From 844596c3d0c88a3c547db7ceb5be74ece05939ee Mon Sep 17 00:00:00 2001
From: programarivm <info@programarivm.com>
Date: Thu, 26 Sep 2019 13:26:32 +0100
Subject: [PATCH] README update

---
 03-databases/GenealogicalTree.m | 57 +++++++++++++++++++++++++++++++++
 README.md                       | 16 +++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 03-databases/GenealogicalTree.m

diff --git a/03-databases/GenealogicalTree.m b/03-databases/GenealogicalTree.m
new file mode 100644
index 0000000..505b34e
--- /dev/null
+++ b/03-databases/GenealogicalTree.m
@@ -0,0 +1,57 @@
+
+; global array as a tree
+
+  w "Genealogical tree:",!
+
+; create global records
+
+  s ^gtree(0)="Oliver"
+  s ^gtree(0,0)="Jack"
+  s ^gtree(0,1)="Amelia"
+  s ^gtree(0,0,0)="Harry"
+  s ^gtree(0,0,1)="Emily"
+  s ^gtree(0,1,0)="Thomas"
+  s ^gtree(0,1,1)="Jessica"
+  s ^gtree(0,0,0,0)="Michael"
+  s ^gtree(0,0,0,1)="Olivia"
+  s ^gtree(0,0,1,0)="Robert"
+  s ^gtree(0,0,1,1)="Mary"
+  s ^gtree(0,1,0,0)="George"
+  s ^gtree(0,1,0,1)="Susan"
+  s ^gtree(0,1,1,0)="Charles"
+  s ^gtree(0,1,1,1)="Elizabeth"
+; ...
+  s ^gtree(0,0,0,0,0,0)="Thomas"
+
+; TODO: traverse the tree and display information
+; ...
+
+; retrieve a global record
+
+  w "^gtree(0,1,1) is ",^gtree(0,1,1),!
+
+; obtain data about a particular node
+; 0, the node does not exist
+; 1, the node exists, has no descendant
+; 10, the node exists, has no data, has descendant
+; 11, the node exists, has data, has descendant
+
+  w "$data(^gtree(0,2)) is ",$data(^gtree(0,3)),!
+  w "$data(^gtree(0,1,1,1)) is ",$data(^gtree(0,1,1,1)),!
+  w "$data(^gtree(0,0,0,0,0)) is ",$data(^gtree(0,0,0,0,0)),!
+  w "$data(^gtree(0)) is ",$data(^gtree(0)),!
+
+; remove the global array
+; 0, the node does not exist
+; 0, the node does not exist
+; 0, the node does not exist
+; 0, the node does not exist
+
+  w "Removing tree...",!
+
+  k ^gtree
+
+  w "$data(^gtree(0,2)) is ",$data(^gtree(0,3)),!
+  w "$data(^gtree(0,1,1,1)) is ",$data(^gtree(0,1,1,1)),!
+  w "$data(^gtree(0,0,0,0,0)) is ",$data(^gtree(0,0,0,0,0)),!
+  w "$data(^gtree(0)) is ",$data(^gtree(0)),!
diff --git a/README.md b/README.md
index 3553cef..69aa416 100644
--- a/README.md
+++ b/README.md
@@ -222,6 +222,22 @@ Copy the examples into your `~/.fis-gtm/V6.3-003A_x86_64/r` folder and run:
 
     Enter n: 9
     F(9) = 34
+
+## 3. Databases
+
+### [`GenealogicalTree.m`](https://github.com/programarivm/mumps-examples/blob/master/02-user-defined-functions/GenealogicalTree.m)
+
+    Genealogical tree:
+    ^gtree(0,1,1) is Jessica
+    $data(^gtree(0,2)) is 0
+    $data(^gtree(0,1,1,1)) is 1
+    $data(^gtree(0,0,0,0,0)) is 10
+    $data(^gtree(0)) is 11
+    Removing tree...
+    $data(^gtree(0,2)) is 0
+    $data(^gtree(0,1,1,1)) is 0
+    $data(^gtree(0,0,0,0,0)) is 0
+    $data(^gtree(0)) is 0
 ---
 
 ### Contributions