Something sort of like this already exists shipped with Excel in the form of Power Pivot, which stores data in an embedded database inside the Excel workbook, a

Something sort of like this already exists shipped with Excel in the form of Power Pivot, which stores data in an embedded database inside the Excel workbook, and is supposed to scale up to 2GB and hundreds of millions of rows. https://support.microsoft.com/en-us/office/power-pivot-powerful-data-analysis-and-data-modeling-in-excel-a9c2c6e2-cc49-4976-a7d7-40896795d045 https://support.microsoft.com/en-us/office/power-pivot-power... As you might see from that link it's semi-integrated with the Excel interface, but the differences in the underlying model show through in some ways (like not being able to edit individual cells or use VBA)