Document Table/Column accessors

As Sphinx will not allow us to add attributes to the
.rst file while maintaining order, these have to be added
as class-level attributes.

Inlcude notes that "index" and "unique" parameters, while
indicated by Column.index / Column.unique, do not actually
indicate if the column is part of an index.

Fixes: #5851
Change-Id: I18fbaf6c504c4b1005b4c51057f80397fb48b387

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index a1dfa8b56..b4f6c8bc9 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -749,9 +749,17 @@ class FromClause(roles.AnonymizedFromClauseRole, Selectable):
 
     @util.memoized_property
     def foreign_keys(self):
-        """Return the collection of :class:`_schema.ForeignKey` objects
+        """Return the collection of :class:`_schema.ForeignKey` marker objects
         which this FromClause references.
 
+        Each :class:`_schema.ForeignKey` is a member of a
+        :class:`_schema.Table`-wide
+        :class:`_schema.ForeignKeyConstraint`.
+
+        .. seealso::
+
+            :attr:`_schema.Table.foreign_key_constraints`
+
         """
         self._init_collections()
         self._populate_column_collection()