All Articles & Tutorials
Explore practical guides, step-by-step masterclasses, and foundational definitions across AI, SQL, and data systems — written in plain, human English.
All articles
How to use retries and sensors in Apache Airflow, and when to skip Airflow
Retries buy time for flukes; sensors encode waiting with deadlines. Learn when to retry, how to sensor a late file without burning workers, and when Airflow is the…
How to define customer churn and retention so everyone agrees
Separate logo churn, revenue churn, gross retention, and net retention before you argue. Same word, different formulas, different decisions.
What to do when a coworker asks for access to your company’s production database
Match access to the question: sample, masked, or production read with an owner and an end date. Least privilege survives deadlines better than forever prod grants.
How to ask better data questions in meetings
Ask data questions that name the decision, window, segment, and success criteria. Use a question ladder so meetings end with an answerable next action.
How to build and test your first data models with dbt, a SQL tool
Turn layout into working models. Write your first staging and mart SQL, wire refs, add unique and not-null tests, and run a small build you can actually explain…
