03. Why is Data Modeling Important?

Key points about Data Modeling

• Data Organization: The organization of the data for your applications is extremely important and makes everyone's life easier.
• Use cases: Having a well thought out and organized data model is critical to how that data can later be used. Queries that could have been straightforward and simple might become complicated queries if data modeling isn't well thought out.
• Starting early: Thinking and planning ahead will help you be successful. This is not something you want to leave until the last minute.
• Iterative Process: Data modeling is not a fixed process. It is iterative as new requirements and data are introduced. Having flexibility will help as new information becomes available.

Example of Why Data Modeling is Important:

Let's take an example from Udacity. Here, a Udacity data engineer would help structure the data so it can be used by different people within Udacity for further analysis and also shared with the learner on the website. For instance, when we want to track the students' progress within a Nanodegree program, we want to aggregate data across students and projects within a Nanodegree. In a relational database, this requires the data to be structured in ways that each student's data is tracked across all Nanodegree programs that s/he has ever enrolled in. The data also needs to track the student's progress within each of those Nanodegree programs.

The data model is critical for accurately representing each data object. For instance, a data table would track a student's progress on project submissions, i.e., whether they passed or failed a specific rubric requirement. Furthermore, the data model should ensure that a student's progress is updated and aggregated to provide an indicator of whether the student passed all the rubric requirements and successfully finished the project. Data modeling is critical to track all of these pieces of data so the tables are speaking to each other, updating the tables correctly (e.g., updating a student's progress on a project submission), and meeting defined rules (e.g., project completed when all rubric requirements are passed).