    var id: Long? = null

    var name: String? = null

    @OneToMany(mappedBy = "user", cascade = [CascadeType.PERSIST])
    var roles: MutableList<Role> = mutableListOf()
}

@Entity
class Role {
    @Id
    @GeneratedValue
    var id: Long? = null

    var name: String? = null

    @ManyToOne
    @JsonIgnore
    var user: Userr? = null
}

[Mikhail]

does it work with saveAndFlush ? Do you use @Transactional ?

[minhnhat]

I don't use @Transactional

let me try with saveAndFlush

[minhnhat]

Transactional doesn't work

and I can't call saveAndFlush

[Mikhail]

I wouldn't use @OneToMany , because it's logically incorrect, a single post can have many tags and a tag itself can associate with multiple posts, this is @ManyToMany . But, try this:

<http://existedTag.post|existedTag.post> = post
post.tags.add(existedTag)
postRepo.save(post)

[minhnhat]

yes, you are right, I just demonstrate the issue.

think about another example. User will have list of addresses

how can I easy add new address to user

val newAddress = Address()
newAddress.user = user // redundant
user.addresses.add(newAddress)
userRepo.save(user)

but if this is the only way to work in kotlin, I'm ok

BTW, thank you very much @Mikhail

[minhnhat]

what I'm missing is JoinColumn in OneToMany and cascade = [CascadeType.All]