AF
Ash Framework•4mo ago
Vahagn

`on_match: :error` should error on unique key violation?

Hi, I want to make an invitation accept action, invitation has a relationship member which is a belongs_to from Member, it has user_id, entity_id, which is a unique pair, I want to make accept create a :member relationship, so if a user accepts an invitation that is already in entity, it will throw unique identity violation This is what I have 
    update :accept_for_doctor do
      argument :code, :string, allow_nil?: false

      validate attribute_equals(:role, :doctor)
      validate attribute_equals(:code, arg(:code))
      validate attributes_absent(:member_id)

# this is not so important
      change relation(:accepted_doctor, %{user_id: actor(:id), entity_id: attr(:entity_id)},
               on_lookup: :relate,
               on_no_match: :error,
               on_match: :error,
               on_missing: :ignore
             )

# this should create a member, if it does not exist, or error out
# `relation` function just does manage_relationship with the values provided
      change relation(:member, %{user_id: actor(:id), role: :doctor},
               use_identities: [:user_id, :entity_id],
               on_lookup: :relate,
               on_no_match: :create,
               on_match: :error
             )
    end
    update :accept_for_doctor do
      argument :code, :string, allow_nil?: false

      validate attribute_equals(:role, :doctor)
      validate attribute_equals(:code, arg(:code))
      validate attributes_absent(:member_id)

# this is not so important
      change relation(:accepted_doctor, %{user_id: actor(:id), entity_id: attr(:entity_id)},
               on_lookup: :relate,
               on_no_match: :error,
               on_match: :error,
               on_missing: :ignore
             )

# this should create a member, if it does not exist, or error out
# `relation` function just does manage_relationship with the values provided
      change relation(:member, %{user_id: actor(:id), role: :doctor},
               use_identities: [:user_id, :entity_id],
               on_lookup: :relate,
               on_no_match: :create,
               on_match: :error
             )
    end
4 Replies
ZachDaniel
ZachDaniel•4mo ago
have you looked at the relationships guide? There is a section on manage_relationship. Did an LLM give you that change relation code? That isn't a function https://hexdocs.pm/ash/relationships.html#using-change-manage_relationship-3-in-actions https://hexdocs.pm/ash/Ash.Changeset.html#manage_relationship/4
Vahagn
VahagnOP•4mo ago
Yes I have looked into that. I have created a function that returns my change module, which only calls manage_relationship with the same values as I passed them I just want to know if I pass on_match: :error to Changeset.manage_relationship, shouldn't it error out if it finds a record matching the identity?
ZachDaniel
ZachDaniel•4mo ago
It should yes. Did you try it? use_identities: [:identity_name]
Vahagn
VahagnOP•4mo ago
oh. I thought it is an array that accepts attributes will try thanks

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