Add support for ON DELETE SET DEFAULT

integration_test/myxql/test_helper.exs

@@ -116,8 +116,11 @@ excludes = [
   :map_boolean_in_expression,
   # MySQL doesn't support indexed parameters
   :placeholders,
-  # MySQL doesn't support specifying columns for ON DELETE SET NULL
+  # MySQL doesn't support ON DELETE SET DEFAULT
+  :on_delete_default_all,
+  # MySQL doesn't support specifying columns for ON DELETE SET NULL or ON DELETE SET DEFAULT
   :on_delete_nilify_column_list,
+  :on_delete_default_column_list,
   # MySQL doesnt' support anything except a single column in DISTINCT
   :multicolumn_distinct,
   # uncertain whether we can support this. needs more exploring

integration_test/pg/test_helper.exs

@@ -115,7 +115,7 @@ excludes = [:selected_as_with_having, :selected_as_with_order_by_expression]
 excludes_above_9_5 = [:without_conflict_target]
 excludes_below_9_6 = [:add_column_if_not_exists, :no_error_on_conditional_column_migration]
 excludes_below_12_0 = [:plan_cache_mode]
-excludes_below_15_0 = [:on_delete_nilify_column_list]
+excludes_below_15_0 = [:on_delete_nilify_column_list, :on_delete_default_column_list]
 
 exclude_list = excludes ++ excludes_above_9_5
 

integration_test/sql/migration.exs

@@ -254,6 +254,64 @@ defmodule Ecto.Integration.MigrationTest do
     end
   end
 
+  defmodule OnDeleteDefaultAllMigration do
+    use Ecto.Migration
+
+    def up do
+      create table(:parent, primary_key: [type: :bigint]) do
+        add :col1, :integer
+        add :col2, :integer
+      end
+
+      create unique_index(:parent, [:id, :col1, :col2])
+
+      create table(:ref) do
+        add :col1, :integer, default: 2
+        add :col2, :integer, default: 3
+
+        add :parent_id,
+            references(:parent,
+              with: [col1: :col1, col2: :col2],
+              on_delete: :default_all
+            ), default: 1
+      end
+    end
+
+    def down do
+      drop table(:ref)
+      drop table(:parent)
+    end
+  end
+
+  defmodule OnDeleteDefaultColumnsMigration do
+    use Ecto.Migration
+
+    def up do
+      create table(:parent, primary_key: [type: :bigint]) do
+        add :col1, :integer
+        add :col2, :integer
+      end
+
+      create unique_index(:parent, [:id, :col1, :col2])
+
+      create table(:ref) do
+        add :col1, :integer, default: 2
+        add :col2, :integer, default: 3
+
+        add :parent_id,
+            references(:parent,
+              with: [col1: :col1, col2: :col2],
+              on_delete: {:default, [:parent_id, :col2]}
+            ), default: 1
+      end
+    end
+
+    def down do
+      drop table(:ref)
+      drop table(:parent)
+    end
+  end
+
   defmodule CompositeForeignKeyMigration do
     use Ecto.Migration
 
@@ -683,4 +741,35 @@ defmodule Ecto.Integration.MigrationTest do
 
     :ok = down(PoolRepo, num, OnDeleteNilifyColumnsMigration, log: false)
   end
+
+  @tag :on_delete_default_all
+  test "default all on_delete constraint", %{migration_number: num} do
+    assert :ok == up(PoolRepo, num, OnDeleteDefaultAllMigration, log: false)
+
+    PoolRepo.insert_all("parent", [%{id: 1, col1: 2, col2: 3}])
+    {id, col1, col2} = {Enum.random(10..1000), Enum.random(10..1000), Enum.random(10..1000)}
+
+    PoolRepo.insert_all("parent", [%{id: id, col1: col1, col2: col2}])
+    PoolRepo.insert_all("ref", [%{parent_id: id, col1: col1, col2: col2}])
+    PoolRepo.delete_all(from p in "parent", where: p.id == ^id)
+    assert [{1, 2, 3}] == PoolRepo.all from r in "ref", select: {r.parent_id, r.col1, r.col2}
+
+    :ok = down(PoolRepo, num, OnDeleteDefaultAllMigration, log: false)
+  end
+
+  @tag :on_delete_default_column_list
+  test "default list of columns on_delete constraint", %{migration_number: num} do
+    assert :ok == up(PoolRepo, num, OnDeleteDefaultColumnsMigration, log: false)
+
+    PoolRepo.insert_all("parent", [%{id: 1, col1: 20, col2: 3}])
+
+    {id, col2} = {Enum.random(10..1000), Enum.random(10..1000)}
+
+    PoolRepo.insert_all("parent", [%{id: id, col1: 20, col2: col2}])
+    PoolRepo.insert_all("ref", [%{parent_id: id, col1: 20, col2: col2}])
+    PoolRepo.delete_all(from p in "parent", where: p.id == ^id)
+    assert [{1, 20, 3}] == PoolRepo.all from r in "ref", select: {r.parent_id, r.col1, r.col2}
+
+    :ok = down(PoolRepo, num, OnDeleteDefaultColumnsMigration, log: false)
+  end
 end

integration_test/tds/test_helper.exs

@@ -57,8 +57,9 @@ ExUnit.start(
     :selected_as_with_having,
     # MSSQL can't reference aliased columns in ORDER BY expressions
     :selected_as_with_order_by_expression,
-    # MSSQL doesn't support specifying columns for ON DELETE SET NULL
+    # MSSQL doesn't support specifying columns for ON DELETE SET NULL or ON DELETE SET DEFAULT
     :on_delete_nilify_column_list,
+    :on_delete_default_column_list,
     # MSSQL doesnt' support anything except a single column in DISTINCT
     :multicolumn_distinct,
     # MSSQL doesnt' support subqueries in group by or in distinct

lib/ecto/adapters/myxql/connection.ex

@@ -1484,6 +1484,20 @@ if Code.ensure_loaded?(MyXQL) do
       )
     end
 
+    defp reference_on_delete(:default_all) do
+      error!(
+        nil,
+        "MySQL adapter does not support the `:default_all` action for `:on_delete`"
+      )
+    end
+
+    defp reference_on_delete({:default, _columns}) do
+      error!(
+        nil,
+        "MySQL adapter does not support the `{:default, columns}` action for `:on_delete`"
+      )
+    end
+
     defp reference_on_delete(:delete_all), do: " ON DELETE CASCADE"
     defp reference_on_delete(:restrict), do: " ON DELETE RESTRICT"
     defp reference_on_delete(_), do: []

lib/ecto/adapters/postgres/connection.ex

@@ -1912,6 +1912,11 @@ if Code.ensure_loaded?(Postgrex) do
     defp reference_on_delete({:nilify, columns}),
       do: [" ON DELETE SET NULL (", quote_names(columns), ")"]
 
+    defp reference_on_delete(:default_all), do: " ON DELETE SET DEFAULT"
+
+    defp reference_on_delete({:default, columns}),
+      do: [" ON DELETE SET DEFAULT (", quote_names(columns), ")"]
+
     defp reference_on_delete(:delete_all), do: " ON DELETE CASCADE"
     defp reference_on_delete(:restrict), do: " ON DELETE RESTRICT"
     defp reference_on_delete(_), do: []

lib/ecto/adapters/tds/connection.ex

@@ -1674,6 +1674,15 @@ if Code.ensure_loaded?(Tds) do
       error!(nil, "Tds adapter does not support the `{:nilify, columns}` action for `:on_delete`")
     end
 
+    defp reference_on_delete(:default_all), do: " ON DELETE SET DEFAULT"
+
+    defp reference_on_delete({:default, _columns}) do
+      error!(
+        nil,
+        "Tds adapter does not support the `{:default, columns}` action for `:on_delete`"
+      )
+    end
+
     defp reference_on_delete(:delete_all), do: " ON DELETE CASCADE"
     defp reference_on_delete(:nothing), do: " ON DELETE NO ACTION"
     defp reference_on_delete(_), do: []

lib/ecto/migration.ex

@@ -1515,8 +1515,8 @@ defmodule Ecto.Migration do
       the example above), or `nil`.
     * `:type` - The foreign key type, which defaults to `:bigserial`.
     * `:on_delete` - What to do if the referenced entry is deleted. May be
-      `:nothing` (default), `:delete_all`, `:nilify_all`, `{:nilify, columns}`,
-      or `:restrict`. `{:nilify, columns}` expects a list of atoms for `columns`
+      `:nothing` (default), `:delete_all`, `:nilify_all`, `{:nilify, columns}`, `:default_all`, `{:default, columns}`
+      or `:restrict`. `{:nilify, columns}` and `{:default, columns}` expect a list of atoms for `columns`
       and is not supported by all databases.
     * `:on_update` - What to do if the referenced entry is updated. May be
       `:nothing` (default), `:update_all`, `:nilify_all`, or `:restrict`.
@@ -1561,13 +1561,14 @@ defmodule Ecto.Migration do
   end
 
   defp check_on_delete!(on_delete)
-       when on_delete in [:nothing, :delete_all, :nilify_all, :restrict],
+       when on_delete in [:nothing, :delete_all, :nilify_all, :default_all, :restrict],
        do: :ok
 
-  defp check_on_delete!({:nilify, columns}) when is_list(columns) do
+  defp check_on_delete!({option, columns})
+       when option in [:nilify, :default] and is_list(columns) do
     unless Enum.all?(columns, &is_atom/1) do
       raise ArgumentError,
-            "expected `columns` in `{:nilify, columns}` to be a list of atoms, got: #{inspect(columns)}"
+            "expected `columns` in `{#{inspect(option)}, columns}` to be a list of atoms, got: #{inspect(columns)}"
     end
 
     :ok

test/ecto/adapters/myxql_test.exs

@@ -1781,6 +1781,25 @@ defmodule Ecto.Adapters.MyXQLTest do
 
     msg = "MySQL adapter does not support the `{:nilify, columns}` action for `:on_delete`"
     assert_raise ArgumentError, msg, fn -> execute_ddl(create) end
+
+    create =
+      {:create, table(:posts),
+       [
+         {:add, :category_1, %Reference{table: :categories, on_delete: :default_all}, []}
+       ]}
+
+    msg = "MySQL adapter does not support the `:default_all` action for `:on_delete`"
+    assert_raise ArgumentError, msg, fn -> execute_ddl(create) end
+
+    create =
+      {:create, table(:posts),
+       [
+         {:add, :category_1, %Reference{table: :categories, on_delete: {:default, [:category_1]}},
+          []}
+       ]}
+
+    msg = "MySQL adapter does not support the `{:default, columns}` action for `:on_delete`"
+    assert_raise ArgumentError, msg, fn -> execute_ddl(create) end
   end
 
   test "create table with options" do

test/ecto/adapters/postgres_test.exs

@@ -2231,6 +2231,13 @@ defmodule Ecto.Adapters.PostgresTest do
             table: :categories,
             with: [here: :there, here2: :there2],
             on_delete: {:nilify, [:here, :here2]}
+          }, []},
+         {:add, :category_15, %Reference{table: :categories, on_delete: :default_all}, []},
+         {:add, :category_16,
+          %Reference{
+            table: :categories,
+            with: [here: :there, here2: :there2],
+            on_delete: {:default, [:here, :here2]}
           }, []}
        ]}
 
@@ -2252,6 +2259,8 @@ defmodule Ecto.Adapters.PostgresTest do
              "category_12" bigint, CONSTRAINT "posts_category_12_fkey" FOREIGN KEY ("category_12","here") REFERENCES "categories"("id","there"),
              "category_13" bigint, CONSTRAINT "posts_category_13_fkey" FOREIGN KEY ("category_13","here") REFERENCES "categories"("id","there") MATCH FULL ON UPDATE RESTRICT,
              "category_14" bigint, CONSTRAINT "posts_category_14_fkey" FOREIGN KEY ("category_14","here","here2") REFERENCES "categories"("id","there","there2") ON DELETE SET NULL ("here","here2"),
+             "category_15" bigint, CONSTRAINT "posts_category_15_fkey" FOREIGN KEY ("category_15") REFERENCES "categories"("id") ON DELETE SET DEFAULT,
+             "category_16" bigint, CONSTRAINT "posts_category_16_fkey" FOREIGN KEY ("category_16","here","here2") REFERENCES "categories"("id","there","there2") ON DELETE SET DEFAULT ("here","here2"),
              PRIMARY KEY ("id"))
              """
              |> remove_newlines

test/ecto/adapters/tds_test.exs

@@ -1518,6 +1518,16 @@ defmodule Ecto.Adapters.TdsTest do
 
     msg = "Tds adapter does not support the `{:nilify, columns}` action for `:on_delete`"
     assert_raise ArgumentError, msg, fn -> execute_ddl(create) end
+
+    create =
+      {:create, table(:posts),
+       [
+         {:add, :category_1, %Reference{table: :categories, on_delete: {:default, [:category_1]}},
+          []}
+       ]}
+
+    msg = "Tds adapter does not support the `{:default, columns}` action for `:on_delete`"
+    assert_raise ArgumentError, msg, fn -> execute_ddl(create) end
   end
 
   test "create table with options" do