creating-dbt-models

# dbt Model Development **Read before you write. Build after you write. Verify your output.** ## Critical Rules 1. **ALWAYS run `dbt build`** after creating/modifying models - compile is NOT enough 2. **ALWAYS verify output** after build using `dbt show` - don't assume success 3. **If build fails 3+ times**, stop and reassess your entire approach ## Workflow ### 1. Understand the Task Requirements - What columns are needed? List them explicitly. - What is the grain of the table (one row per what)? - What calculations or aggregations are required? ### 2. Discover Project Conventions ```bash cat dbt_project.yml find models/ -name "*.sql" | head -20 ``` Read 2-3 existing models to learn naming, config, and SQL patterns. ### 3. Find Similar Models ```bash # Find models with similar purpose find models/ -name "*agg*.sql" -o -name "*fct_*.sql" | head -5 ``` Learn from existing models: join types, aggregation patterns, NULL handling. ### 4. Check Upstream Data ```bash # Preview upstream data if needed dbt show --select <upstream_model> --limit 10 ``` ### 5. Write the Model Follow discovered conventions. Match the required columns exactly. ### 6. Compile (Syntax Check) ```bash dbt compile --select <model_name> ``` ### 7. BUILD - MANDATORY **This step is REQUIRED. Do NOT skip it.** ```bash dbt build --select <model_name> ``` If build fails: 1. Read the error carefully 2. Fix the specific issue 3. Run build again 4. **If fails 3+ times, step back and reassess appr...