Update README.md

Author: AnghelLeonard

README.md

@@ -4019,3 +4019,17 @@ From Openjdk JEP359:
 Define the `AuthorDto` as:
 
 `public record AuthorDto(String name, int age) implements Serializable {}`
+
+----------------------------------------------------------------------------------------------------------------------- 
+
+274. **[How To Fetch DTO Via JDK14 Records And A Custom `ResultTransformer`](https://github.com/AnghelLeonard/Hibernate-SpringBoot/tree/master/HibernateSpringBootDtoRecordResultTransformer)**
+  
+**Description:** Fetching more *read-only* data than needed is prone to performance penalties. Using DTO allows us to extract only the needed data. Sometimes, we need to fetch a DTO made of a subset of properties (columns) from a parent-child association. For such cases, we can use SQL `JOIN` that can pick up the desired columns from the involved tables. But, `JOIN` returns an `List<Object[]>` and most probably you will need to represent it as a `List<ParentDto>`, where a `ParentDto` instance has a `List<ChildDto>`. For such cases, we can rely on a custom Hibernate `ResultTransformer`. This application is a sample of writing a custom `ResultTransformer`.
+
+As DTO, we rely on JDK 14 Records. From Openjdk JEP359:
+
+*Records provide a compact syntax for declaring classes which are transparent holders for shallowly immutable data.*
+
+**Key points:**
+- define the Java Records as `AuthorDto` and `BookDto`
+- implement the `ResultTransformer` interface