Data Modeling

Last updated Nov 21, 2024

Data modeling has changed; when I started (~20 years ago), choosing between Inmon and Kimball was common.

Today, in data engineering, data modeling creates a structured representation of your organization’s data. Often illustrated visually, this representation helps understand the relationships, constraints, and patterns within the data and serves as a blueprint for gaining business value in designing data systems, such as data warehouses, lakes, or any analytics solution.

In its most straightforward form, data modeling is how we design the flow of our data such that it flows as efficiently and in a structured way, with good data quality and as little redundancy as possible.

Abstract

Data modeling and design are key to creating usable data systems. Designing involves different high-level modeling, such as generation or source database design, data integration, ETL processes, data warehouse schema creation, data lake structuring, BI tool presentation layer design, machine learning, or AI feature engineering.

Further details design involves moving from a Logical Data Model to a Physical Data Model, defining tables with dimensions and facts, partitioning and indices, relationships, constraints, etc. Further, the architect needs to be aware of redundancy and denormalization, the grain of the table, and data optimized for efficient queries of dashboards, ad-hoc notebooks, or data apps, ensuring data quality throughout the process.

What do you think about different levels of modeling? Generally, when I started (20 years ago), choosing between Inmon and Kimball was common. But today, there are so many layers, levels, and approaches. Did you find a good way of separating or naming the different “levels” (still unsure about levels) to clarify what is meant? Below is a list of what I think so far (I also wrote extensively about it, in case of interest).

• Levels of Modeling
  • Generation or source database design
  • Data integration
  • ETL processes
  • Data warehouse schema creation
  • Data lake structuring
  • BI tool presentation layer design
  • Machine learning or AI feature engineering
• Data Modeling Approaches
  • Conceptual, Logical to physical Data Models
  • Other lesser known: Hierarchical Data Modeling, Network Data Modeling and Object-Role Modeling
• Data Modeling Techniques
  • Dimensional Modeling
    • Fact Table, Dimensions
  • Data Vault Modeling
  • Anchor Modeling
  • Bitemporal Modeling
  • Entity-Centric Data Modeling (ECM)
  • Focal Modeling
  • Activity Schema
• Data Architecture Pattern
  • General Purpose Data Architecture Pattern
    • Staging, Cleansing, Core, Data Mart (Classical Architecture of Data Warehouse) or Medallion Architecture
  • Specialized
    • Batch vs. Streaming (Streaming vs Batch in Orchestration)
    • Data Lake/Lakehouse vs. Data Warehouse Pattern
    • Semantic Layer (In-memory vs. Persistence or Semantic vs. Transformation Layer)
    • Modern Data Stack / Open Data Stack Pattern
    • many more: Data Modeling- The Unsung Hero of Data Engineering- Data Architecture Pattern, Tools and The Future (Part 3)

LinkedIn Post and Discussion, X/Twitter and dbt Slack. Links (from the post): Data Model Matrix.

See Data Modeling Techniques

Common approaches are well explained here:

• Dimensional Modeling
  • Data Lake File Format -> Data Lake Table Format
• Relational Model
• Graph Data Modeling ?

others

• streaming vs batch processing
• RW Data Pipeline Design Patterns - 1. Data Flow Patterns · Start Data Engineering (Nice Visual)

Data Modeling is as much about Data Engineering Architecture as it is about modeling the data only. Therefore besides the below links, many approaches and common architecture you can find in Data Engineering Architecture.

It’s getting more about language than really modeling, Shane Gibson says on Making Data Modeling Accessible. For example, a Data Scientist speaks Wide Tables, a Data engineer talks about facts and dimensions, etc., it’s what I call the different levels of data modeling.

See more on Data Modeling is changing.

See Data Modeling Tools.

Mostly, modeling happens outside the data platform (Logical Data Model). I’d argue you should model on Paper, Excalidraw, or sophisticated model tools (see more on Data Modeling: Architecture Pattern, Tools and the Future (Part 3)) before integrating into any tool.

The next layer (Physical Data Model) would be dbt as the tool I’d use to implement the modeled architecture. It’s SQL, everybody understands, and you get documentation out of the box. Integrated into Dagster, you get a high-level data-flow model from tables to data assets.

More on Logical vs. Physical see Conceptual, Logical to physical Data Models.

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See Data Modeling Languages, or also on Data Model Engines.

See Data Modeling Frameworks

# Differences to Dimensional Modeling

See Data Modeling – The Unsung Hero of Data Engineering- Modeling Techniques and Data Architecture Patterns (Part 2).

There is more than dimensional modeling:

• hierarchies, semistructured sources, conformed dimensions, historical updates, and the logic used to keep them up to date
• Source: Serge Gershkovich on LinkedIn

Data modeling, incredibly Dimensional Modeling with defining facts and dimensions, is a big thing for a data engineer, IMO. It would help if you asked vital questions to optimize for data consumers. Do you want to drill down the different products? Daily or monthly enough —keywords Granularity and rollup.

It also lets you consider Big-O implications regarding how often you touch and transfer data. I’d recommend the old  Data Warehouse Toolkit from Ralph Kimball, which initiated many of these concepts and is still applicable today. Mostly, it’s not done in the beginning, but as soon as you get bigger, you wish you had done more :)

Relates to [.

Links:

• Honest No-BS Data Modeling w/ Juan Sequeda
• What Is Data Modeling? - DATAVERSITY
• Modern Data Modeling Beyond The Theory - With Veronika Durgin - YouTube

I wrote an extensive three-part series about data modeling; check it out on my blog:

1. An Introduction to Data Modeling
2. Modeling Approaches and Techniques
3. Architecture Pattern, Tools and the Future

Origin:
References: enterprise architecture modeling
Created 2022-09-24