refactoring-dbt-models

# dbt Refactoring **Find ALL downstream dependencies before changing. Refactor in small steps. Verify output after each change.** ## Workflow ### 1. Analyze Current Model ```bash cat models/<path>/<model_name>.sql ``` Identify refactoring opportunities: - CTEs longer than 50 lines → extract to intermediate model - Logic repeated across models → extract to macro - Multiple joins in sequence → split into steps - Complex WHERE clauses → extract to staging filter ### 2. Find All Downstream Dependencies **CRITICAL: Never refactor without knowing impact.** ```bash # Get full dependency tree (model and all its children) dbt ls --select model_name+ --output list # Find all models referencing this one grep -r "ref('model_name')" models/ --include="*.sql" ``` **Report to user:** "Found X downstream models: [list]. These will be affected by changes." ### 3. Check What Columns Downstream Models Use **BEFORE changing any columns, check what downstream models reference:** ```bash # For each downstream model, check what columns it uses cat models/<path>/<downstream_model>.sql | grep -E "model_name\.\w+|alias\.\w+" ``` If downstream models reference specific columns, you MUST ensure those columns remain available after refactoring. ### 4. Plan Refactoring Strategy | Opportunity | Strategy | |-------------|----------| | Long CTE | Extract to intermediate model | | Repeated logic | Create macro in `macros/` | | Complex join | Split into intermediate models | | Multiple concerns...