Type 1 vs Type 2 vs Type 3 Tradeoffs

The interview is not about knowing these types. It is about choosing between them under constraints. Each type is a tradeoff between history preservation, storage cost, query complexity, and pipeline complexity. Type 1: What to Say When History Doesn't Matter Your Type 1 answer: 'Type 1 overwrites the old value. I use it for attributes where nobody ever queries the historical value: name corrections, phone number updates, typo fixes. Applying Type 2 to a phone number creates rows nobody will ever query and bloats the dimension for no analytical benefit.' The key phrase is 'no analytical benefit.' That tells the interviewer you are choosing based on business value, not defaulting. Portland is gone. If any fact rows referenced revenue 'in Portland,' they now show 'Seattle.' This is either fi