--- a/cubicweb/entities/adapters.py	Wed Mar 13 10:21:39 2019 +0100
+++ b/cubicweb/entities/adapters.py	Mon Mar 11 17:43:23 2019 +0100
@@ -27,6 +27,7 @@
 
 from cubicweb import (Unauthorized, ValidationError, view, ViolatedConstraint,
                       UniqueTogetherError)
+from cubicweb.schema import constraint_name_for
 from cubicweb.predicates import is_instance, relation_possible, match_exception
 
 
@@ -474,7 +475,7 @@
         for rschema, attrschema in eschema.attribute_definitions():
             rdef = rschema.rdef(eschema, attrschema)
             for constraint in rdef.constraints:
-                if cstrname == constraint.name_for(rdef):
+                if cstrname == constraint_name_for(constraint, rdef):
                     break
             else:
                 continue

--- a/cubicweb/hooks/syncschema.py	Wed Mar 13 10:21:39 2019 +0100
+++ b/cubicweb/hooks/syncschema.py	Mon Mar 11 17:43:23 2019 +0100
@@ -37,6 +37,7 @@
 from cubicweb.predicates import is_instance
 from cubicweb.schema import (SCHEMA_TYPES, META_RTYPES, VIRTUAL_RTYPES,
                              CONSTRAINTS, UNIQUE_CONSTRAINTS, ETYPE_NAME_MAP)
+from cubicweb.schema import constraint_name_for
 from cubicweb.server import hook, schemaserial as ss, schema2sql as y2sql
 from cubicweb.server.sqlutils import SQL_PREFIX
 from cubicweb.hooks.synccomputed import RecomputeAttributeOperation
@@ -758,7 +759,7 @@
                           'IntervalBoundConstraint',
                           'StaticVocabularyConstraint'):
             cnx.system_sql('ALTER TABLE %s%s DROP CONSTRAINT %s'
-                           % (SQL_PREFIX, rdef.subject, self.oldcstr.name_for(rdef)))
+                           % (SQL_PREFIX, rdef.subject, constraint_name_for(self.oldcstr, rdef)))
 
     def revertprecommit_event(self):
         # revert changes on in memory schema
@@ -812,7 +813,7 @@
             # oldcstr is the new constraint when the attribute is being added in the same
             # transaction or when constraint value is updated. So we've to take care...
             if oldcstr is not None:
-                oldcstrname = self.oldcstr.name_for(rdef)
+                oldcstrname = constraint_name_for(self.oldcstr, rdef)
                 if oldcstrname != cstrname:
                     cnx.system_sql('ALTER TABLE %s%s DROP CONSTRAINT %s'
                                    % (SQL_PREFIX, rdef.subject, oldcstrname))

--- a/cubicweb/schema.py	Wed Mar 13 10:21:39 2019 +0100
+++ b/cubicweb/schema.py	Mon Mar 11 17:43:23 2019 +0100
@@ -1177,14 +1177,13 @@
 
 # additional cw specific constraints ###########################################
 
-@monkeypatch(BaseConstraint)
-def name_for(self, rdef):
+def constraint_name_for(constraint, rdef):
     """Return a unique, size controlled, name for this constraint applied to given `rdef`.
 
     This name may be used as name for the constraint in the database.
     """
-    return 'cstr' + md5((rdef.subject.type + rdef.rtype.type + self.type()
-                         + (self.serialize() or '')).encode('ascii')).hexdigest()
+    return 'cstr' + md5((rdef.subject.type + rdef.rtype.type + constraint.type()
+                         + (constraint.serialize() or '')).encode('ascii')).hexdigest()
 
 
 class BaseRQLConstraint(RRQLExpression, BaseConstraint):

--- a/cubicweb/server/schema2sql.py	Wed Mar 13 10:21:39 2019 +0100
+++ b/cubicweb/server/schema2sql.py	Mon Mar 11 17:43:23 2019 +0100
@@ -27,6 +27,8 @@
 from logilab import database
 from logilab.common.decorators import monkeypatch
 
+from cubicweb.schema import constraint_name_for
+
 # default are usually not handled at the sql level. If you want them, set
 # SET_DEFAULT to True
 SET_DEFAULT = False
@@ -187,7 +189,7 @@
     constraint. Maybe (None, None) if the constraint is not handled in the backend.
     """
     attr = rdef.rtype.type
-    cstrname = constraint.name_for(rdef)
+    cstrname = constraint_name_for(constraint, rdef)
     if constraint.type() == 'BoundaryConstraint':
         value = constraint_value_as_sql(constraint.boundary, dbhelper, prefix)
         return cstrname, '%s%s %s %s' % (prefix, attr, constraint.operator, value)

--- a/cubicweb/server/test/unittest_migractions.py	Wed Mar 13 10:21:39 2019 +0100
+++ b/cubicweb/server/test/unittest_migractions.py	Mon Mar 11 17:43:23 2019 +0100
@@ -31,6 +31,7 @@
                       ExecutionError, Binary)
 from cubicweb.devtools import startpgcluster, stoppgcluster
 from cubicweb.devtools.testlib import CubicWebTC, TemporaryDirectory
+from cubicweb.schema import constraint_name_for
 from cubicweb.server.sqlutils import SQL_PREFIX
 from cubicweb.server.migractions import ServerMigrationHelper
 from cubicweb.server.sources import storages
@@ -616,7 +617,7 @@
             self.assertEqual(len(constraints), 1, constraints)
             rdef = migrschema['promo'].rdefs['Personne', 'String']
             cstr = rdef.constraint_by_type('StaticVocabularyConstraint')
-            self.assertIn(cstr.name_for(rdef), constraints)
+            self.assertIn(constraint_name_for(cstr, rdef), constraints)
 
     def _erqlexpr_rset(self, cnx, action, ertype):
         rql = 'RQLExpression X WHERE ET is CWEType, ET %s_permission X, ET name %%(name)s' % action