Update MediaType, add SpdxId

model/Core/Datatypes/DateTime.md

@@ -15,6 +15,7 @@ The specific format is one of the most commonly used ISO-8601 formats.
 ## Metadata
 
 - name: DateTime
+- SubclassOf: xsd:string
 
 ## Format
 

model/Core/Datatypes/MediaType.md

@@ -4,19 +4,20 @@ SPDX-License-Identifier: Community-Spec-1.0
 
 ## Summary
 
-Standardized way of indicating the type of content of an Element. A String constrained to the RFC 2046 specification.
+Standardized way of indicating the type of content of an Element. A String constrained to the RFC 6838 specification.
 
 ## Description
 
-A MediaType is a string constrained to the RFC 2046 specification. It provides a standardized
-way of indicating the type of content of an Element.
+A MediaType is a string constrained to the RFC 6838 specification, and includes
+`type-name`, `subtype-name` and optional `parameters`.
+It provides a standardized way of indicating the type of content of an Element.
 A list of all possible media types is available at https://www.iana.org/assignments/media-types/media-types.xhtml.
 
 ## Metadata
 
 - name: MediaType
+- SubclassOf: xsd:string
 
 ## Format
 
-- pattern: ^[^\/]+\/[^\/]+$
-
+- pattern: ^([a-zA-Z0-9][-a-zA-Z0-9!#$&^_.+]{0,126})\/([a-zA-Z0-9][-a-zA-Z0-9!#$&^_.+]{0,126})(;.+)?$

model/Core/Datatypes/SemVer.md

@@ -14,6 +14,7 @@ that is following the specification of [Semantic Versioning 2.0.0](https://semve
 ## Metadata
 
 - name: SemVer
+- SubclassOf: xsd:string
 
 ## Format
 

model/Core/Datatypes/SpdxId.md

@@ -0,0 +1,21 @@
+SPDX-License-Identifier: Community-Spec-1.0
+
+# SpdxId
+
+## Summary
+
+An IRI that references an SPDX Element
+
+## Description
+
+URIs / IRIs are used for naming resources, locating resources or both.
+SpdxId is an IRI that names an SPDX Element.
+
+## Metadata
+
+- name: SpdxId
+- SubclassOf: xsd:anyURI
+
+## Format
+
+