How to Fix dbt Dependency Errors

Dependency errors occur when your dbt models reference each other in ways that create conflicts or circular dependencies. These can be some of the most challenging errors to resolve.

Common Symptoms

• Circular dependency errors
• Self-referencing model issues
• Dependency chain failures
• Resource ordering problems

Understanding Dependencies

What is a Circular Dependency?

A circular dependency occurs when models reference each other in a loop:

Model A → Model B → Model C → Model A

This creates an impossible situation where each model needs the others to be built first. It also violates a key tenant of dbt which leverages a DAG(Directed Acyclic Graph), acyclic meaning that there are no cycles in the graph.

When this occurs, dbt will raise an error such as:

RuntimeError: Found a cycle: model.balboa.my_model --> model.balboa.some_model.v2

Solution Steps

Break Dependency Cycles

Common strategies:

Introduce Intermediate Models ```sql -- Instead of direct circular reference -- model_a.sql select * from {{ ref('model_b') }}

 -- model_b.sql
 select * from {{ ref('model_a') }}

 -- Create intermediate model
 -- model_a_intermediate.sql
 select * from raw_data

 -- model_a.sql
 select * from {{ ref('model_a_intermediate') }}

 -- model_b.sql
 select * from {{ ref('model_a') }}
 ```

Use the {{ this }} Reference sql -- For self-referencing models with current_data as ( select * from {{ this }} )

Restructure Model Relationships

1. Review your model architecture
2. Consider alternative data modeling approaches
3. Evaluate incremental modeling strategies

Best Practices

1. Design your data models with clear hierarchies
2. Document model dependencies
3. Regularly review model lineage
4. Keep transformation logic close to source data

Next Steps

If you're still experiencing issues:

1. Review your overall data architecture
2. Consider refactoring complex model relationships
3. Document your dependency structure
4. Implement incremental processing where appropriate

Remember: Sometimes the best solution is to rethink your data model structure rather than trying to force a complex dependency chain to work.