diff --git a/doc/DATABASE.md b/doc/DATABASE.md
index e6e96d6..6c5f403 100644
--- a/doc/DATABASE.md
+++ b/doc/DATABASE.md
@@ -4,7 +4,8 @@
 
 - `l:<md5>` key/value -> {sha1, sha1}
 - `h:<sha1>`` hash -> keys from NSRL or other data sources
-- `p:<sha1>` set -> {sha1, sha1} for the parents of a hash (e.g. packages)
+- `p:<sha1>` set -> {sha1, sha1} for the parents of a hash (such as original packages)
+- `c:<sha1>` set -> {sha1, sha1} for the children of a hash (such as files contained in a package)
 
 ### Standard keys