---
description: Mandatory standards for Python and SQL data pipelines.
globs: "**/*.py, **/*.sql"
alwaysApply: true
---
# Data Engineering Coding Standards
## Python
- **Type Hinting:** Mandatory for all pipeline functions (e.g., `df: pd.DataFrame -> None`).
- **Docstrings:** Use Google-style docstrings specifically describing the data schema expected.
- **Logging:** Use structured logging; never use `print()` for pipeline status.
## SQL
- **Keyword Casing:** Use UPPERCASE for all SQL keywords (SELECT, FROM, JOIN).
- **Aliases:** Always use explicit table aliases (e.g., `u.user_id` instead of `user_id`).
- **Joins:** Explicitly state the join type (e.g., `INNER JOIN`) rather than using commas.
