Can we use union in HQL?
Can we use union in HQL?
Unions are not supported by HQL.
What is native query in hibernate?
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.
What does hibernate Show_sql True means?
Setting the hibernate. show_sql to true tells hibernate to Write all SQL statements to console. This is an alternative to setting the log category org. Also, make sure that you don’t set the hibernate. show_sql programmatically to true when instancing your Configuration object.
What is 2nd level caching using Hibernate?
Hibernate second level cache uses a common cache for all the session object of a session factory. It is useful if you have multiple session objects from a session factory. It is global for all the session objects and not enabled by default. Different vendors have provided the implementation of Second Level Cache.
Which second level cache is better in hibernate?
Hibernate Second Level Cache
| Implementation | read-only | nonstrict-read-write |
|---|---|---|
| EH Cache | Yes | Yes |
| OS Cache | Yes | Yes |
| Swarm Cache | Yes | Yes |
| JBoss Cache | No | No |
Is there a way to use Union in hibernate?
I too looked into using UNION in HQL and couldn’t find a way around it. The odd thing was that I could find (in the Hibernate FAQ) that UNION is unsupported, bug reports pertaining to UNION marked ‘fixed’, newsgroups of people saying that the statements would be truncated at UNION, and other newsgroups of people reporting it works fine…
What is the Hibernate Query Language in HQL?
HQL: The Hibernate Query Language 14.1. Case Sensitivity 14.2. The from clause 14.3. Associations and joins 14.4. Forms of join syntax 14.5. Referring to identifier property 14.6. The select clause 14.7. Aggregate functions 14.8. Polymorphic queries 14.9. The where clause 14.10. Expressions 14.11. The order by clause 14.12. The group by clause
How does HQL DELETE statement in hibernate work?
HQL DELETE Statement DELETE removes the details of existing objects from the database. In-memory entities will not be updated to reflect changes resulting from DELETE statements. This also means that Hibernate’s cascade rules will not be followed for deletions carried out using HQL.
Which is the aggregate function in HQL Hibernate?
The aggregate functions available through HQL include the following: avg(property name): The average of a property’s value. count(property name or *): The number of times a property occurs in the results. max(property name): The maximum value of the property values.