improvement: allow specifying multi-column foreign keys (#180)

* improvement: add match_with option on references
* improvement: add match_type option on references

Author: rbino

.formatter.exs

@@ -15,6 +15,8 @@ spark_locals_without_parens = [
   include: 1,
   index: 1,
   index: 2,
+  match_type: 1,
+  match_with: 1,
   message: 1,
   migrate?: 1,
   migration_defaults: 1,

documentation/dsls/DSL:-AshPostgres.DataLayer.cheatmd

@@ -1170,6 +1170,46 @@ reference :post, on_delete: :delete, on_update: :update, name: "comments_to_post
   </td>
 </tr>
 
+<tr>
+  <td style="text-align: left">
+    <a id="postgres-references-reference-match_with" href="#postgres-references-reference-match_with">
+      <span style="font-family: Inconsolata, Menlo, Courier, monospace;">
+        match_with
+      </span>
+    </a>
+      
+  </td>
+  <td style="text-align: left">
+    <code class="inline">Keyword.t</code>
+  </td>
+  <td style="text-align: left">
+    
+  </td>
+  <td style="text-align: left" colspan=2>
+    Defines additional keys to the foreign key in order to build a composite foreign key. The key should be the name of the source attribute (in the current resource), the value the name of the destination attribute.
+  </td>
+</tr>
+
+<tr>
+  <td style="text-align: left">
+    <a id="postgres-references-reference-match_type" href="#postgres-references-reference-match_type">
+      <span style="font-family: Inconsolata, Menlo, Courier, monospace;">
+        match_type
+      </span>
+    </a>
+      
+  </td>
+  <td style="text-align: left">
+    <code class="inline">:simple | :partial | :full</code>
+  </td>
+  <td style="text-align: left">
+    
+  </td>
+  <td style="text-align: left" colspan=2>
+    select if the match is `:simple`, `:partial`, or `:full`
+  </td>
+</tr>
+
   </tbody>
 </table>
 

lib/data_layer.ex

@@ -392,7 +392,8 @@ defmodule AshPostgres.DataLayer do
     transformers: [
       AshPostgres.Transformers.ValidateReferences,
       AshPostgres.Transformers.EnsureTableOrPolymorphic,
-      AshPostgres.Transformers.PreventMultidimensionalArrayAggregates
+      AshPostgres.Transformers.PreventMultidimensionalArrayAggregates,
+      AshPostgres.Transformers.PreventAttributeMultitenancyAndNonFullMatchType
     ]
 
   def migrate(args) do

lib/migration_generator/migration_generator.ex

@@ -707,13 +707,18 @@ defmodule AshPostgres.MigrationGenerator do
           primary_key?: merge_uniq!(references, table, :primary_key?, name),
           on_delete: merge_uniq!(references, table, :on_delete, name),
           on_update: merge_uniq!(references, table, :on_update, name),
+          match_with: merge_uniq!(references, table, :match_with, name) |> to_map(),
+          match_type: merge_uniq!(references, table, :match_type, name),
           name: merge_uniq!(references, table, :name, name),
           table: merge_uniq!(references, table, :table, name),
           schema: merge_uniq!(references, table, :schema, name)
         }
     end
   end
 
+  defp to_map(nil), do: nil
+  defp to_map(kw_list) when is_list(kw_list), do: Map.new(kw_list)
+
   defp merge_uniq!(references, table, field, attribute) do
     references
     |> Enum.map(&Map.get(&1, field))
@@ -2675,6 +2680,8 @@ defmodule AshPostgres.MigrationGenerator do
             multitenancy: multitenancy(relationship.destination),
             on_delete: configured_reference.on_delete,
             on_update: configured_reference.on_update,
+            match_with: configured_reference.match_with,
+            match_type: configured_reference.match_type,
             name: configured_reference.name,
             primary_key?: destination_attribute.primary_key?,
             schema:
@@ -2700,6 +2707,8 @@ defmodule AshPostgres.MigrationGenerator do
       |> Kernel.||(%{
         on_delete: nil,
         on_update: nil,
+        match_with: nil,
+        match_type: nil,
         deferrable: false,
         schema:
           relationship.context[:data_layer][:schema] ||
@@ -3029,6 +3038,13 @@ defmodule AshPostgres.MigrationGenerator do
         |> Map.put_new(:on_update, nil)
         |> Map.update!(:on_delete, &(&1 && String.to_atom(&1)))
         |> Map.update!(:on_update, &(&1 && String.to_atom(&1)))
+        |> Map.put_new(:match_with, nil)
+        |> Map.put_new(:match_type, nil)
+        |> Map.update!(
+          :match_with,
+          &(&1 && Enum.into(&1, %{}, fn {k, v} -> {String.to_atom(k), String.to_atom(v)} end))
+        )
+        |> Map.update!(:match_type, &(&1 && String.to_atom(&1)))
         |> Map.put(
           :name,
           Map.get(references, :name) || "#{table}_#{attribute.source}_fkey"

lib/migration_generator/operation.ex

@@ -66,6 +66,53 @@ defmodule AshPostgres.MigrationGenerator.Operation do
     def reference_type(%{type: type}, _) do
       type
     end
+
+    def with_match(reference, source_attribute \\ nil)
+
+    def with_match(
+          %{
+            primary_key?: false,
+            destination_attribute: reference_attribute,
+            multitenancy: %{strategy: :attribute, attribute: destination_attribute}
+          } = reference,
+          source_attribute
+        )
+        when not is_nil(source_attribute) and reference_attribute != destination_attribute do
+      with_targets =
+        [{as_atom(source_attribute), as_atom(destination_attribute)}]
+        |> Enum.into(reference.match_with || %{})
+        |> with_targets()
+
+      # We can only have match: :full here, this gets validated by a Transformer
+      join([with_targets, "match: :full"])
+    end
+
+    def with_match(reference, _) do
+      with_targets = with_targets(reference.match_with)
+      match_type = match_type(reference.match_type)
+
+      if with_targets != nil or match_type != nil do
+        join([with_targets, match_type])
+      else
+        nil
+      end
+    end
+
+    def with_targets(targets) when is_map(targets) do
+      targets_string =
+        targets
+        |> Enum.map_join(", ", fn {source, destination} -> "#{source}: :#{destination}" end)
+
+      "with: [#{targets_string}]"
+    end
+
+    def with_targets(_), do: nil
+
+    def match_type(type) when type in [:simple, :partial, :full] do
+      "match: :#{type}"
+    end
+
+    def match_type(_), do: nil
   end
 
   defmodule CreateTable do
@@ -88,14 +135,11 @@ defmodule AshPostgres.MigrationGenerator.Operation do
                   table: table,
                   destination_attribute: reference_attribute,
                   schema: destination_schema,
-                  multitenancy: %{strategy: :attribute, attribute: destination_attribute}
+                  multitenancy: %{strategy: :attribute}
                 } = reference
             } = attribute
         }) do
-      with_match =
-        if !reference.primary_key? && destination_attribute != reference_attribute do
-          "with: [#{as_atom(source_attribute)}: :#{as_atom(destination_attribute)}], match: :full"
-        end
+      with_match = with_match(reference, source_attribute)
 
       size =
         if attribute[:size] do
@@ -136,6 +180,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
                 } = reference
             } = attribute
         }) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
@@ -146,6 +192,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
         "references(:#{as_atom(table)}",
         [
           "column: #{inspect(destination_attribute)}",
+          with_match,
           option("prefix", destination_schema),
           "name: #{inspect(reference.name)}",
           "type: #{inspect(reference_type(attribute, reference))}",
@@ -198,6 +245,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
                 } = reference
             } = attribute
         }) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
@@ -208,6 +257,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
         "references(:#{as_atom(table)}",
         [
           "column: #{inspect(destination_attribute)}",
+          with_match,
           "name: #{inspect(reference.name)}",
           "type: #{inspect(reference_type(attribute, reference))}",
           "prefix: prefix()",
@@ -236,6 +286,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
                 } = reference
             } = attribute
         }) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
@@ -251,6 +303,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
         "references(:#{as_atom(table)}",
         [
           "column: #{inspect(destination_attribute)}",
+          with_match,
           "name: #{inspect(reference.name)}",
           "type: #{inspect(reference_type(attribute, reference))}",
           option("prefix", destination_schema),
@@ -277,6 +330,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
                 } = reference
             } = attribute
         }) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
@@ -287,6 +342,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
         "references(:#{as_atom(table)}",
         [
           "column: #{inspect(destination_attribute)}",
+          with_match,
           "name: #{inspect(reference.name)}",
           "type: #{inspect(reference_type(attribute, reference))}",
           option("prefix", destination_schema),
@@ -449,13 +505,16 @@ defmodule AshPostgres.MigrationGenerator.Operation do
            } = attribute,
            _schema
          ) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
         end
 
       join([
         "references(:#{as_atom(table)}, column: #{inspect(destination_attribute)}",
+        with_match,
         "name: #{inspect(reference.name)}",
         "type: #{inspect(reference_type(attribute, reference))}",
         size,
@@ -471,7 +530,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
            %{
              references:
                %{
-                 multitenancy: %{strategy: :attribute, attribute: destination_attribute},
+                 multitenancy: %{strategy: :attribute},
                  table: table,
                  schema: destination_schema,
                  destination_attribute: reference_attribute
@@ -484,10 +543,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
           destination_schema
         end
 
-      with_match =
-        if !reference.primary_key? && destination_attribute != reference_attribute do
-          "with: [#{as_atom(source_attribute)}: :#{as_atom(destination_attribute)}], match: :full"
-        end
+      with_match = with_match(reference, source_attribute)
 
       size =
         if attribute[:size] do
@@ -519,6 +575,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
            } = attribute,
            schema
          ) do
+      with_match = with_match(reference)
+
       size =
         if attribute[:size] do
           "size: #{attribute[:size]}"
@@ -531,6 +589,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
 
       join([
         "references(:#{as_atom(table)}, column: #{inspect(destination_attribute)}",
+        with_match,
         "name: #{inspect(reference.name)}",
         "type: #{inspect(reference_type(attribute, reference))}",
         size,
@@ -553,6 +612,8 @@ defmodule AshPostgres.MigrationGenerator.Operation do
            } = attribute,
            schema
          ) do
+      with_match = with_match(reference)
+
       destination_schema =
         if schema != destination_schema do
           destination_schema
@@ -565,6 +626,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
 
       join([
         "references(:#{as_atom(table)}, column: #{inspect(destination_attribute)}",
+        with_match,
         "name: #{inspect(reference.name)}",
         "type: #{inspect(reference_type(attribute, reference))}",
         size,

lib/reference.ex

@@ -1,6 +1,15 @@
 defmodule AshPostgres.Reference do
   @moduledoc "Represents the configuration of a reference (i.e foreign key)."
-  defstruct [:relationship, :on_delete, :on_update, :name, :deferrable, ignore?: false]
+  defstruct [
+    :relationship,
+    :on_delete,
+    :on_update,
+    :name,
+    :match_with,
+    :match_type,
+    :deferrable,
+    ignore?: false
+  ]
 
   def schema do
     [
@@ -37,6 +46,15 @@ defmodule AshPostgres.Reference do
         type: :string,
         doc:
           "The name of the foreign key to generate in the database. Defaults to <table>_<source_attribute>_fkey"
+      ],
+      match_with: [
+        type: :non_empty_keyword_list,
+        doc:
+          "Defines additional keys to the foreign key in order to build a composite foreign key. The key should be the name of the source attribute (in the current resource), the value the name of the destination attribute."
+      ],
+      match_type: [
+        type: {:one_of, [:simple, :partial, :full]},
+        doc: "select if the match is `:simple`, `:partial`, or `:full`"
       ]
     ]
   end