make migrate.changeset.constraint.ForeignKeyConstraint.autoname work

with SQLAlchemy 0.5 and 0.6

1 files changed, 11 insertions, 3 deletions

diff --git a/migrate/changeset/constraint.py b/migrate/changeset/constraint.py
index 34b2d1a..476a456 100644
--- a/migrate/changeset/constraint.py
+++ b/migrate/changeset/constraint.py
@@ -126,9 +126,17 @@ class ForeignKeyConstraint(ConstraintChangeset, schema.ForeignKeyConstraint):
 
     def autoname(self):
         """Mimic the database's automatic constraint names"""
-        ret = "%(table)s_%(firstcolumn)s_fkey" % dict(
-            table=self.table.name,
-            firstcolumn=self.columns[0],)
+        if hasattr(self.columns, 'keys'):
+            # SA <= 0.5
+            firstcol = self.columns[self.columns.keys()[0]]
+            ret = "%(table)s_%(firstcolumn)s_fkey" % dict(
+                table=firstcol.table.name,
+                firstcolumn=firstcol.name,)
+        else:
+            # SA >= 0.6
+            ret = "%(table)s_%(firstcolumn)s_fkey" % dict(
+                table=self.table.name,
+                firstcolumn=self.columns[0],)
         return ret