# Dimensional Data Modeling: Building Slowly Changing Dimensions Day 2 Lecture

> We cover slowly changing dimensions and idempotent pipelines in this lecture! Enjoy!

- Web page: https://www.dataexpert.io/lesson/dimensional-data-modeling-day-2-lecture-yt-p736-l660
- Access: Free — no enrollment needed
- Length: 40 min video
- Skills: Data Modeling, ETL/ELT, Data Warehousing
- Academy: DataExpert.io Academy

## About this lesson

We cover slowly changing dimensions and idempotent pipelines in this lecture! Enjoy!

## Transcript excerpt

Welcome to dimensional data modeling Day 2 lecture. Today we're gonna be talking about slowly changing dimensions. So a slowly changing dimension is an attribute that drifts over time. For example, you can think of like your favorite food, you know, back in the early 2000s, my favorite food was lasagna, but then I kind of became more lactose intolerant, so I did not enjoy eating lasagna nearly as much. And then after I moved to the Bay Area, it became uh curry. So you could see like back in the day it was lasagna and then it changed to curry. So there are attributes and dimensions that. Change over time like that and we need to track the values. So it was like from 2000 to 2008, uh, it was lasagna and then it's been curry since then or whatever. You have like dimensions have a time frame with them slowly changing dimensions to other dimensions don't change, right? Like your birthday, your birthday is it's the same. It's not something that you can really change about your life, right? It's it is what it is. And so some dimensions change, some dimensions don't, and you need a model slowly changing dimensions the right way because if you don't, they impact this thing called item potency.