Bridging Semantic Divides: Aligning Schemas and Ontologies in Software Architecture
Table of Contents
Meet the Teams
- Inventory, Storefront, ML - disjoint systems
The Problem
- No shared understanding of "Product"
- Hard to integrate and analyze data
Product Entity
sku (string) : Unique identifier for the product
name (string) : Name of the product
price (float) : Price of the product
category (string) : Category of the product
Inventory Team
sku (string) : Unique identifier for the product
quantity (int) : Quantity of the product in stock
reorderlevel (int) : Level at which a reorder should be triggered
Frontend Team
sku (string) : Unique identifier for the product
displayname (string) : Name displayed on the frontend
description (string) : Description of the product on the frontend
images (string list) : List of image URLs for the product
ML Team
sku (string) : Unique identifier for the product
predicteddemand (float) : Predicted demand for the product based on ML models
predictedsales (float) : Predicted sales for the product based on ML models
Key Questions
- What approaches help teams establish shared meaning?
- How to design an adaptable semantic integration layer?
- What tools exist for aligning schemas and ontologies?
Proposed Solution
- Build a semantic integration ontology
- Map local schemas into ontology
- Generate crosswalks between schemas
- Manage changes at integration layer
Approaches for Shared Meaning
- Cross-domain workshops
- Documentation of key terms
- Validation by domain experts
Adaptable Architecture
- Separate integration layer
- Well-defined interfaces
- Automated schema mapping
- Abstract over implementation details
Architectures
Ontology alignment, also known as ontology matching, is the process of determining correspondences between concepts in different ontologies. In the context of software design using architectures like Actors, Publish/Subscribe (Pub/Sub), Threads, and Event-Driven Architectures, ontology alignment can be seen as a way to harmonize the different views and models of the system represented in these architectures, thus enabling them to work together more effectively.
Actor Architecture
In an Actor architecture, each actor is an independent entity with its own state and behavior. Actors communicate with each other by sending and receiving messages. In terms of ontology alignment, this could mean ensuring that the messages sent between actors conform to a shared ontology, so that they can be correctly interpreted by the receiving actor redhat.com.
Publish/Subscribe (Pub/Sub) Architecture
In a Pub/Sub architecture, publishers send messages to topics, and subscribers receive messages from topics they are interested in. Ontology alignment in this context could involve ensuring that the messages published to a topic, and the expectations of subscribers to that topic, are based on a shared understanding of the message structure and semantics solace.com.
Threads
Threads are a way of allowing a program to do multiple things at once. Each thread in a program deals with a separate task. Ontology alignment in this context could involve ensuring that the data shared between threads is based on a common ontology, so each thread interprets the data correctly.
Event-Driven Architectures
In event-driven architectures, the state changes in a system (events) trigger the execution of certain actions. Ontology alignment in this context could involve ensuring that the definition and interpretation of events, and the actions triggered by them, are based on a shared ontology cloud.google.com.
For instance, the user context provided is a form of event-driven architecture where each function represents a state change or an event in the system. The movement from one function to the next is driven by the completion of the preceding function. In this scenario, ontology alignment would mean ensuring that the output of one function (event) aligns with the expected input of the next function in terms of structure, semantics, and data type. This ensures that each function can correctly interpret and process the data it receives.
In all these architectures, ontology alignment helps in maintaining consistency, enabling interoperability, and facilitating communication between different components or parts of the system. It ensures that despite the heterogeneity of these components, they can work together effectively by adhering to a shared understanding of the system's concepts and their relationships en.wikipedia.org.
Tools for Alignment
- GraphQL federation
- R2RML, R2O, SPARQL
- OpenAPI Specification
- SHACL validation
Outcomes
- Unified understanding of "Product"
- Joined data analysis opportunities
- Reduced duplication of effort
- Insulated from downstream changes
Questions
What approaches help teams establish shared meaning?
To establish a shared understanding of key terms like "Product", you can organize cross-domain workshops where teams can collaborate and define these terms. This is similar to the Stanford Linked Data Workshop where different teams worked together to understand linked data in a cultural heritage context guides.library.ucla.edu. Additionally, documenting the definitions of key terms can provide a reference point for all teams. Lastly, validation by domain experts can ensure that the shared meaning aligns with the industry standards and practical usage.
How to design an adaptable semantic integration layer?
A separate integration layer can be designed that interfaces well with the existing systems. This layer will handle the ontology mapping and changes in schemas, abstracting these complexities from the implementation details of the existing systems. The integration layer can also include automated schema mapping to adapt to changes in local schemas, similar to how CKAN’s harvesting framework retrieves, normalizes, and converts dataset metadata guides.library.ucla.edu.
What tools exist for aligning schemas and ontologies?
There are several tools that can be used for aligning schemas and ontologies. GraphQL federation can be used to build a unified data graph by combining multiple APIs semantic-web-journal.net. R2RML, R2O, and SPARQL are mapping languages that can create a bridge between databases and the semantic web link.springer.com. OpenAPI Specification can be used to standardize how APIs are described, helping in alignment guides.library.ucla.edu. Lastly, SHACL can be used for validating RDF graphs against a set of conditions guides.library.ucla.edu.
How to manage changes at the integration layer?
Changes at the integration layer can be managed by maintaining well-defined interfaces that allow the integration layer to communicate with the existing systems. Any changes in the ontology or schemas can be handled within the integration layer without affecting these interfaces. Automated schema mapping can be used to adapt to changes in local schemas and map them to the ontology.
By implementing these strategies and tools, you can achieve a unified understanding of "Product", provide opportunities for joined data analysis, reduce duplication of effort, and insulate your systems from downstream changes.