How does a spreadsheet become a highly-tuned set of tables in a relational system? There are rules for this - the rules of normalization - which is an essential skill for any developer working with data
There is an established way to design a transactional database: following the rules of normalization. This is the process of essentially turning a single, large spreadsheet into a set of related tables.
Transactional systems can back our applications, but analytical systems power decision making. Data warehouses and data marts store the data and OLAP systems provide the analysis infrastructure.