import Ecto.Query, only: [from: 1, from: 2, join: 4, join: 5, distinct: 3, where: 3]
defmodule Ecto.Association.NotLoaded do
@moduledoc """
Struct returned by associations when they are not loaded.
The fields are:
* `__field__` - the association field in `owner`
* `__owner__` - the schema that owns the association
* `__cardinality__` - the cardinality of the association
"""
@type t :: %__MODULE__{
__field__: atom(),
__owner__: any(),
__cardinality__: atom()
}
defstruct [:__field__, :__owner__, :__cardinality__]
defimpl Inspect do
def inspect(not_loaded, _opts) do
msg = "association #{inspect not_loaded.__field__} is not loaded"
~s(#Ecto.Association.NotLoaded<#{msg}>)
end
end
end
defmodule Ecto.Association do
@moduledoc false
@type t :: %{required(:__struct__) => atom,
required(:on_cast) => nil | fun,
required(:cardinality) => :one | :many,
required(:relationship) => :parent | :child,
required(:owner) => atom,
required(:owner_key) => atom,
required(:field) => atom,
required(:unique) => boolean,
optional(atom) => any}
alias Ecto.Query.Builder.OrderBy
@doc """
Helper to check if a queryable is compiled.
"""
def ensure_compiled(queryable, env) do
if not is_atom(queryable) or queryable in env.context_modules do
:skip
else
case Code.ensure_compiled(queryable) do
{:module, _} -> :compiled
{:error, :unavailable} -> :skip
{:error, _} -> :not_found
end
end
end
@doc """
Builds the association struct.
The struct must be defined in the module that implements the
callback and it must contain at least the following keys:
* `:cardinality` - tells if the association is one to one
or one/many to many
* `:field` - tells the field in the owner struct where the
association should be stored
* `:owner` - the owner module of the association
* `:owner_key` - the key in the owner with the association value
* `:relationship` - if the relationship to the specified schema is
of a `:child` or a `:parent`
"""
@callback struct(module, field :: atom, opts :: Keyword.t) :: t
@doc """
Invoked after the schema is compiled to validate associations.
Useful for checking if associated modules exist without running
into deadlocks.
"""
@callback after_compile_validation(t, Macro.Env.t) :: :ok | {:error, String.t}
@doc """
Builds a struct for the given association.
The struct to build from is given as argument in case default values
should be set in the struct.
Invoked by `Ecto.build_assoc/3`.
"""
@callback build(t, owner :: Ecto.Schema.t, %{atom => term} | [Keyword.t]) :: Ecto.Schema.t
@doc """
Returns an association join query.
This callback receives the association struct and it must return
a query that retrieves all associated entries using joins up to
the owner association.
For example, a `has_many :comments` inside a `Post` module would
return:
from c in Comment, join: p in Post, on: c.post_id == p.id
Note all the logic must be expressed inside joins, as fields like
`where` and `order_by` won't be used by the caller.
This callback is invoked when `join: assoc(p, :comments)` is used
inside queries.
"""
@callback joins_query(t) :: Ecto.Query.t
@doc """
Returns the association query on top of the given query.
If the query is `nil`, the association target must be used.
This callback receives the association struct and it must return
a query that retrieves all associated entries with the given
values for the owner key.
This callback is used by `Ecto.assoc/2` and when preloading.
"""
@callback assoc_query(t, Ecto.Query.t | nil, values :: [term]) :: Ecto.Query.t
@doc """
Returns information used by the preloader.
"""
@callback preload_info(t) ::
{:assoc, t, {integer, atom} | {integer, atom, Ecto.Type.t()}} | {:through, t, [atom]}
@doc """
Performs the repository change on the association.
Receives the parent changeset, the current changesets
and the repository action options. Must return the
persisted struct (or nil) or the changeset error.
"""
@callback on_repo_change(t, parent :: Ecto.Changeset.t, changeset :: Ecto.Changeset.t, Ecto.Adapter.t, Keyword.t) ::
{:ok, Ecto.Schema.t | nil} | {:error, Ecto.Changeset.t}
@doc """
Retrieves the association from the given schema.
"""
def association_from_schema!(schema, assoc) do
schema.__schema__(:association, assoc) ||
raise ArgumentError, "schema #{inspect schema} does not have association #{inspect assoc}"
end
@doc """
Returns the association key for the given module with the given suffix.
## Examples
iex> Ecto.Association.association_key(Hello.World, :id)
:world_id
iex> Ecto.Association.association_key(Hello.HTTP, :id)
:http_id
iex> Ecto.Association.association_key(Hello.HTTPServer, :id)
:http_server_id
"""
def association_key(module, suffix) do
prefix = module |> Module.split |> List.last |> Macro.underscore
:"#{prefix}_#{suffix}"
end
@doc """
Build an association query through the given associations from the specified owner table
and through the given associations. Finally filter by the provided values of the owner_key of
the first relationship in the chain. Used in Ecto.assoc/2.
"""
def filter_through_chain(owner, through, values) do
chain_through(owner, through, nil, values)
|> distinct([x], true)
end
@doc """
Join the target table given a list of associations to go through starting from the owner table.
"""
def join_through_chain(owner, through, query) do
chain_through(owner, through, query, nil)
end
# This function is used by both join_through_chain/3 and filter_through_chain/3 since the algorithm for both
# is nearly identical barring a few differences.
defp chain_through(owner, through, join_to, values) do
# Flatten the chain of throughs. If any of the associations is a HasThrough this allows us to expand it so we have
# a list of atomic associations to join through.
{_, through} = flatten_through_chain(owner, through, [])
# If we're joining then we're going forward from the owner table to the destination table.
# Otherwise we're going backward from the destination table then filtering by values.
chain_direction = if(join_to != nil, do: :forward, else: :backward)
# This stage produces a list of joins represented as a keyword list with the following structure:
# [
# [schema: (The Schema), in_key: (The key used to join into the table), out_key: (The key used to join with the next), where: (The condition KW list)]
# ]
relation_list = resolve_through_tables(owner, through, chain_direction)
# Filter out the joins which are redundant
filtered_list = Enum.with_index(relation_list)
|> Enum.filter(fn
# We always keep the first table in the chain since it's our source table for the query
{_, 0} -> true
{rel, _} ->
# If the condition is not empty we need to join to the table. Otherwise if the in_key and out_key is the same
# then this join is redundant since we can just join to the next table in the chain.
rel.in_key != rel.out_key or rel.where != []
end)
|> Enum.map(&elem(&1, 0))
# If we're preloading we don't need the last table since it is the owner table.
filtered_list = if(join_to == nil, do: Enum.slice(filtered_list, 0..-2), else: filtered_list)
[source | joins] = filtered_list
source_schema = source.schema
query = join_to || from(s in source_schema)
counter = Ecto.Query.Builder.count_binds(query) - 1
# We need to create the query by joining all the tables, and also we need the out_key of the final table to use
# for the final WHERE clause with values.
{_, query, _, dest_out_key} = Enum.reduce(joins, {source, query, counter, source.out_key}, fn curr_rel, {prev_rel, query, counter, _} ->
related_queryable = curr_rel.schema
next = join(query, :inner, [{src, counter}], dest in ^related_queryable, on: field(src, ^prev_rel.out_key) == field(dest, ^curr_rel.in_key))
|> combine_joins_query(curr_rel.where, counter + 1)
{curr_rel, next, counter + 1, curr_rel.out_key}
end)
final_bind = Ecto.Query.Builder.count_binds(query) - 1
values = List.wrap(values)
query = case {join_to, values} do
{nil, [single_value]} ->
query
|> where([{dest, final_bind}], field(dest, ^dest_out_key) == ^single_value)
{nil, values} ->
query
|> where([{dest, final_bind}], field(dest, ^dest_out_key) in ^values)
{_, _} ->
query
end
combine_assoc_query(query, source.where || [])
end
defp flatten_through_chain(owner, [], acc), do: {owner, acc}
defp flatten_through_chain(owner, [assoc | tl], acc) do
refl = association_from_schema!(owner, assoc)
case refl do
%{through: nested_throughs} ->
{owner, acc} = flatten_through_chain(owner, nested_throughs, acc)
flatten_through_chain(owner, tl, acc)
_ ->
flatten_through_chain(refl.related, tl, acc ++ [assoc])
end
end
defp resolve_through_tables(owner, through, :backward) do
# This step generates a list of maps with the following keys:
# [
# %{schema: ..., out_key: ..., in_key: ..., where: ...}
# ]
# This is a list of all tables that we will need to join to follow the chain of throughs and which key is used
# to join in and out of the table, along with the where condition for that table. The final table of the chain will
# be "owner", and the first table of the chain will be the final destination table of all the throughs.
initial_owner_map = %{schema: owner, out_key: nil, in_key: nil, where: nil}
Enum.reduce(through, {owner, [initial_owner_map]}, fn assoc, {owner, table_list} ->
refl = association_from_schema!(owner, assoc)
[owner_map | table_list] = table_list
table_list = case refl do
%{join_through: join_through, join_keys: join_keys, join_where: join_where, where: where} ->
[{owner_join_key, owner_key}, {related_join_key, related_key}] = join_keys
owner_map = %{owner_map | in_key: owner_key}
join_map = %{schema: join_through, out_key: owner_join_key, in_key: related_join_key, where: join_where}
related_map = %{schema: refl.related, out_key: related_key, in_key: nil, where: where}
[related_map, join_map, owner_map | table_list]
_ ->
owner_map = %{owner_map | in_key: refl.owner_key}
related_map = %{schema: refl.related, out_key: refl.related_key, in_key: nil, where: refl.where}
[related_map, owner_map | table_list]
end
{refl.related, table_list}
end)
|> elem(1)
end
defp resolve_through_tables(owner, through, :forward) do
# In the forward case (joining) we need to reverse the list and swap the in_key for the out_key
# since we've changed directions.
resolve_through_tables(owner, through, :backward)
|> Enum.reverse()
|> Enum.map(fn %{out_key: out_key, in_key: in_key} = join ->
%{join | out_key: in_key, in_key: out_key}
end)
end
@doc """
Add the default assoc query where clauses to a join.
This handles only `where` and converts it to a `join`,
as that is the only information propagate in join queries.
"""
def combine_joins_query(query, [], _binding), do: query
def combine_joins_query(%{joins: joins} = query, [_ | _] = conditions, binding) do
{joins, [join_expr]} = Enum.split(joins, -1)
%{on: %{params: params, expr: expr} = join_on} = join_expr
{expr, params} = expand_where(conditions, expr, Enum.reverse(params), length(params), binding)
%{query | joins: joins ++ [%{join_expr | on: %{join_on | expr: expr, params: params}}]}
end
@doc """
Add the default assoc query where clauses a provided query.
"""
def combine_assoc_query(query, []), do: query
def combine_assoc_query(%{wheres: []} = query, conditions) do
{expr, params} = expand_where(conditions, true, [], 0, 0)
%{query | wheres: [%Ecto.Query.BooleanExpr{op: :and, expr: expr, params: params, line: __ENV__.line, file: __ENV__.file}]}
end
def combine_assoc_query(%{wheres: wheres} = query, conditions) do
{wheres, [where_expr]} = Enum.split(wheres, -1)
%{params: params, expr: expr} = where_expr
{expr, params} = expand_where(conditions, expr, Enum.reverse(params), length(params), 0)
%{query | wheres: wheres ++ [%{where_expr | expr: expr, params: params}]}
end
defp expand_where(conditions, expr, params, counter, binding) do
conjoin_exprs = fn
true, r -> r
l, r-> {:and, [], [l, r]}
end
{expr, params, _counter} =
Enum.reduce(conditions, {expr, params, counter}, fn
{key, nil}, {expr, params, counter} ->
expr = conjoin_exprs.(expr, {:is_nil, [], [to_field(binding, key)]})
{expr, params, counter}
{key, {:not, nil}}, {expr, params, counter} ->
expr = conjoin_exprs.(expr, {:not, [], [{:is_nil, [], [to_field(binding, key)]}]})
{expr, params, counter}
{key, {:fragment, frag}}, {expr, params, counter} when is_binary(frag) ->
pieces = Ecto.Query.Builder.fragment_pieces(frag, [to_field(binding, key)])
expr = conjoin_exprs.(expr, {:fragment, [], pieces})
{expr, params, counter}
{key, {:in, value}}, {expr, params, counter} when is_list(value) ->
expr = conjoin_exprs.(expr, {:in, [], [to_field(binding, key), {:^, [], [counter]}]})
{expr, [{value, {:in, {binding, key}}} | params], counter + 1}
{key, value}, {expr, params, counter} ->
expr = conjoin_exprs.(expr, {:==, [], [to_field(binding, key), {:^, [], [counter]}]})
{expr, [{value, {binding, key}} | params], counter + 1}
end)
{expr, Enum.reverse(params)}
end
defp to_field(binding, field),
do: {{:., [], [{:&, [], [binding]}, field]}, [], []}
@doc """
Build a join query with the given `through` associations starting at `counter`.
"""
def joins_query(query, through, counter) do
Enum.reduce(through, {query, counter}, fn current, {acc, counter} ->
query = join(acc, :inner, [{x, counter}], assoc(x, ^current))
{query, counter + 1}
end) |> elem(0)
end
@doc """
Retrieves related module from queryable.
## Examples
iex> Ecto.Association.related_from_query({"custom_source", Schema}, :comments_v1)
Schema
iex> Ecto.Association.related_from_query(Schema, :comments_v1)
Schema
iex> Ecto.Association.related_from_query("wrong", :comments_v1)
** (ArgumentError) association :comments_v1 queryable must be a schema or a {source, schema}. got: "wrong"
"""
def related_from_query(atom, _name) when is_atom(atom), do: atom
def related_from_query({source, schema}, _name) when is_binary(source) and is_atom(schema), do: schema
def related_from_query(queryable, name) do
raise ArgumentError, "association #{inspect name} queryable must be a schema or " <>
"a {source, schema}. got: #{inspect queryable}"
end
@doc """
Applies default values into the struct.
"""
def apply_defaults(struct, defaults, _owner) when is_list(defaults) do
struct(struct, defaults)
end
def apply_defaults(struct, {mod, fun, args}, owner) do
apply(mod, fun, [struct.__struct__, owner | args])
end
@doc """
Validates `defaults` for association named `name`.
"""
def validate_defaults!(_module, _name, {mod, fun, args} = defaults)
when is_atom(mod) and is_atom(fun) and is_list(args),
do: defaults
def validate_defaults!(module, _name, fun) when is_atom(fun),
do: {module, fun, []}
def validate_defaults!(_module, _name, defaults) when is_list(defaults),
do: defaults
def validate_defaults!(_module, name, defaults) do
raise ArgumentError,
"expected defaults for #{inspect name} to be a keyword list " <>
"or a {module, fun, args} tuple, got: `#{inspect defaults}`"
end
@doc """
Validates `preload_order` for association named `name`.
"""
def validate_preload_order!(name, preload_order) when is_list(preload_order) do
Enum.map(preload_order, fn
field when is_atom(field) ->
field
{direction, field} when is_atom(direction) and is_atom(field) ->
unless OrderBy.valid_direction?(direction) do
raise ArgumentError,
"expected `:preload_order` for #{inspect name} to be a keyword list or a list of atoms/fields, " <>
"got: `#{inspect preload_order}`, " <>
"`#{inspect direction}` is not a valid direction"
end
{direction, field}
item ->
raise ArgumentError,
"expected `:preload_order` for #{inspect name} to be a keyword list or a list of atoms/fields, " <>
"got: `#{inspect preload_order}`, " <>
"`#{inspect item}` is not valid"
end)
end
def validate_preload_order!(name, preload_order) do
raise ArgumentError,
"expected `:preload_order` for #{inspect name} to be a keyword list or a list of atoms/fields, " <>
"got: `#{inspect preload_order}`"
end
@doc """
Merges source from query into to the given schema.
In case the query does not have a source, returns
the schema unchanged.
"""
def merge_source(schema, query)
def merge_source(%{__meta__: %{source: source}} = struct, {source, _}) do
struct
end
def merge_source(struct, {source, _}) do
Ecto.put_meta(struct, source: source)
end
def merge_source(struct, _query) do
struct
end
@doc """
Updates the prefix of a changeset based on the metadata.
"""
def update_parent_prefix(
%{data: %{__meta__: %{prefix: prefix}}} = changeset,
%{__meta__: %{prefix: prefix}}
),
do: changeset
def update_parent_prefix(
%{data: %{__meta__: %{prefix: nil}}} = changeset,
%{__meta__: %{prefix: prefix}}
),
do: update_in(changeset.data, &Ecto.put_meta(&1, prefix: prefix))
def update_parent_prefix(changeset, _),
do: changeset
@doc """
Performs the repository action in the related changeset,
returning `{:ok, data}` or `{:error, changes}`.
"""
def on_repo_change(%{data: struct}, [], _adapter, _opts) do
{:ok, struct}
end
def on_repo_change(changeset, assocs, adapter, opts) do
%{data: struct, changes: changes, action: action} = changeset
{struct, changes, _halt, valid?} =
Enum.reduce(assocs, {struct, changes, false, true}, fn {refl, value}, acc ->
on_repo_change(refl, value, changeset, action, adapter, opts, acc)
end)
case valid? do
true -> {:ok, struct}
false -> {:error, changes}
end
end
defp on_repo_change(%{cardinality: :one, field: field} = meta, nil, parent_changeset,
_repo_action, adapter, opts, {parent, changes, halt, valid?}) do
if not halt, do: maybe_replace_one!(meta, nil, parent, parent_changeset, adapter, opts)
{Map.put(parent, field, nil), Map.put(changes, field, nil), halt, valid?}
end
defp on_repo_change(%{cardinality: :one, field: field, __struct__: mod} = meta,
%{action: action, data: current} = changeset, parent_changeset,
repo_action, adapter, opts, {parent, changes, halt, valid?}) do
check_action!(meta, action, repo_action)
if not halt, do: maybe_replace_one!(meta, current, parent, parent_changeset, adapter, opts)
case on_repo_change_unless_halted(halt, mod, meta, parent_changeset, changeset, adapter, opts) do
{:ok, struct} ->
{Map.put(parent, field, struct), Map.put(changes, field, changeset), halt, valid?}
{:error, error_changeset} ->
{parent, Map.put(changes, field, error_changeset),
halted?(halt, changeset, error_changeset), false}
end
end
defp on_repo_change(%{cardinality: :many, field: field, __struct__: mod} = meta,
changesets, parent_changeset, repo_action, adapter, opts,
{parent, changes, halt, all_valid?}) do
{changesets, structs, halt, valid?} =
Enum.reduce(changesets, {[], [], halt, true}, fn
%{action: action} = changeset, {changesets, structs, halt, valid?} ->
check_action!(meta, action, repo_action)
case on_repo_change_unless_halted(halt, mod, meta, parent_changeset, changeset, adapter, opts) do
{:ok, nil} ->
{[changeset | changesets], structs, halt, valid?}
{:ok, struct} ->
{[changeset | changesets], [struct | structs], halt, valid?}
{:error, error_changeset} ->
{[error_changeset | changesets], structs, halted?(halt, changeset, error_changeset), false}
end
end)
if valid? do
{Map.put(parent, field, Enum.reverse(structs)),
Map.put(changes, field, Enum.reverse(changesets)),
halt, all_valid?}
else
{parent,
Map.put(changes, field, Enum.reverse(changesets)),
halt, false}
end
end
defp check_action!(%{related: schema}, :delete, :insert),
do: raise(ArgumentError, "got action :delete in changeset for associated #{inspect schema} while inserting")
defp check_action!(_, _, _), do: :ok
defp halted?(true, _, _), do: true
defp halted?(_, %{valid?: true}, %{valid?: false}), do: true
defp halted?(_, _, _), do: false
defp on_repo_change_unless_halted(true, _mod, _meta, _parent, changeset, _adapter, _opts) do
{:error, changeset}
end
defp on_repo_change_unless_halted(false, mod, meta, parent, changeset, adapter, opts) do
mod.on_repo_change(meta, parent, changeset, adapter, opts)
end
defp maybe_replace_one!(%{field: field, __struct__: mod} = meta, current, parent,
parent_changeset, adapter, opts) do
previous = Map.get(parent, field)
if replaceable?(previous) and primary_key!(previous) != primary_key!(current) do
changeset = %{Ecto.Changeset.change(previous) | action: :replace}
case mod.on_repo_change(meta, parent_changeset, changeset, adapter, opts) do
{:ok, _} ->
:ok
{:error, changeset} ->
raise Ecto.InvalidChangesetError,
action: changeset.action, changeset: changeset
end
end
end
defp maybe_replace_one!(_, _, _, _, _, _), do: :ok
defp replaceable?(nil), do: false
defp replaceable?(%Ecto.Association.NotLoaded{}), do: false
defp replaceable?(%{__meta__: %{state: :built}}), do: false
defp replaceable?(_), do: true
defp primary_key!(nil), do: []
defp primary_key!(struct), do: Ecto.primary_key!(struct)
end
defmodule Ecto.Association.Has do
@moduledoc """
The association struct for `has_one` and `has_many` associations.
Its fields are:
* `cardinality` - The association cardinality
* `field` - The name of the association field on the schema
* `owner` - The schema where the association was defined
* `related` - The schema that is associated
* `owner_key` - The key on the `owner` schema used for the association
* `related_key` - The key on the `related` schema used for the association
* `queryable` - The real query to use for querying association
* `on_delete` - The action taken on associations when schema is deleted
* `on_replace` - The action taken on associations when schema is replaced
* `defaults` - Default fields used when building the association
* `relationship` - The relationship to the specified schema, default is `:child`
* `preload_order` - Default `order_by` of the association, used only by preload
"""
@behaviour Ecto.Association
@on_delete_opts [:nothing, :nilify_all, :delete_all]
@on_replace_opts [:raise, :mark_as_invalid, :delete, :delete_if_exists, :nilify]
@has_one_on_replace_opts @on_replace_opts ++ [:update]
defstruct [:cardinality, :field, :owner, :related, :owner_key, :related_key, :on_cast,
:queryable, :on_delete, :on_replace, where: [], unique: true, defaults: [],
relationship: :child, ordered: false, preload_order: []]
@impl true
def after_compile_validation(%{queryable: queryable, related_key: related_key}, env) do
compiled = Ecto.Association.ensure_compiled(queryable, env)
cond do
compiled == :skip ->
:ok
compiled == :not_found ->
{:error, "associated schema #{inspect queryable} does not exist"}
not function_exported?(queryable, :__schema__, 2) ->
{:error, "associated module #{inspect queryable} is not an Ecto schema"}
is_nil queryable.__schema__(:type, related_key) ->
{:error, "associated schema #{inspect queryable} does not have field `#{related_key}`"}
true ->
:ok
end
end
@impl true
def struct(module, name, opts) do
queryable = Keyword.fetch!(opts, :queryable)
cardinality = Keyword.fetch!(opts, :cardinality)
related = Ecto.Association.related_from_query(queryable, name)
ref =
module
|> Module.get_attribute(:primary_key)
|> get_ref(opts[:references], name)
unless Module.get_attribute(module, :ecto_fields)[ref] do
raise ArgumentError, "schema does not have the field #{inspect ref} used by " <>
"association #{inspect name}, please set the :references option accordingly"
end
if opts[:through] do
raise ArgumentError, "invalid association #{inspect name}. When using the :through " <>
"option, the schema should not be passed as second argument"
end
on_delete = Keyword.get(opts, :on_delete, :nothing)
unless on_delete in @on_delete_opts do
raise ArgumentError, "invalid :on_delete option for #{inspect name}. " <>
"The only valid options are: " <>
Enum.map_join(@on_delete_opts, ", ", &"`#{inspect &1}`")
end
on_replace = Keyword.get(opts, :on_replace, :raise)
on_replace_opts = if cardinality == :one, do: @has_one_on_replace_opts, else: @on_replace_opts
unless on_replace in on_replace_opts do
raise ArgumentError, "invalid `:on_replace` option for #{inspect name}. " <>
"The only valid options are: " <>
Enum.map_join(@on_replace_opts, ", ", &"`#{inspect &1}`")
end
defaults = Ecto.Association.validate_defaults!(module, name, opts[:defaults] || [])
preload_order = Ecto.Association.validate_preload_order!(name, opts[:preload_order] || [])
where = opts[:where] || []
unless is_list(where) do
raise ArgumentError, "expected `:where` for #{inspect name} to be a keyword list, got: `#{inspect where}`"
end
%__MODULE__{
field: name,
cardinality: cardinality,
owner: module,
related: related,
owner_key: ref,
related_key: opts[:foreign_key] || Ecto.Association.association_key(module, ref),
queryable: queryable,
on_delete: on_delete,
on_replace: on_replace,
defaults: defaults,
where: where,
preload_order: preload_order
}
end
defp get_ref(primary_key, nil, name) when primary_key in [nil, false] do
raise ArgumentError, "need to set :references option for " <>
"association #{inspect name} when schema has no primary key"
end
defp get_ref(primary_key, nil, _name), do: elem(primary_key, 0)
defp get_ref(_primary_key, references, _name), do: references
@impl true
def build(%{owner_key: owner_key, related_key: related_key} = refl, owner, attributes) do
data = refl |> build(owner) |> struct(attributes)
%{data | related_key => Map.get(owner, owner_key)}
end
@impl true
def joins_query(%{related_key: related_key, owner: owner, owner_key: owner_key, queryable: queryable} = assoc) do
from(o in owner, join: q in ^queryable, on: field(q, ^related_key) == field(o, ^owner_key))
|> Ecto.Association.combine_joins_query(assoc.where, 1)
end
@impl true
def assoc_query(%{related_key: related_key, queryable: queryable} = assoc, query, [value]) do
from(x in (query || queryable), where: field(x, ^related_key) == ^value)
|> Ecto.Association.combine_assoc_query(assoc.where)
end
@impl true
def assoc_query(%{related_key: related_key, queryable: queryable} = assoc, query, values) do
from(x in (query || queryable), where: field(x, ^related_key) in ^values)
|> Ecto.Association.combine_assoc_query(assoc.where)
end
@impl true
def preload_info(%{related_key: related_key} = refl) do
{:assoc, refl, {0, related_key}}
end
@impl true
def on_repo_change(%{on_replace: :delete_if_exists} = refl, parent_changeset,
%{action: :replace} = changeset, adapter, opts) do
try do
on_repo_change(%{refl | on_replace: :delete}, parent_changeset, changeset, adapter, opts)
rescue
Ecto.StaleEntryError -> {:ok, nil}
end
end
def on_repo_change(%{on_replace: on_replace} = refl, %{data: parent} = parent_changeset,
%{action: :replace} = changeset, adapter, opts) do
changeset = case on_replace do
:nilify -> %{changeset | action: :update}
:update -> %{changeset | action: :update}
:delete -> %{changeset | action: :delete}
end
changeset = Ecto.Association.update_parent_prefix(changeset, parent)
case on_repo_change(refl, %{parent_changeset | data: nil}, changeset, adapter, opts) do
{:ok, _} -> {:ok, nil}
{:error, changeset} -> {:error, changeset}
end
end
def on_repo_change(assoc, parent_changeset, changeset, _adapter, opts) do
%{data: parent, repo: repo} = parent_changeset
%{action: action, changes: changes} = changeset
{key, value} = parent_key(assoc, parent)
changeset = update_parent_key(changeset, action, key, value)
changeset = Ecto.Association.update_parent_prefix(changeset, parent)
case apply(repo, action, [changeset, opts]) do
{:ok, _} = ok ->
if action == :delete, do: {:ok, nil}, else: ok
{:error, changeset} ->
original = Map.get(changes, key)
{:error, put_in(changeset.changes[key], original)}
end
end
defp update_parent_key(changeset, :delete, _key, _value),
do: changeset
defp update_parent_key(changeset, _action, key, value),
do: Ecto.Changeset.put_change(changeset, key, value)
defp parent_key(%{related_key: related_key}, nil) do
{related_key, nil}
end
defp parent_key(%{owner_key: owner_key, related_key: related_key}, owner) do
{related_key, Map.get(owner, owner_key)}
end
## Relation callbacks
@behaviour Ecto.Changeset.Relation
@impl true
def build(%{related: related, queryable: queryable, defaults: defaults}, owner) do
related
|> Ecto.Association.apply_defaults(defaults, owner)
|> Ecto.Association.merge_source(queryable)
end
## On delete callbacks
@doc false
def delete_all(refl, parent, repo_name, opts) do
if query = on_delete_query(refl, parent) do
Ecto.Repo.Queryable.delete_all repo_name, query, opts
end
end
@doc false
def nilify_all(%{related_key: related_key} = refl, parent, repo_name, opts) do
if query = on_delete_query(refl, parent) do
Ecto.Repo.Queryable.update_all repo_name, query, [set: [{related_key, nil}]], opts
end
end
defp on_delete_query(%{owner_key: owner_key, related_key: related_key,
queryable: queryable}, parent) do
if value = Map.get(parent, owner_key) do
from x in queryable, where: field(x, ^related_key) == ^value
end
end
end
defmodule Ecto.Association.HasThrough do
@moduledoc """
The association struct for `has_one` and `has_many` through associations.
Its fields are:
* `cardinality` - The association cardinality
* `field` - The name of the association field on the schema
* `owner` - The schema where the association was defined
* `owner_key` - The key on the `owner` schema used for the association
* `through` - The through associations
* `relationship` - The relationship to the specified schema, default `:child`
"""
@behaviour Ecto.Association
defstruct [:cardinality, :field, :owner, :owner_key, :through, :on_cast,
relationship: :child, unique: true, ordered: false]
@impl true
def after_compile_validation(_, _) do
:ok
end
@impl true
def struct(module, name, opts) do
through = Keyword.fetch!(opts, :through)
refl =
case through do
[h,_|_] ->
Module.get_attribute(module, :ecto_assocs)[h]
_ ->
raise ArgumentError, ":through expects a list with at least two entries: " <>
"the association in the current module and one step through, got: #{inspect through}"
end
unless refl do
raise ArgumentError, "schema does not have the association #{inspect hd(through)} " <>
"used by association #{inspect name}, please ensure the association exists and " <>
"is defined before the :through one"
end
%__MODULE__{
field: name,
cardinality: Keyword.fetch!(opts, :cardinality),
through: through,
owner: module,
owner_key: refl.owner_key,
}
end
@impl true
def build(%{field: name}, %{__struct__: owner}, _attributes) do
raise ArgumentError,
"cannot build through association `#{inspect name}` for #{inspect owner}. " <>
"Instead build the intermediate steps explicitly."
end
@impl true
def preload_info(%{through: through} = refl) do
{:through, refl, through}
end
@impl true
def on_repo_change(%{field: name}, _, _, _, _) do
raise ArgumentError,
"cannot insert/update/delete through associations `#{inspect name}` via the repository. " <>
"Instead build the intermediate steps explicitly."
end
@impl true
def joins_query(%{owner: owner, through: through}) do
Ecto.Association.join_through_chain(owner, through, from(x in owner))
end
@impl true
def assoc_query(%{owner: owner, through: through}, _, values) do
Ecto.Association.filter_through_chain(owner, through, values)
end
end
defmodule Ecto.Association.BelongsTo do
@moduledoc """
The association struct for a `belongs_to` association.
Its fields are:
* `cardinality` - The association cardinality
* `field` - The name of the association field on the schema
* `owner` - The schema where the association was defined
* `owner_key` - The key on the `owner` schema used for the association
* `related` - The schema that is associated
* `related_key` - The key on the `related` schema used for the association
* `queryable` - The real query to use for querying association
* `defaults` - Default fields used when building the association
* `relationship` - The relationship to the specified schema, default `:parent`
* `on_replace` - The action taken on associations when schema is replaced
"""
@behaviour Ecto.Association
@on_replace_opts [:raise, :mark_as_invalid, :delete, :delete_if_exists, :nilify, :update]
defstruct [:field, :owner, :related, :owner_key, :related_key, :queryable, :on_cast,
:on_replace, where: [], defaults: [], cardinality: :one, relationship: :parent,
unique: true, ordered: false]
@impl true
def after_compile_validation(%{queryable: queryable, related_key: related_key}, env) do
compiled = Ecto.Association.ensure_compiled(queryable, env)
cond do
compiled == :skip ->
:ok
compiled == :not_found ->
{:error, "associated schema #{inspect queryable} does not exist"}
not function_exported?(queryable, :__schema__, 2) ->
{:error, "associated module #{inspect queryable} is not an Ecto schema"}
is_nil queryable.__schema__(:type, related_key) ->
{:error, "associated schema #{inspect queryable} does not have field `#{related_key}`"}
true ->
:ok
end
end
@impl true
def struct(module, name, opts) do
ref = if ref = opts[:references], do: ref, else: :id
queryable = Keyword.fetch!(opts, :queryable)
related = Ecto.Association.related_from_query(queryable, name)
on_replace = Keyword.get(opts, :on_replace, :raise)
unless on_replace in @on_replace_opts do
raise ArgumentError, "invalid `:on_replace` option for #{inspect name}. " <>
"The only valid options are: " <>
Enum.map_join(@on_replace_opts, ", ", &"`#{inspect &1}`")
end
defaults = Ecto.Association.validate_defaults!(module, name, opts[:defaults] || [])
where = opts[:where] || []
unless is_list(where) do
raise ArgumentError, "expected `:where` for #{inspect name} to be a keyword list, got: `#{inspect where}`"
end
%__MODULE__{
field: name,
owner: module,
related: related,
owner_key: Keyword.fetch!(opts, :foreign_key),
related_key: ref,
queryable: queryable,
on_replace: on_replace,
defaults: defaults,
where: where
}
end
@impl true
def build(refl, owner, attributes) do
refl
|> build(owner)
|> struct(attributes)
end
@impl true
def joins_query(%{related_key: related_key, owner: owner, owner_key: owner_key, queryable: queryable} = assoc) do
from(o in owner, join: q in ^queryable, on: field(q, ^related_key) == field(o, ^owner_key))
|> Ecto.Association.combine_joins_query(assoc.where, 1)
end
@impl true
def assoc_query(%{related_key: related_key, queryable: queryable} = assoc, query, [value]) do
from(x in (query || queryable), where: field(x, ^related_key) == ^value)
|> Ecto.Association.combine_assoc_query(assoc.where)
end
@impl true
def assoc_query(%{related_key: related_key, queryable: queryable} = assoc, query, values) do
from(x in (query || queryable), where: field(x, ^related_key) in ^values)
|> Ecto.Association.combine_assoc_query(assoc.where)
end
@impl true
def preload_info(%{related_key: related_key} = refl) do
{:assoc, refl, {0, related_key}}
end
@impl true
def on_repo_change(%{on_replace: :nilify}, _, %{action: :replace}, _adapter, _opts) do
{:ok, nil}
end
def on_repo_change(%{on_replace: :delete_if_exists} = refl, parent_changeset,
%{action: :replace} = changeset, adapter, opts) do
try do
on_repo_change(%{refl | on_replace: :delete}, parent_changeset, changeset, adapter, opts)
rescue
Ecto.StaleEntryError -> {:ok, nil}
end
end
def on_repo_change(%{on_replace: on_replace} = refl, parent_changeset,
%{action: :replace} = changeset, adapter, opts) do
changeset =
case on_replace do
:delete -> %{changeset | action: :delete}
:update -> %{changeset | action: :update}
end
on_repo_change(refl, parent_changeset, changeset, adapter, opts)
end
def on_repo_change(_refl, %{data: parent, repo: repo}, %{action: action} = changeset, _adapter, opts) do
changeset = Ecto.Association.update_parent_prefix(changeset, parent)
case apply(repo, action, [changeset, opts]) do
{:ok, _} = ok ->
if action == :delete, do: {:ok, nil}, else: ok
{:error, changeset} ->
{:error, changeset}
end
end
## Relation callbacks
@behaviour Ecto.Changeset.Relation
@impl true
def build(%{related: related, queryable: queryable, defaults: defaults}, owner) do
related
|> Ecto.Association.apply_defaults(defaults, owner)
|> Ecto.Association.merge_source(queryable)
end
end
defmodule Ecto.Association.ManyToMany do
@moduledoc """
The association struct for `many_to_many` associations.
Its fields are:
* `cardinality` - The association cardinality
* `field` - The name of the association field on the schema
* `owner` - The schema where the association was defined
* `related` - The schema that is associated
* `owner_key` - The key on the `owner` schema used for the association
* `queryable` - The real query to use for querying association
* `on_delete` - The action taken on associations when schema is deleted
* `on_replace` - The action taken on associations when schema is replaced
* `defaults` - Default fields used when building the association
* `relationship` - The relationship to the specified schema, default `:child`
* `join_keys` - The keyword list with many to many join keys
* `join_through` - Atom (representing a schema) or a string (representing a table)
for many to many associations
* `join_defaults` - A list of defaults for join associations
* `preload_order` - Default `order_by` of the association, used only by preload
"""
@behaviour Ecto.Association
@on_delete_opts [:nothing, :delete_all]
@on_replace_opts [:raise, :mark_as_invalid, :delete]
defstruct [:field, :owner, :related, :owner_key, :queryable, :on_delete,
:on_replace, :join_keys, :join_through, :on_cast, where: [],
join_where: [], defaults: [], join_defaults: [], relationship: :child,
cardinality: :many, unique: false, ordered: false, preload_order: []]
@impl true
def after_compile_validation(%{queryable: queryable, join_through: join_through}, env) do
compiled = Ecto.Association.ensure_compiled(queryable, env)
join_compiled = Ecto.Association.ensure_compiled(join_through, env)
cond do
compiled == :skip ->
:ok
compiled == :not_found ->
{:error, "associated schema #{inspect queryable} does not exist"}
not function_exported?(queryable, :__schema__, 2) ->
{:error, "associated module #{inspect queryable} is not an Ecto schema"}
join_compiled == :skip ->
:ok
join_compiled == :not_found ->
{:error, ":join_through schema #{inspect join_through} does not exist"}
not function_exported?(join_through, :__schema__, 2) ->
{:error, ":join_through module #{inspect join_through} is not an Ecto schema"}
true ->
:ok
end
end
@impl true
def struct(module, name, opts) do
queryable = Keyword.fetch!(opts, :queryable)
related = Ecto.Association.related_from_query(queryable, name)
join_keys = opts[:join_keys]
join_through = opts[:join_through]
validate_join_through(name, join_through)
{owner_key, join_keys} =
case join_keys do
[{join_owner_key, owner_key}, {join_related_key, related_key}]
when is_atom(join_owner_key) and is_atom(owner_key) and
is_atom(join_related_key) and is_atom(related_key) ->
{owner_key, join_keys}
nil ->
{:id, default_join_keys(module, related)}
_ ->
raise ArgumentError,
"many_to_many #{inspect name} expect :join_keys to be a keyword list " <>
"with two entries, the first being how the join table should reach " <>
"the current schema and the second how the join table should reach " <>
"the associated schema. For example: #{inspect default_join_keys(module, related)}"
end
unless Module.get_attribute(module, :ecto_fields)[owner_key] do
raise ArgumentError, "schema does not have the field #{inspect owner_key} used by " <>
"association #{inspect name}, please set the :join_keys option accordingly"
end
on_delete = Keyword.get(opts, :on_delete, :nothing)
on_replace = Keyword.get(opts, :on_replace, :raise)
unless on_delete in @on_delete_opts do
raise ArgumentError, "invalid :on_delete option for #{inspect name}. " <>
"The only valid options are: " <>
Enum.map_join(@on_delete_opts, ", ", &"`#{inspect &1}`")
end
unless on_replace in @on_replace_opts do
raise ArgumentError, "invalid `:on_replace` option for #{inspect name}. " <>
"The only valid options are: " <>
Enum.map_join(@on_replace_opts, ", ", &"`#{inspect &1}`")
end
where = opts[:where] || []
join_where = opts[:join_where] || []
defaults = Ecto.Association.validate_defaults!(module, name, opts[:defaults] || [])
join_defaults = Ecto.Association.validate_defaults!(module, name, opts[:join_defaults] || [])
preload_order = Ecto.Association.validate_preload_order!(name, opts[:preload_order] || [])
unless is_list(where) do
raise ArgumentError, "expected `:where` for #{inspect name} to be a keyword list, got: `#{inspect where}`"
end
unless is_list(join_where) do
raise ArgumentError, "expected `:join_where` for #{inspect name} to be a keyword list, got: `#{inspect join_where}`"
end
if opts[:join_defaults] && is_binary(join_through) do
raise ArgumentError, ":join_defaults has no effect for a :join_through without a schema"
end
%__MODULE__{
field: name,
cardinality: Keyword.fetch!(opts, :cardinality),
owner: module,
related: related,
owner_key: owner_key,
join_keys: join_keys,
join_where: join_where,
join_through: join_through,
join_defaults: join_defaults,
queryable: queryable,
on_delete: on_delete,
on_replace: on_replace,
unique: Keyword.get(opts, :unique, false),
defaults: defaults,
where: where,
preload_order: preload_order
}
end
defp default_join_keys(module, related) do
[{Ecto.Association.association_key(module, :id), :id},
{Ecto.Association.association_key(related, :id), :id}]
end
@impl true
def joins_query(%{owner: owner, queryable: queryable,
join_through: join_through, join_keys: join_keys} = assoc) do
[{join_owner_key, owner_key}, {join_related_key, related_key}] = join_keys
from(o in owner,
join: j in ^join_through, on: field(j, ^join_owner_key) == field(o, ^owner_key),
join: q in ^queryable, on: field(j, ^join_related_key) == field(q, ^related_key))
|> Ecto.Association.combine_joins_query(assoc.where, 2)
|> Ecto.Association.combine_joins_query(assoc.join_where, 1)
end
def assoc_query(%{queryable: queryable} = refl, values) do
assoc_query(refl, queryable, values)
end
@impl true
def assoc_query(assoc, query, values) do
%{queryable: queryable, join_through: join_through, join_keys: join_keys, owner: owner} = assoc
[{join_owner_key, owner_key}, {join_related_key, related_key}] = join_keys
owner_key_type = owner.__schema__(:type, owner_key)
# We only need to join in the "join table". Preload and Ecto.assoc expressions can then filter
# by &1.join_owner_key in ^... to filter down to the associated entries in the related table.
query =
from(q in (query || queryable),
join: j in ^join_through, on: field(q, ^related_key) == field(j, ^join_related_key),
where: field(j, ^join_owner_key) in type(^values, {:in, ^owner_key_type})
)
|> Ecto.Association.combine_assoc_query(assoc.where)
Ecto.Association.combine_joins_query(query, assoc.join_where, length(query.joins))
end
@impl true
def build(refl, owner, attributes) do
refl
|> build(owner)
|> struct(attributes)
end
@impl true
def preload_info(%{join_keys: [{join_owner_key, owner_key}, {_, _}], owner: owner} = refl) do
owner_key_type = owner.__schema__(:type, owner_key)
# When preloading use the last bound table (which is the join table) and the join_owner_key
# to filter out related entities to the owner structs we're preloading with.
{:assoc, refl, {-1, join_owner_key, owner_key_type}}
end
@impl true
def on_repo_change(%{on_replace: :delete} = refl, parent_changeset,
%{action: :replace} = changeset, adapter, opts) do
on_repo_change(refl, parent_changeset, %{changeset | action: :delete}, adapter, opts)
end
def on_repo_change(%{join_keys: join_keys, join_through: join_through, join_where: join_where},
%{repo: repo, data: owner}, %{action: :delete, data: related}, adapter, opts) do
[{join_owner_key, owner_key}, {join_related_key, related_key}] = join_keys
owner_value = dump! :delete, join_through, owner, owner_key, adapter
related_value = dump! :delete, join_through, related, related_key, adapter
query =
join_through
|> where([j], field(j, ^join_owner_key) == ^owner_value)
|> where([j], field(j, ^join_related_key) == ^related_value)
|> Ecto.Association.combine_assoc_query(join_where)
query = %{query | prefix: owner.__meta__.prefix}
repo.delete_all(query, opts)
{:ok, nil}
end
def on_repo_change(%{field: field, join_through: join_through, join_keys: join_keys} = refl,
%{repo: repo, data: owner} = parent_changeset,
%{action: action} = changeset, adapter, opts) do
changeset = Ecto.Association.update_parent_prefix(changeset, owner)
case apply(repo, action, [changeset, opts]) do
{:ok, related} ->
[{join_owner_key, owner_key}, {join_related_key, related_key}] = join_keys
if insert_join?(parent_changeset, changeset, field, related_key) do
owner_value = dump! :insert, join_through, owner, owner_key, adapter
related_value = dump! :insert, join_through, related, related_key, adapter
data = %{join_owner_key => owner_value, join_related_key => related_value}
case insert_join(join_through, refl, parent_changeset, data, opts) do
{:error, join_changeset} ->
{:error, %{changeset | errors: join_changeset.errors ++ changeset.errors,
valid?: join_changeset.valid? and changeset.valid?}}
_ ->
{:ok, related}
end
else
{:ok, related}
end
{:error, changeset} ->
{:error, changeset}
end
end
defp validate_join_through(name, nil) do
raise ArgumentError, "many_to_many #{inspect name} associations require the :join_through option to be given"
end
defp validate_join_through(_, join_through) when is_atom(join_through) or is_binary(join_through) do
:ok
end
defp validate_join_through(name, _join_through) do
raise ArgumentError,
"many_to_many #{inspect name} associations require the :join_through option to be " <>
"an atom (representing a schema) or a string (representing a table)"
end
defp insert_join?(%{action: :insert}, _, _field, _related_key), do: true
defp insert_join?(_, %{action: :insert}, _field, _related_key), do: true
defp insert_join?(%{data: owner}, %{data: related}, field, related_key) do
current_key = Map.fetch!(related, related_key)
not Enum.any? Map.fetch!(owner, field), fn child ->
Map.get(child, related_key) == current_key
end
end
defp insert_join(join_through, _refl, %{repo: repo, data: owner}, data, opts) when is_binary(join_through) do
opts = Keyword.put_new(opts, :prefix, owner.__meta__.prefix)
repo.insert_all(join_through, [data], opts)
end
defp insert_join(join_through, refl, parent_changeset, data, opts) when is_atom(join_through) do
%{repo: repo, constraints: constraints, data: owner} = parent_changeset
changeset =
join_through
|> Ecto.Association.apply_defaults(refl.join_defaults, owner)
|> Map.merge(data)
|> Ecto.Changeset.change()
|> Map.put(:constraints, constraints)
|> put_new_prefix(owner.__meta__.prefix)
repo.insert(changeset, opts)
end
defp put_new_prefix(%{data: %{__meta__: %{prefix: prefix}}} = changeset, prefix),
do: changeset
defp put_new_prefix(%{data: %{__meta__: %{prefix: nil}}} = changeset, prefix),
do: update_in(changeset.data, &Ecto.put_meta(&1, prefix: prefix))
defp put_new_prefix(changeset, _),
do: changeset
defp field!(op, struct, field) do
Map.get(struct, field) || raise "could not #{op} join entry because `#{field}` is nil in #{inspect struct}"
end
defp dump!(action, join_through, struct, field, adapter) when is_binary(join_through) do
value = field!(action, struct, field)
type = struct.__struct__.__schema__(:type, field)
case Ecto.Type.adapter_dump(adapter, type, value) do
{:ok, value} ->
value
:error ->
raise Ecto.ChangeError,
"value `#{inspect value}` for `#{inspect struct.__struct__}.#{field}` " <>
"in `#{action}` does not match type #{inspect type}"
end
end
defp dump!(action, join_through, struct, field, _) when is_atom(join_through) do
field!(action, struct, field)
end
## Relation callbacks
@behaviour Ecto.Changeset.Relation
@impl true
def build(%{related: related, queryable: queryable, defaults: defaults}, owner) do
related
|> Ecto.Association.apply_defaults(defaults, owner)
|> Ecto.Association.merge_source(queryable)
end
## On delete callbacks
@doc false
def delete_all(refl, parent, repo_name, opts) do
%{join_through: join_through, join_keys: join_keys, owner: owner} = refl
[{join_owner_key, owner_key}, {_, _}] = join_keys
if value = Map.get(parent, owner_key) do
owner_type = owner.__schema__(:type, owner_key)
query = from j in join_through, where: field(j, ^join_owner_key) == type(^value, ^owner_type)
Ecto.Repo.Queryable.delete_all repo_name, query, opts
end
end
end
