carlosarli
Constraint error when attempting to delete struct
Hello everyone,
I have the following models and changesets for users and addresses:
user.ex
schema "users" do
field :title, :string
field :f_name, :string
field :l_name, :string
field :DOB, :date
field :email, :string
field :username, :string
field :password, :string, virtual: true
field :password_confirmation, :string, virtual: true
field :password_hash, :string
field :image, Assistant.Image.Type
#associations
has_one :addresses, Assistant.Web.Address
has_many :appointment, Assistant.Web.Appointment
belongs_to :role, Assistant.Web.Role
timestamps()
end
#checks the changeset of the controller to see whether the input matches the rules I set here
def changeset(model, params \\ :invalid) do
model
|> cast(params, ~w(title f_name l_name DOB email username role_id))
|> cast_attachments(params, [:image])
|> validate_required([:title, :f_name, :l_name, :DOB, :email, :username, :role_id, :image])
|> validate_length(:username, min: 2, max: 20)
|> unique_constraint(:username)
|> assoc_constraint(:role)
|> cast_assoc(:addresses, required: true)
end
Address.ex
schema "addresses" do
field :house_n, :integer
field :address_1, :string
field :address_2, :string
field :post_code, :string
field :city, :string
field :county, :string
field :country, :string
belongs_to :user, Assistant.Web.User, foreign_key: :user_id
timestamps()
end
@doc """
Builds a changeset based on the `struct` and `params`.
"""
def changeset(struct, params \\ %{}) do
struct
|> cast(params, [:house_n, :address_1, :address_2, :post_code, :city, :county, :country])
|> validate_required([:house_n, :address_1, :address_2, :post_code, :city, :county, :country])
end
When I try to delete a new user I have created it gives me this error:
constraint error when attempting to delete struct:
- foreign_key: addresses_user_id_fkey
I have searched through the forum and on stack overflow and the solution seems to be to add the foreign_key_constraint(), but I am not exactly clear on how to go on about it as I have tried following the suggestions, but so far I keep getting the same error. Has it got anything to do with the cast_assoc()? I’ve got that from the book programming phoenix but online I found varying opinions on it so I thought maybe that could be the issue.
Thank you for your help ![]()
Most Liked
kokolegorille
Maybe You could set the on_delete option between user and its addresses association.
By default, it will do nothing… Thus I think it is why You get this error.
For this to work, You could look at
https://hexdocs.pm/ecto/Ecto.Migration.html#references/2
and
This would be in your addresses migration
add :user_id, references("users"), on_delete: :delete_all
and in the schema
has_one :addresses, Assistant.Web.Address, on_delete: :delete_all
It is not tested, but it might help…
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