As you may have garnered from this book’s table of contents, the persistence layer of Grails is a critical part of the picture. In Chapter 3 you were given a surface-level understanding of what domain classes are and how they map onto the underlying database. In this chapter you’ll plunge headfirst into the inner workings of GORM.
As a starting point, you’ll learn about the basic persistence operations involved in reading and writing objects from a database. After going through the basics, you’ll then be taken through the semantics of GORM, including as many corner cases and surprises as we’re able to fit into a single chapter. ...