![[photo-1501947248335-9b511c0cb5c9.jpg]] Photo by [Tom Roberts](https://unsplash.com/es/@tomrdesigns?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText) on [Unsplash](https://unsplash.com/photos/6GAxwyTCcPQ?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText) What is "x2x" model good for and why do we need it? You will learn basics of structural relations in the MetaX and how to visualize them. > Entity–relationship modeling was developed for database and design by Peter Chen and published in a 1976 paper,[1] with variants of the idea existing previously.[2] Some ER models show super and subtype entities connected by generalization-specialization relationships,[3] and an ER model can be used also in the specification of domain-specific ontologies. [1] The "**x2x**" model is fundamentally an essential part of every concept and x2x semantic model we use inside MetaX is a model of concepts further referencing logical and physical entities.![[Pasted image 20230708132513.png|Figure 1: x2x model]] The "x2x" symbol literally means "anything" connected to "anything". Why anything to anything? Well, from ontology perspective this will enable us to define inclusive and exclusive architecture of open and closed ecosystems ranging from social networks to multi-tenant cloud architecture with consistent behavior based patterns (will spend more time on ecosystem patterns at dedicated article in close future). - The "**X**" is any entity connected to another entity or abstract crossing boundary of abstraction level - The "**2**" is connection or relation characterized by specific attributes and associated patterns > There is a tradition for ER/data models to be built at two or three levels of abstraction. Note that the conceptual-logical-physical hierarchy can be used in other kinds of specification, and is different from the three schema approach to software engineering. [2] ![[Pasted image 20230708132534.png|Figure 2: x2x visualization]] Visualization of #x2x model is extremely simple and powerful at the same time. Full line represents closed (private) or open (public) relationship; Circle represents Entity or Domain (Boundary). By extension of this simple construct, we can define ratio (just like in ER models), isolation and sharing levels for relations and communication as well as tenant building blocks (picture below). ![[Pasted image 20230708132552.png|Figure 3: x2x relations]] > The full meaning of a concept is constituted by two aspects, its intension and its extension. The first part comprises the embedding of a concept in the world of concepts as a whole, i.e. the totality of all relations to other concepts. The second part establishes the referential meaning of the concept, i.e. its counterpart in the real or in a possible world [3] Now we are ready to define structural relationship within the ecosystem and establish high level relationship categorization ( #Open / #Closed / #Hybrid). ![[Pasted image 20230708132629.png|Figure 4: x2x structural relationships]] Great! Now imagine to create a model of hundreds of entities and their connections on the screen. Overwhelming right? That is where we start x2x MetaX consolidation. Simple visualization (picture below) of consolidated x2x relations into the networks shows easy transition from connections and single relations into pattern based networks with associated behavior, The ratio exemplifies decomposition of these networks into entities and their relations. ![[Pasted image 20230708132650.png|Figure 5: x2x consolidation to abstracts and networks]] The "x2x"model is introducing a foundation for visualization of ecosystem abstracts and their dependencies crossing abstraction layers beyond existing visualization techniques and triplets used (RDF) in graph databases. ## References [1] PETER CHEN; MIT; The Entity-Relationship Model-Toward a Unified View of Data, ACM Transactions on Database Systems, Vol. 1, No. 1, March 1976 [2] Wikipedia; Definitions [3] Hermann Helbing; The Role of Intentional and Extensional Interpretation in Semantic Representations - The Intentional and Preattentional Layers in Multinet; January 2007 ## Related to [[MetaX - The Definition]] [[MetaX Semantic Model]] [[MetaData and the case for universal semantic identifiers]]