Remove unique constraint on attachment name

issue7613
review50531002

CHANGELOG

@@ -1,3 +1,4 @@
+* Remove unique constraint on attachment name
 * New icons
 * Add pyson TimeDelta
 * Remove button if it is not allowed to access some of its dependant fields

trytond/ir/attachment.py

@@ -3,7 +3,7 @@
 from sql import Null
 from sql.operators import Concat
 
-from ..model import ModelView, ModelSQL, fields, Unique
+from ..model import ModelView, ModelSQL, fields
 from ..transaction import Transaction
 from ..pyson import Eval
 from .resource import ResourceMixin
@@ -51,16 +51,6 @@ class Attachment(ResourceMixin, ModelSQL, ModelView):
                 'invisible': Eval('type') != 'data',
                 }, depends=['type']), 'get_size')
 
-    @classmethod
-    def __setup__(cls):
-        super(Attachment, cls).__setup__()
-        table = cls.__table__()
-        cls._sql_constraints += [
-            ('resource_name',
-                Unique(table, table.resource, table.name),
-                'The names of attachments must be unique by resource.'),
-        ]
-
     @classmethod
     def __register__(cls, module_name):
         cursor = Transaction().connection.cursor()
@@ -86,6 +76,9 @@ class Attachment(ResourceMixin, ModelSQL, ModelView):
             table.drop_column('digest')
             table.drop_column('collision')
 
+        # Migration from 4.8: remove unique constraint
+        table.drop_constraint('resource_name')
+
     @staticmethod
     def default_type():
         return 'data'