Asked by: Estanis Randleasked in category: General Last Updated: 5th June, 2020
Can we create JPA entity without @ID?
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Accordingly, is ID mandatory in hibernate?
Yes, hibernate requires an Id. Sometimes if you are dealing with a legacy database that for whatever reason does not have a key, you can define the key in Hibernate to be a composite key of all the columns for example, as this will be guaranteed to be unique.
Similarly, can we create entity in hibernate without primary key? Its not juts Hibernate - a relational datamodel require primary keys. So what you've got is a broken data model because without a primary key it can't be relational, and this is why its difficult to use with an ORM. You can fix this by defining a surrogate key.
Subsequently, one may also ask, what is a JPA entity?
A JPA entity class is a POJO (Plain Old Java Object) class, i.e. an ordinary Java class that is marked (annotated) as having the ability to represent objects in the database. Conceptually this is similar to serializable classes, which are marked as having the ability to be serialized.
How is composite key defined in JPA entity?
A composite primary key – also called a composite key – is a combination of two or more columns to form a primary key for a table.
2. Composite Primary Keys
- The composite primary key class must be public.
- It must have a no-arg constructor.
- It must define equals() and hashCode() methods.
- It must be Serializable.