Forklaring ønskes

Jeg sidder og læser en bog men har svært ved at forstå hvad der menes med følgene:

CMP beans are defined in one-to-one correspondence to the tables of the
relational model. Thus, they’re too coarse grained; they may not take full
advantage of Java’s rich typing. In a sense, CMP forces your domain model
into first normal form.

Kan du forklare mig det ?