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Event Data

Event data and master data are core concepts of traceability. The frameworks described in this knowledge base build on top of the EPCIS 2.0 definitions for these concepts. Event data describes things…

John Heggelund
Updated by John Heggelund

Event data and master data are core concepts of traceability. The frameworks described in this knowledge base build on top of the EPCIS 2.0 definitions for these concepts.

Event data describes things that happen to product instances at specific moments in time. An example might include, "At 1:23 pm on 15 March 2004, Product A was shipped to Location B." Master data gives context to the event data by providing details about product A and Location B.

Product A:

  • Name: 12oz Rib Eye Steak
  • GTIN: urn:gdst:example.org:product:class:example_prefix.A

Location B:

  • Name: Beef Distributor Warehouse B
  • Street Address: 123, Warehouse B, Houston, Texas, 77065
Event data grows in quantity as more business is transacted and refers to things that happen at specific moments in time. (EPCIS 2.0)

Understanding Events

Event data is composed of individual events.

An event is:

  1. A record that associates EPCs with a moment in time (eventTime).
  2. Structured based on one of the five canonical Event Types
    1. ObjectEvent
    2. AggregationEvent
    3. AssociationEvent
    4. TransformationEvent
    5. TransactionEvent
  3. Immutable after successful submission, ensuring integrity and an audit trail.

Event Data serves as the primary data source for answering three classes of visibility queries:

  1. Where is it?
  2. What is its history?
  3. What happened to it?

Event Structure and Composition

Core Composition of a Traceability Event

Component

Nomenclature

Data Type / Nature

Purpose within Event Data

Event Type

ObjectEvent, AggregationEvent, etc.

Qualified Name (URI)

Determines the schema and the nature of the captured action. It is the structure classifier.

Event Fields

eventTime, bizLocation, bizStep, epcList

Primitive Types (xs:dateTime, URIs, Lists), URI (gs1:EventID)

Named fields that populate the contextual details (When, Where, Why, Who/What).

Event Identifier

eventID

URI (gs1:EventID)

A cryptographically strong identifier to track the individual event. Vital for deduplication and referencing.

User Extensions

N/A

User-defined Types (Custom Namespace)

Allows proprietary, business-specific data to be encapsulated within the event without violating core EPCIS interoperability.

Event Data vs Master Data

The separation between Event Data and Master Data is architecturally central to EPCIS and is based on three key vectors: Time, Content, and Mutability.

Technical and Functional Differentiation

Characteristic

Event Data (Transaction Facts)

Master Data (Reference Data)

Temporal Volatility

High: Capture of point-in-time events, resulting in high record volume. - Example: Recording 300 ObjectEvents in a single day, each with a unique eventTime, such as: "eventTime": "2025-11-25T14:00:00Z".

Low: Descriptive attribute that changes slowly or rarely. - Example: The name or description of the product (GTIN) associated with those 300 events might have only been updated once in the last year.

Mutability (Design Principle)

Immutable (Append-only): Event Data is a historical record. Corrections require submitting a new voiding/replacing event. - Example: If the bizStep was incorrectly logged as receiving instead of shipping, the original event persists. A subsequent ObjectEvent must be submitted with the isA: "EPCIS-Event-Correction" tag and a reference to the erroneous event.

Mutable: Can be updated (e.g., change in a bizLocation´s address). Updates impact the interpretation of all historical events referencing them. - Example: If the physical address of a bizLocation is updated in the Master Data today, all historical events (Event Data) referencing that SGLN immediately gain the new address as their location context.

Semantic Function

Occurrence (What Happened): Answers questions about an item´s history and temporal position. - Example: Event Data states: "EPC 'X' transitioned disposition to 'damaged' on day 'T'". (A semantic of fact).

Context (What It Is): Provides the description of the entities (EPC, Location, Partner) involved in the event. - Example: Master Data states: "'damaged' means 'unsaleable product, awaiting disposal', as per internal policy." (The definition and context of that fact).

Identifier Usage

Usage Source: Contains resolvable references (URIs) to entities. - Example: The bizLocation field contains the URI: urn:epc:id:sgln:0012345.54321.0.

Definition Source: Defines and stores the attribute associated with those identifiers. - Example: The Master Data system stores: 0012345.54321.0 (ID) possesses the attributes "Name: Lisbon", "Address: 123, XYZ Street", "Lat/Lon: -25.44, -49.27".

Additional Resources

The Traceability Framework Implementation Guide

The following documents constitute the primary mapping resource, applying EPCIS directly to the business processes:

  1. Global Traceability Frameworks for Beef & Leather: This is the overarching document. It sets the high-level context and the Framework Requirements, defining which data (Data Collection) is necessary for the Event Data.
  2. Critical Tracking Events (CTEs): This group of articles forms the basis of the mapping. These articles define the Event Types that are mandatory for each step in the value chain:
    1. Example Event Mapping (Transformation Event, Shipping Event, etc.): These articles detail the one-to-one mapping. They instruct, for instance, which specific bizStep and disposition must be used when a Receiving Event or Shipping Event occurs in the project.
    2. Cattle Birthing: This is a crucial CTE that instructs the creation of the first Traceability Event, establishing the animal´s origin (sourceList).

Identification and Context Resources

Mapping the Event Data is incomplete without the rules defining how identifiers (EPCs) and contextual data (Master Data) must be structured.

  1. GFTBL Identifiers: This article is vital. It defines the encoding rules for transforming the internal IDs (for animals, cases, locations) into the required EPC URIs and SGLN URIs used in the epcList and bizLocation fields of the Event Data.
  2. Master Data Mapping: This article acts as the contextual resource. It outlines the Master Data attributes (such as the full legal name of a farm) that are referenced by, but not stored in, the Event Data.
  3. JSON Schemas: This technical resource defines the exact syntax and data structure to ensure the Traceability Events generated are compliant and acceptable to data exchange systems (Data Exchange).

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