Entities (Graph vertices) Template (from node type) Instance (from template) Instance (from type) Relationships (graph edges) Relation from between a pair of nodes Mapping M to N (by intension) Explicit M to N (by extension) Encoding of information Consider 2 approaches DSL-like encoding Instance model has structure similar to service template Object tree encoding Instance model is encoded more naturally as on object tree Both are information preserving encodings So it’s possible to translated between them There was more interest in the Object tree encoding More natural traversal More natural representation Extensibility in terms of objects (you can represent anything you want) versus DSL Serialization Issues may want to include information defined from other standards/meta models Implementations may want to include additional information in instances E.g. resource mapping information Structural information indicating relationships among other entities Implementations may want to include information not part of TOSCA instances TOSCA does not have all the features to support object trees Referencing entities in other subtrees (can only reference specific instances by name, no collections) Generalized referencing that work in document, cross document with relative and absolute URIs Collections Referencing entities in ordered collections Referencing entities by key
Entities (Graph vertices) Template (from node type) Instance (from template) Instance (from type) Relationships (graph edges) Relation from between a pair of nodes Mapping M to N (by intension) Explicit M to N (by extension) Encoding of information Consider 2 approaches DSL-like encoding Instance model has structure similar to service template Object tree encoding Instance model is encoded more naturally as on object tree Both are information preserving encodings So it’s possible to translated between them There was more interest in the Object tree encoding More natural traversal More natural representation Extensibility in terms of objects (you can represent anything you want) versus DSL Serialization Issues may want to include information defined from other standards/meta models Implementations may want to include additional information in instances E.g. resource mapping information Structural information indicating relationships among other entities Implementations may want to include information not part of TOSCA instances TOSCA does not have all the features to support object trees Referencing entities in other subtrees (can only reference specific instances by name, no collections) Generalized referencing that work in document, cross document with relative and absolute URIs Collections Referencing entities in ordered collections Referencing entities by key