Add a reference field to get to the owner with 1 click.

base_multi_image/hooks.py

@@ -35,7 +35,12 @@ def pre_init_hook_for_submodules(cr, model, field):
         # fields.Binary(attachment=True), get the ir_attachment record ID
         else:
             extract_query = """
-                SELECT res_id, res_model, 'filestore', id
+                SELECT
+                    res_id,
+                    res_model,
+                    CONCAT_WS(',', res_model, res_id),
+                    'filestore',
+                    id
                 FROM ir_attachment
                 WHERE res_field='%(field)s' AND res_model='%(model)s'
             """ % {"model": model, "field": field}
@@ -45,6 +50,7 @@ def pre_init_hook_for_submodules(cr, model, field):
                 INSERT INTO base_multi_image_image (
                     owner_id,
                     owner_model,
+                    owner_ref_id,
                     storage,
                     %s
                 )

base_multi_image/models/image.py

@@ -27,6 +27,12 @@ class Image(models.Model):
         required=True)
     owner_model = fields.Char(
         required=True)
+    owner_ref_id = fields.Reference(
+        selection="_selection_owner_ref_id",
+        string="Referenced Owner",
+        compute="_compute_owner_ref_id",
+        store=True,
+    )
     storage = fields.Selection(
         [('url', 'URL'), ('file', 'OS file'), ('db', 'Database'),
          ('filestore', 'Filestore')],
@@ -74,6 +80,19 @@ class Image(models.Model):
     show_technical = fields.Boolean(
         compute="_show_technical")
 
+    @api.model
+    @tools.ormcache("self")
+    def _selection_owner_ref_id(self):
+        """Allow any model; after all, this field is readonly."""
+        return [(r.model, r.name) for r in self.env["ir.model"].search([])]
+
+    @api.multi
+    @api.depends("owner_model", "owner_id")
+    def _compute_owner_ref_id(self):
+        """Get a reference field based on the split model and id fields."""
+        for s in self:
+            s.owner_ref_id = "{0.owner_model},{0.owner_id}".format(s)
+
     @api.multi
     @api.depends('storage', 'path', 'file_db_store', 'url')
     def _get_image(self):

base_multi_image/views/image_view.xml

@@ -19,6 +19,7 @@
                         <field name="show_technical" invisible="True"/>
                         <field name="owner_model"/>
                         <field name="owner_id"/>
+                        <field name="owner_ref_id"/>
                         <field name="sequence"/>
                     </group>
                     <group string="Name">