Common Data Elements (CDEs) define standardized key terms or concepts for diseases in form of a data dictionary that can be used in both relational and graph metadata models.
A data repository model defines the file and folder naming and structure as well as partially the file content (metadata definitions) and preferred format.
A graph metadata model defines a set of modular metadata schemas (including their relations) as architectural base of a graph database for describing the products represented in that database.
A relational metadata model defines a set of tabular metadata schemas (including their relations) as architectural base of a relational database for describing the products represented in that database.