Big SQL Energy Beginner Course: Lesson 26 Data Dictionaries
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Hi BDEs! Welcome to Lesson 26 of the free Big SQL Energy Beginner Course⚡️ Today we’re learning about Data Dictionaries in SQL!
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Lesson 26: Data Dictionaries
Today we’re talking about one of the sexist parts of Data Analytics: Data Documentation 🥵🔥😮💨
🔗Grab the Big SQL Energy Beginner Data Dictionary here
You might be laughing, but I promise you: data documentation is a huge luxury in the real world, so if you’re lucky enough to get it, be grateful. The real world can be really messy and a lot times, there’s no documentation for databases and tables. It can be really challenging to find what you need and understand what each table contains. More importantly, it can be really challenging to understand how all the tables connect together which is necessary knowledge for joining— which we’ll learn a little later!
Data dictionaries are exactly what they sounds like. They’re a centralized source of truth within an organization where all the information about the data is stored. It’s a guide on what tables are available, what’s in each table, and what you can expect from each column. Sometimes companies use fancy tools for data documentation or even something as simple as Confluence or Excel sheets. It really depends on the size of the company and the size of the investment in data documentation! I’ve worked at mostly startups, so to even get an Excel sheet was an exciting thing for me LOL! Many data sources (like CRMs) that are ETLed (Extract Transform Load) into your database may even have their own data documentation online you can use.
Data dictionaries will usually have some or all of the following information:
Column names
Data types: each column’s data type
Field description: a definition of the column
Allowed Values: what type of values can be in the column (ex. closed list of values, strings of length 2, etc.)
Data source or lineage: where the data comes from and how it got there, any transformations or modifications it has
The team that owns the data: who you can reach out to if you need help of updates
Other notes and useful info!
Remember, not all companies will even have data dictionaries at all, but it could be worth advocating for within your company for the most-used tables, especially if you’re training someone new soon. Having a single source of truth and a place to look up columns can be really useful for someone.
Data documentation isn’t the most sexiest thing to do, but it’s the boring stuff that can be the most important long term! See you in the next lesson!
If you’ve enjoyed the free BEGINNER Big SQL Energy course, grab my intermediate course. There are no deadlines or timelines for this course— you start and take as long as you want. It will take your beginner skills to the next level and get you ready to ace your interviews. DM me or email me at courses@bdeanalytics.com if you have questions on the intermediate course!
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