Validating form fields with ajax
A unidirectional relationship has only an owning side.
The owning side of a relationship determines how the Persistence runtime makes updates to the relationship in the database.
An entity is a lightweight persistence domain object.
Typically, an entity represents a table in a relational database, and each entity instance corresponds to a row in that table.
Bean Validation constraints are applied to the persistent fields or properties of persistent classes.
The Java API for Java Beans Validation (Bean Validation) provides a mechanism for validating application data.
Bean Validation is integrated into the Java EE containers, allowing the same validation logic to be used in any of the tiers of an enterprise application.
Composite primary keys are used when a primary key consists of more than one attribute, which corresponds to a set of single persistent properties or fields.
Composite primary keys must be defined in a primary key class.
If the class uses property access, apply the constraints on the getter methods.