diff --git a/.gitignore b/.gitignore
index 7431dee..b60cd9f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -100,6 +100,9 @@ ENV/
 .spyderproject
 .spyproject
 
+# PyCharms project settings
+/.idea
+
 # Rope project settings
 .ropeproject
 
diff --git a/README.md b/README.md
index 75fcb22..4185436 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,8 @@ This repository contains:
 * C# code for the web interface (folder IEDC_webapp)
 * Sample code for the pymysql interface (folder mySQL_Python_Examples)
 
-Last change of this document: October 19th, 2018.
+Database schema diagram:
 
+![IEDC relational database schema diagram, showing only main tables and relationships](/doc/IEDC-EER-MainTables.JPG)
 
+Last change of this document: October 29th, 2018.
diff --git a/doc/IEDC-EER-AllTables.JPG b/doc/IEDC-EER-AllTables.JPG
new file mode 100644
index 0000000..8735bd0
Binary files /dev/null and b/doc/IEDC-EER-AllTables.JPG differ
diff --git a/doc/IEDC-EER-MainTables.JPG b/doc/IEDC-EER-MainTables.JPG
new file mode 100644
index 0000000..f08c2ee
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