14.2. The from clause

The simplest possible Hibernate query is of the form:
from eg.Cat
which simply returns all instances of the class eg.Cat. We don't usually need to qualify the class name, since auto-import is the default. So we almost always just write:
from Cat
Most of the time, you will need to assign an alias, since you will want to refer to the Cat in other parts of the query.
from Cat as cat
This query assigns the alias cat to Cat instances, so we could use that alias later in the query. The as keyword is optional; we could also write:
from Cat cat
Multiple classes may appear, resulting in a cartesian product or "cross" join.
from Formula, Parameter
from Formula as form, Parameter as param
It is considered good practice to name query aliases using an initial lowercase, consistent with Java naming standards for local variables (eg. domesticCat).