Knowledge Hub

A new but very known term, folks from Data World are aware of Metadata but Meta Metadata is something which is just surfaced the Data World and for me it’s again a game changer.

Let’s decode it…..

We all know what Metadata is, it’s Data About Data. Please refer to the Metadata as separate topic in this book.

Let me try to make it as simple as possible with a few examples.

For example, a column i.e., Data Of Birth (DOB) is technical metadata right? Now, when we go to the next level and tag, this DOB is for parents, children, for employees or for insurance policy maker that make the DOB attribute more relevant.

Another example can be Weight column, now value in this field is in numbers or digit but by looking in the value we can’t make it out whether this weight is for a person or an object, and further which object e.g., furniture or something else etc.

Giving more info about Metadata is called Meta Metadata.

Ontology or Knowledge Modelling is the practice of defining a formal and structured representation of knowledge within a domain. It identifies the important concepts, shows how they are related, and defines rules that govern those relationships. The purpose is to create a shared understanding that can be interpreted consistently by both humans and machines.

The main goal of Ontology Modelling is to build a framework that supports semantic clarity, interoperability, and reasoning. Unlike traditional data models that primarily focus on structure and storage, ontologies are designed so that systems can understand meaning and draw logical conclusions from it. This makes them especially valuable in environments where information must be integrated across different systems and interpreted intelligently.

Ontologies go beyond simple definitions of concepts. They define categories, hierarchies, constraints, and rules within a domain. For example, in a healthcare context, an ontology may define that a Patient undergoes a Treatment, and that Treatment can be classified as either a Procedure or a Medication. It may further define that a Medication is a type of Therapeutic Intervention. By establishing such hierarchies and relationships, the ontology provides a structured knowledge framework rather than just isolated definitions.

Metagraph Modelling is an advanced form of graph-based modelling in which nodes and relationships can themselves represent groups, sets, or even entire subgraphs. In other words, it allows relationships to carry their own structure and meaning. This makes it possible to represent complex, multi-level interactions that traditional graph models cannot fully capture.

The primary goal of Metagraph Modelling is to provide a more expressive framework for modelling context, grouping, and higher-order relationships. While a standard graph connects entities through simple relationships, a metagraph can describe relationships about relationships. This added expressiveness is particularly useful in domains where context, provenance, and interaction details are as important as the entities themselves.

To understand the difference, consider a simple graph example. In a loan system, we might represent the fact that a Customer applies for a Loan Application. In a traditional knowledge graph, this would appear as a node for the Customer, a node for the Loan Application, and an edge labeled appliesFor connecting them. This captures the relationship, but it does not fully describe the circumstances under which the application occurred.

Metadata Modelling is the discipline of designing structured frameworks that describe data about data. It defines how business, technical, and operational descriptors are captured, organized, and related so that data assets can be understood, discovered, traced, and governed consistently across the enterprise.

The primary goal of metadata modelling is to establish a structured and standardized approach to cataloguing and managing metadata. By doing so, organizations can improve compliance, strengthen data governance, enhance data quality, and increase trust in analytical and operational systems.

Metadata modelling focuses on descriptors such as:

• Business definitions
• Data ownership and stewardship
• Lineage (upstream and downstream data flow)
• Data source systems
• Refresh frequency
• Sensitivity classification
• Quality rules and thresholds
• Storage location and format

Unlike ontologies, which emphasize semantic meaning and relationships between business concepts, metadata modelling emphasizes the management attributes of data assets. It does not primarily answer “What does a Loan mean?” but rather “Where does the Loan data come from?”, “Who owns it?”, “How often is it refreshed?”, and “Is it sensitive?”

ISO 11179 is an international standard that provides guidelines for the representation and management of metadata for describing data and information resources. In simpler terms, it offers a standardized way to organize and describe data, making it easier to understand, share, and manage.

Let's break down ISO 11179 in more detail:

As we have read in Metadata Management topic, Metadata is Data about Data. It describes the characteristics, properties, and context of data, helping users understand what the data is, how it was collected, and how it can be used.

ISO 11179 focuses on standardizing the way metadata is defined, organized, and managed. It provides a common framework for describing data elements, ensuring consistency and clarity in data descriptions. The standard helps organizations create a common language and structure for describing data, making it easier for different systems and people to understand and use the data.

A MetaGraph provides information about the structure, schema, and semantics of a knowledge graph within a graph database. It essentially acts as a "graph of metadata" that defines how entities (nodes) and their relationships (edges) are organized and interact, including their attributes, constraints, and interdependencies.

‘The Metadata of Knowledge Graphs in Graph Databases.’

In the world of data management, the term MetaGraph represents an advanced layer of abstraction that encompasses the metadata of a knowledge graph. While knowledge graphs are designed to represent relationships between entities, a MetaGraph serves as the blueprint that defines the structure, schema, and semantics of those relationships. This topic delves into the concept of MetaGraph, their importance, use cases, and their impact on the evolving landscape of graph databases.

MetaGraph is an enabler for a complete digital twin of simple to complex reality. The MetaGraph technology offers a cutting-edge approach to define, manage and utilizing metadata in a digital ecosystem – thus providing rich context to data across functions and systems. This is critical for AI, machine learning and data driven as quality in decisions based on facts become more central to industry transformations. The demand for high-quality, relevant data has never been greater. In the end the MetaGraph can enhance how businesses operate and innovate.

DOGs, or Data Object Graphs, represent data objects and the relationships between them in the form of a graph. Instead of organizing data only in tables and rows, this approach visualizes data as connected objects.

In a Data Object Graph:

• A node represents a data object (such as Customer, Product, Order, or Employee).
• An edge represents a relationship between those objects (such as buys, works in, manages, owns).

This way of representing data focuses on how objects are connected rather than how they are stored.

Why Data Object Graphs Matter

Traditional relational systems organize data into tables. While this structure is powerful, it sometimes hides the complexity of relationships. In real-world business environments, data is deeply interconnected.

For example:

• A customer places multiple orders.
• An order contains multiple products.
• A product belongs to a category.
• An employee manages multiple customers.