In this course we saw the document model for patients, visits, medication, payment etc. All these transactions are entered in to a computer by front office receptionists and nurses. How does this data gets into a SQL server? Where does the data they entered go? Is it stored in an excel file then retrieved by IT and written to a SQL server?
Are you referring to the “MongoDB in 5 minutes” lesson or the “ACID with Transactions and Documents” lesson?
In the “MongoDB in 5 minutes” lesson, Eliot simply wants to highlight the point that a relational database could be stored in Excel as an alternative to a SQL server due to the tabular nature of the data.
If you have only one table of data, it maps well to a spreadsheet. However, as you pointed out, if many people need to write in the spreadsheet at the same time, it is not a good solution and this is why people use database products.