Overview
Using a view in a database is not popular nowadays as it was before especially with microservice architecture.
However, you could face it in a project.
A view is a virtual table based on the result-set of an SQL statement.
In the post, we are going to implement an entity for a view with the help of the Hibernate.
Entity for a view with the help of the Hibernate
Suppose, we have a view in a database with the “EXAMPLE” name.
Then, an entity for the view may look like this (I omit all properties except ID, equals()/hashCode() for brevity):
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@Entity
@Immutable
@Subselect("SELECT * FROM EXAMPLE")
class MyEntity(
@Id
@Column(name = "ID"),
val id: Long = 0,
...
) {
// equals()
// hashCode()
}
@Entity - it declares the class as an entity (i.e. a persistent POJO class).
@Immutable - it means read-only.
@Subselect - it means to map an immutable and read-only entity to a given SQL select expression.
Conclusion
We have described how to implement an entity for a view with the help of the Hibernate.
Links:
http://lifeinide.com/post/2017-08-22-views-in-hibernate/
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