Streamline visitors.iterate

This method might be used more significantly in the
ORM refactor, so further refine it.

* all get_children() methods now work entirely based on iterators.
  Basically only select() was sensitive to this anymore and it now
  chains the iterators together

* remove all kinds of flags like column_collections, schema_visitor
  that apparently aren't used anymore.

* remove the "depthfirst" visitors as these don't seem to be
  used either.

* make sure select() yields its columns first as these will be used
  to determine the current mapper.

Change-Id: I05273a2d5306a57c2d1b0979050748cf3ac964bf

1 files changed, 0 insertions, 29 deletions

diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index 08dc487d4..8d28d6309 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -117,10 +117,6 @@ class SchemaItem(SchemaEventTarget, visitors.Visitable):
                 else:
                     spwd(self)
 
-    def get_children(self, **kwargs):
-        """used to allow SchemaVisitor access"""
-        return []
-
     def __repr__(self):
         return util.generic_repr(self, omit_kwarg=["info"])
 
@@ -820,21 +816,6 @@ class Table(DialectKWArgs, SchemaItem, TableClause):
         metadata._add_table(self.name, self.schema, self)
         self.metadata = metadata
 
-    def get_children(
-        self, column_collections=True, schema_visitor=False, **kw
-    ):
-        # TODO: consider that we probably don't need column_collections=True
-        # at all, it does not seem to impact anything
-        if not schema_visitor:
-            return TableClause.get_children(
-                self, column_collections=column_collections, **kw
-            )
-        else:
-            if column_collections:
-                return list(self.columns)
-            else:
-                return []
-
     @util.deprecated(
         "1.4",
         "The :meth:`_schema.Table.exists` method is deprecated and will be "
@@ -1656,16 +1637,6 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause):
             selectable.foreign_keys.update(fk)
         return c.key, c
 
-    def get_children(self, schema_visitor=False, **kwargs):
-        if schema_visitor:
-            return (
-                [x for x in (self.default, self.onupdate) if x is not None]
-                + list(self.foreign_keys)
-                + list(self.constraints)
-            )
-        else:
-            return ColumnClause.get_children(self, **kwargs)
-
 
 class ForeignKey(DialectKWArgs, SchemaItem):
     """Defines a dependency between two columns.