From: Bob Halley <halley@dnspython.org>
Date: Sun, 28 Nov 2021 19:29:11 +0000 (-0800)
Subject: more doco for CNAME-and-other-data
X-Git-Tag: v2.2.0rc1~19^2~8
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fce73919a484d3a985e1acd5a099796cd9a563f2;p=thirdparty%2Fdnspython.git

more doco for CNAME-and-other-data
---

diff --git a/dns/node.py b/dns/node.py
index 261de37a..4a750eb0 100644
--- a/dns/node.py
+++ b/dns/node.py
@@ -26,7 +26,20 @@ import dns.renderer
 
 class Node:
 
-    """A Node is a set of rdatasets."""
+    """A Node is a set of rdatasets.
+
+    A node is either a CNAME node or an "other data" node.  A CNAME
+    node contains only CNAME, RRSIG(CNAME), NSEC, RRSIG(NSEC), NSEC3,
+    or RRSIG(NSEC3) rdatasets.  An "other data" node contains any
+    rdataset other than a CNAME or RRSIG(CNAME) rdataset.  When
+    changes are made to a node, the CNAME or "other data" state is
+    always consistent with the update, i.e. the most recent change
+    wins.  For example, if you have a node which contains a CNAME
+    rdataset, and then add an MX rdataset to it, then the CNAME
+    rdataset will be deleted.  Likewise if you have a node containing
+    an MX rdataset and add a CNAME rdataset, the MX rdataset will be
+    deleted.
+    """
 
     __slots__ = ['rdatasets']