Add the rdf_entity_graph config entity.

config/install/rdf_entity.graph.default.yml

@@ -0,0 +1,5 @@
+langcode: en
+status: true
+id: default
+name: Default
+description: 'Default graph. This is available for all entity types and bundles.'

config/schema/rdf_entity.schema.yml

@@ -74,6 +74,15 @@ rdf_entity.mapping.*:
   type: config_entity
   label: 'Stores the mapping between Drupal bundle settings and RDF representation'
   mapping:
+    id:
+      type: string
+      label: ID
+    entity_type_id:
+      type: string
+      label: 'Referred entity type'
+    bundle:
+      type: string
+      label: 'Referred bundle'
     rdf_type:
       type: string
       label: 'RDF type mapping'
@@ -84,7 +93,7 @@ rdf_entity.mapping.*:
         label: 'The mapping of a graph definition to a graph URI.'
     base_fields_mapping:
       type: sequence
-      label: 'Property'
+      label: 'The base fields mapping'
       sequence:
         type: sequence
         label: 'Column'

src/Entity/RdfEntityGraph.php

@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\rdf_entity\Entity;
+
+use Drupal\Core\Config\Entity\ConfigEntityBase;
+use Drupal\Core\Entity\Annotation\ConfigEntityType;
+
+/**
+ * Defines the RDF entity graph config entity.
+ *
+ * Used to store basic information about each RDF entity graph.
+ *
+ * @ConfigEntityType(
+ *   id = "rdf_entity_graph",
+ *   label = @Translation("RDF Graph"),
+ *   config_prefix = "graph",
+ *   entity_keys = {
+ *     "id" = "id",
+ *     "label" = "name",
+ *     "status" = "status"
+ *   },
+ *   config_export = {
+ *     "id",
+ *     "name",
+ *     "description",
+ *   },
+ * )
+ */
+class RdfEntityGraph extends ConfigEntityBase {
+
+  /**
+   * Default graph.
+   *
+   * @var string
+   */
+  const DEFAULT = 'default';
+
+  /**
+   * The unique ID of this RDF entity graph.
+   *
+   * @var string
+   */
+  protected $id;
+
+  /**
+   * The label of the RDF entity graph.
+   *
+   * @var string
+   */
+  protected $name;
+
+  /**
+   * The description of the RDF entity graph.
+   *
+   * @var string
+   */
+  protected $description;
+
+}