In the world of data project management, unexpected challenges often arise, particularly when dealing with complex modeling and dependencies.
Here at LoopStudio, we recently encountered a unique problem while working on a project related to DBT (Data Build Tool) that isn’t widely discussed in documentation or courses.
This issue might resonate with many working on #data-projects, so I wanted to share our experience and solution.
In many scenarios, data models are built based on others. For example, a
stg_customer model might lead to the creation of a
But what happens when
dim_customer has a Foreign Key (FK) dependency on
dim_customer can only be created after a record in
dim_address has been inserted or created?
DBT doesn’t inherently guarantee or define the order of model creation. Beyond using
ref, which we typically employ to build one model based on another, there’s a complexity when a model isn’t built on another but is instead simply related by a constraint.
To address this, we can use
depends_on to enforce dependencies. This ensures that
dim_customer depends on
dim_customer will only execute after
dim_address has finished executing.
This approach effectively resolves the issue of managing dependencies between models that aren’t directly built from one another but are instead linked by a constraint.
Visualizing the Solution with DBT Docs:
dbt docs, we can visualize how our Directed Acyclic Graph (DAG) is structured. As shown in the documentation, there are clear relationships not only between the sources and the marts but also among the marts themselves.
This case study highlights an important aspect of working with DBT in data projects. Understanding and manipulating the dependencies can be crucial for the successful execution of complex data models.
Sharing these insights contributes to the broader community’s knowledge and helps in tackling similar challenges.