- Fix bug in naming convention feature where using a check

constraint convention that includes ``constraint_name`` would
then force all :class:`.Boolean` and :class:`.Enum` types to
require names as well, as these implicitly create a
constraint, even if the ultimate target backend were one that does
not require generation of the constraint such as Postgresql.
The mechanics of naming conventions for these particular
constraints has been reorganized such that the naming
determination is done at DDL compile time, rather than at
constraint/table construction time.
fixes #3067

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 7a8b07f8f..99b74b3c8 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -2902,7 +2902,13 @@ class IdentifierPreparer(object):
     def format_savepoint(self, savepoint, name=None):
         return self.quote(name or savepoint.ident)
 
-    def format_constraint(self, constraint):
+    @util.dependencies("sqlalchemy.sql.naming")
+    def format_constraint(self, naming, constraint):
+        if isinstance(constraint.name, elements._defer_name):
+            name = naming._constraint_name_for_table(
+                                        constraint, constraint.table)
+            if name:
+                return self.quote(name)
         return self.quote(constraint.name)
 
     def format_table(self, table, use_schema=True, name=None):