Data Dictionary

Finally, we need to know what data our system is actually going to store. This could be in a Pandas dataframe, a dictionary, or just whatever format it comes in from your API. We need to know this before we start programming because we need a sense of what rules the data will need to follow.

Otherwise, your shall we say... less than tech savvy users will cause error after error after error. Never underestimate an end user - they can and will break the rules!

So, let's be specific with the data types and validation so we know how to stop this.

Example

Here's a data dictionary for storing rock data in the Rock Collection Program:

Variable	Data Type	Format for Display	Size in Bytes	Size for Display	Description	Example	Validation
name	String	Text	50	50	The name of the rock/mineral	"Granite"	Must be a non-empty string
hardness	Integer	Whole number	4	2	hardness scale value	6	1 ≤ hardness ≤ 10
composition	String	Text	100	100	Main mineral components	"Quartz, Feldspar"	Must be a valid string
colour	String	Text	20	20	Common rock colors	"Grey"	Must be a valid colour name
location_found	String	Text	20	100	Place where the rock was found	"Yosemite, USA"	Must be a valid location

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Data Dictionaries