diff --git a/src/site/apt/entities.apt b/src/site/apt/entities.apt
index 70113821e..d9f088808 100644
--- a/src/site/apt/entities.apt
+++ b/src/site/apt/entities.apt
@@ -19,8 +19,13 @@ How JPA is used in LibreCCM
     {{{./ccm-core/apidocs/index.html?org/libreccm/core/CcmObject.html}CcmObject}}.
     Usually we customise the table name to use underscores instead of camel case
     in the database. Also we usually customise the names of columns the use
-    underscores and only lower case letters. For examples look at the various 
-    examples in the code.
+    underscores. 
+   
+    <<Important: To ensure compatibility with the supported 
+    databases (H2, PostgresSQL and Oracle for now) use only uppercase letters 
+    for database objects like schemas, tables and columns.>>
+    
+    For examples look at the various examples in the code.
 
     Each entity may be accompanied by one or two helper classes. There should
     be an {{{Repository_classes}repository}} class for every entity. 
@@ -57,4 +62,4 @@ How JPA is used in LibreCCM
     
     If there are complex operations involving the entity these operations
     should encapsulated by a manager class. There are several examples in the
-    code.
\ No newline at end of file
+    code.