Difference between query, native query, named query and typed query [closed]

Question

What are the differences between a query, a native query, a named query and a typed query? Does the 'alone-standing' query even exist, or is it just an abbreviation? In my mind, a native Query is a query written in simple sql, whereas a named query relates to entities (hibernate-mapping). Can someone explain this briefly?

Potentiometer

Answer 1

Query

Query refers to JPQL/HQL query with syntax similar to SQL generally used to execute DML statements(CRUD operations).

In JPA, you can create a query using entityManager.createQuery(). You can look into API for more detail.

In Hibernate, you use session.createQuery()"

NativeQuery

Native query refers to actual sql queries (referring to actual database objects). These queries are the sql statements which can be directly executed in database using a database client.

JPA : entityManager.createNativeQuery() Hibernate (Non-JPA implementation): session.createSQLQuery()

NamedQuery

Similar to how the constant is defined. NamedQuery is the way you define your query by giving it a name. You could define this in mapping file in hibernate or also using annotations at entity level.

TypedQuery

TypedQuery gives you an option to mention the type of entity when you create a query and therefore any operation thereafter does not need an explicit cast to the intended type. Whereas the normal Query API does not return the exact type of Object you expect and you need to cast.

Robinson

Is there any performance, throughput, memory consumption, load app server differences between the different queries? I think that NamedQuery memory consumption is greater than query, but I can not say where is the limit of queries to opt in favor of one or another. Could you explain? thanks in advance – Worley

For lack of a better place to mention this, I'll add that one should be very careful converting Hibernate non-native queries to native queries, specifically w/respect to how null values are handled when returned from native queries. My team recently saw some weird SQLGrammarException: could not extract ResultSet and ORA-00932: inconsistent datatypes: expected NUMBER got BINARY errors when potential nulls were not accounted for. Maybe someone will stumble upon this comment and reach a resolution to their problem faster knowing this little gotcha. – Dotation

In createNativeQuery(), we can pass class type. That means our query result is mapped to the class which we mentioned? Can you please tell me how that works. – Aquila