diff --git a/demos/er.html b/demos/er.html
index 347eb5e13..634a8f9e5 100644
--- a/demos/er.html
+++ b/demos/er.html
@@ -85,6 +85,30 @@
     >
     <hr />
 
+    <pre class="mermaid">
+      erDiagram
+        CAR ||--o{ NAMED-DRIVER : allows
+        CAR {
+          string registrationNumber PK
+          string make
+          string model
+          string[] parts
+        }
+        PERSON ||--o{ NAMED-DRIVER : is
+        PERSON {
+          string driversLicense PK "The license #"
+          string(99) firstName "Only 99 characters are allowed"
+          string lastName
+          string phone UK
+          int age
+        }
+        NAMED-DRIVER {
+          string carRegistrationNumber PK,FK
+          string driverLicence PK,FK
+        }
+        MANUFACTURER only one to zero or more CAR : makes
+    </pre>
+
     <script src="./mermaid.js"></script>
     <script type="module">
       mermaid.initialize({
diff --git a/docs/syntax/entityRelationshipDiagram.md b/docs/syntax/entityRelationshipDiagram.md
index 9837ad92d..f06af0c0b 100644
--- a/docs/syntax/entityRelationshipDiagram.md
+++ b/docs/syntax/entityRelationshipDiagram.md
@@ -200,14 +200,13 @@ The `type` and `name` values must begin with an alphabetic character and may con
 
 #### Attribute Keys and Comments
 
-Attributes may also have a `key` or comment defined. Keys can be "PK", "FK" or "UK", for Primary Key, Foreign Key or Unique Key. And a `comment` is defined by double quotes at the end of an attribute. Comments themselves cannot have double-quote characters in them.
+Attributes may also have a `key` or comment defined. Keys can be `PK`, `FK` or `UK`, for Primary Key, Foreign Key or Unique Key. To specify multiple key constraints on a single attribute, separate them with a comma (e.g., `PK,FK`).. A `comment` is defined by double quotes at the end of an attribute. Comments themselves cannot have double-quote characters in them.
 
 ```mermaid-example
 erDiagram
     CAR ||--o{ NAMED-DRIVER : allows
     CAR {
-        string allowedDriver FK "The license of the allowed driver"
-        string registrationNumber UK
+        string registrationNumber PK
         string make
         string model
         string[] parts
@@ -217,17 +216,21 @@ erDiagram
         string driversLicense PK "The license #"
         string(99) firstName "Only 99 characters are allowed"
         string lastName
+        string phone UK
         int age
     }
-    MANUFACTURER only one to zero or more CAR
+    NAMED-DRIVER {
+        string carRegistrationNumber PK,FK
+        string driverLicence PK,FK
+    }
+    MANUFACTURER only one to zero or more CAR : makes
 ```
 
 ```mermaid
 erDiagram
     CAR ||--o{ NAMED-DRIVER : allows
     CAR {
-        string allowedDriver FK "The license of the allowed driver"
-        string registrationNumber UK
+        string registrationNumber PK
         string make
         string model
         string[] parts
@@ -237,9 +240,14 @@ erDiagram
         string driversLicense PK "The license #"
         string(99) firstName "Only 99 characters are allowed"
         string lastName
+        string phone UK
         int age
     }
-    MANUFACTURER only one to zero or more CAR
+    NAMED-DRIVER {
+        string carRegistrationNumber PK,FK
+        string driverLicence PK,FK
+    }
+    MANUFACTURER only one to zero or more CAR : makes
 ```
 
 ### Other Things
diff --git a/packages/mermaid/src/docs/syntax/entityRelationshipDiagram.md b/packages/mermaid/src/docs/syntax/entityRelationshipDiagram.md
index a670c6837..abce89467 100644
--- a/packages/mermaid/src/docs/syntax/entityRelationshipDiagram.md
+++ b/packages/mermaid/src/docs/syntax/entityRelationshipDiagram.md
@@ -146,14 +146,13 @@ The `type` and `name` values must begin with an alphabetic character and may con
 
 #### Attribute Keys and Comments
 
-Attributes may also have a `key` or comment defined. Keys can be "PK", "FK" or "UK", for Primary Key, Foreign Key or Unique Key. And a `comment` is defined by double quotes at the end of an attribute. Comments themselves cannot have double-quote characters in them.
+Attributes may also have a `key` or comment defined. Keys can be `PK`, `FK` or `UK`, for Primary Key, Foreign Key or Unique Key. To specify multiple key constraints on a single attribute, separate them with a comma (e.g., `PK,FK`).. A `comment` is defined by double quotes at the end of an attribute. Comments themselves cannot have double-quote characters in them.
 
 ```mermaid-example
 erDiagram
     CAR ||--o{ NAMED-DRIVER : allows
     CAR {
-        string allowedDriver FK "The license of the allowed driver"
-        string registrationNumber UK
+        string registrationNumber PK
         string make
         string model
         string[] parts
@@ -163,9 +162,14 @@ erDiagram
         string driversLicense PK "The license #"
         string(99) firstName "Only 99 characters are allowed"
         string lastName
+        string phone UK
         int age
     }
-    MANUFACTURER only one to zero or more CAR
+    NAMED-DRIVER {
+        string carRegistrationNumber PK,FK
+        string driverLicence PK,FK
+    }
+    MANUFACTURER only one to zero or more CAR : makes
 ```
 
 ### Other Things