Attribute Groups in SFMC | Peoplewoo Skills

In Salesforce Marketing Cloud (SFMC), building relationships between Data Model Objects (DMOs) or Data Extensions (DEs) forms the backbone of a connected data ecosystem. These relationships are essential for unlocking dynamic segmentation, personalized customer journeys, and 360° audience insights.

Whether you’re managing email campaigns, mobile engagement, or personalized automation, understanding how to model your data and define relationships is a must-have skill for every SFMC professional.

Why Relationships Between Data Extensions Matter

Data rarely lives in a single place. Your customer’s information may be scattered across multiple data extensions — one storing profile data, another storing transactional details, and another capturing behavioral data. Without relationships, these datasets remain disconnected, preventing you from understanding the full customer journey.

Creating relationships allows SFMC to recognize that these records belong to the same individual. This helps marketers:

• Unify customer data from multiple touchpoints.
• Design more accurate audience segments.
• Trigger real-time, data-driven customer journeys.
• Maintain clean, organized, and reusable data models.

What Are Data Model Relationships in SFMC?

A data model relationship in SFMC is a connection between two or more Data Extensions based on a shared key or field, such as Contact Key, Email Address, or Subscriber ID. These relationships help link data from various sources into a single customer view.

Relationships are primarily used within:

• Contact Builder – to visually define and manage relationships.
• Audience Builder – for segmentation and targeting.
• Journey Builder – to use related data as entry sources or filters.
• Automation Studio / Query Activities – to perform SQL joins across related DEs.

Types of Relationships in SFMC

Before building relationships, it’s important to understand how different types of relationships define data behavior.

How to Build Relationships in Contact Builder

Follow these steps to create a relationship between two Data Extensions inside SFMC:

1. Go to Contact Builder > Data Designer.
2. Select the Attribute Group where you want to add relationships.
3. Click on the primary Data Extension you want to connect.
4. Click on Create Relationship and choose another Data Extension.
5. Select the common field that will serve as the join key (such as Contact Key or Email Address).
6. Define the relationship type (One-to-One or One-to-Many).
7. Click Save and validate the relationship visually in the data model diagram.

Real-Life Example: Subscriber and Purchase History

Imagine you have the following Data Extensions:

• Subscribers_DE — Contains SubscriberKey, Name, Email, Country
• Purchases_DE — Contains SubscriberKey, Item, Amount, Date

You can link them using SubscriberKey in a One-to-Many relationship. This setup allows you to perform advanced use cases like:

• Creating a segment of users who purchased specific products.
• Sending post-purchase recommendations based on previous orders.
• Triggering abandoned cart journeys for incomplete purchases.
• Tracking lifetime value and purchase frequency for loyalty programs.

Understanding Common Join Fields

Data Relationship Best Practices

• Always use Contact Key as the unique identifier where possible.
•  Avoid circular relationships or linking the same DE multiple times.
•  Ensure that all DEs have Primary Keys defined.
•  Document your relationships using a Data Model Diagram for future reference.
•  Use Query Studio or Data Views to validate your data joins.
•  Keep your data model optimized — avoid linking too many DEs unnecessarily.

Advanced Tip: SQL Joins in SFMC

If you prefer working with SQL, you can create relationships programmatically using JOIN statements inside Automation Studio. For example:

SELECT s.SubscriberKey, s.Email, p.Item,
p.Amount FROM Subscribers_DE s INNER JOIN Purchases_DE p ON s.SubscriberKey =

p.SubscriberKey WHERE p.Amount > 100

This query returns all subscribers who made purchases greater than 
$100 — perfect for building high-value customer segments.

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