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Creating High-Level Model Diagrams

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Creating effective high-level model diagrams is a critical skill for data engineers, especially when interviewing at FAANG and other top tech companies. These diagrams provide a clear, concise overview of a data model's structure and relationships, allowing you to quickly communicate your design approach and demonstrate your understanding of complex data systems.

In this lesson, we'll explore techniques for rapidly developing high-level model diagrams that effectively capture business requirements and showcase your data modeling expertise. We'll focus on translating business needs into visual representations that highlight key entities, their relationships, and the overall structure of your proposed solution.

Understanding the Business Context

Before creating a high-level model diagram, thoroughly analyze the business requirements. Look for:

  • Analytical use cases
  • Key metrics and KPIs

Creating and Interpreting Bubble Charts

Bubble charts are an effective way to visually represent high-level dimensional models in interviews. They consist of:

  • A central fact table (usually represented by a rectangle)
  • Surrounding dimension tables (usually represented by circles)
  • Lines connecting related tables

Example: Streaming Service

[User Dimension] ----- [Content Dimension]
       |                     |
       |     +---------+     |
       +-----| Viewing |-----+
             |  Fact   |
       +-----| Table   |-----+
       |     +---------+     |
       |                     |
[Time Dimension] ----- [Device Dimension]

When creating bubble charts:

  1. Place the fact table in the center
  2. Arrange dimensions around the fact table
  3. Use lines to show relationships
  4. Label each table clearly

In an interview, quickly sketch this chart to visualize your model. It serves as a great talking point and demonstrates your ability to conceptualize complex relationships.

Common examples

Let's walk through creating high-level dimensional models for common scenarios:

E-commerce platform: order management

Business Process: Order Processing

Fact Table: Order Facts

  • Facts: Order Total, Number of Items, Discount Amount

Dimensions:

  • Customer Dimension
  • Product Dimension
  • Time Dimension
  • Store Dimension (for multi-channel retailers)
  • Promotion Dimension

Bubble Chart:

Order management bubble chart

Social media: user engagement

Business Process: Content Interaction

  • Fact table: Interaction Facts
  • Dimensions: User, Content, Time, Device
  • Facts: Likes, Comments, Shares, View Duration

Bubble Chart:

[User] ---- [Interaction Facts] ---- [Content]
 |                |                    |
[Device]        [Time]            [Content Type]

Streaming service: viewing behavior

Business Process: Content Consumption

  • Fact table: Viewing Facts
  • Dimensions: User, Content, Time, Device, Location
  • Facts: View Duration, Completion Rate, Rating

Bubble Chart:

[User] ---- [Viewing Facts] ---- [Content]
 |                |                  |
[Device]       [Time]             [Genre]
 |
[Location]
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