I also maintain an agile database books page which overviews many books you will find interesting. Verb-type entities represent actions and interactions between the noun-type entities.
This is known as a deletion anomaly. Data normalization helps you design new databases to meet these goals or to test databases to see whether they meet the goals.
For example, to track an inventory item that may come from two possible sources, an inventory record may contain fields for Vendor Code 1 and Vendor Code 2. You must do the same separation with the BilledTo attribute. After you designate a pkey, table AllData will be in 1NF.
Ideally, each phase in the life cycle can be checked for correctness before moving on to the next phase.
The data items that make up this attribute are unique; no two data item values are the same. Same with genre.