![]() What is use of Hibernate Session merge() call? However one of the major disadvantages of Named query is that it’s hard to debug, because we need to find out the location where it’s defined. Hibernate Named Query is global, means once defined it can be used throughout the application. ![]() Hibernate Named Query syntax is checked when the hibernate session factory is created, thus making the application fail fast in case of any error in the named queries. Hibernate Named Query helps us in grouping queries at a central location rather than letting them scattered all over the code. What are the benefits of Named SQL Query? However hibernate provides methods through which we can delete selected objects from the cache or clear the cache completely.Īny object cached in a session will not be visible to other sessions and when the session is closed, all the cached objects will also be lost. Hibernate first level cache is enabled by default and there is no way to disable it. Hibernate first level cache is associated with the Session object. The idea behind cache is to reduce the number of database queries, hence reducing the throughput time of the application. Hibernate Cache can be very useful in gaining fast application performance if used correctly. What is hibernate caching? Explain Hibernate first level cache?Īs the name suggests, hibernate caches query data to make our application faster. Some other important parts of hibernate configuration file is Dialect information, so that hibernate knows the database type and mapping file or class details. We provide database credentials or JNDI resource information in the hibernate configuration xml file. Hibernate configuration file contains database specific configurations and used to initialize SessionFactory. The state of a transient or detached instance may also be made persistent as a new persistent instance by calling merge(). Detached instances may be made persistent by calling update(), saveOrUpdate(), lock() or replicate(). ![]() Any instance returned by a get() or load() method is persistent.ĭetached: When an object is previously persistent but not associated with any session, it’s in detached state. Persistent: When an object is associated with a unique session, it’s in persistent state. Persistent instances may be made transient by calling delete(). Transient instances may be made persistent by calling save(), persist() or saveOrUpdate(). ![]() Transient: When an object is never persisted or associated with any session, it’s in transient state. ![]() What are different states of an entity bean? An entity bean instance can exist is one of the three states. There are five collection types in hibernate used for one-to-many relationship mappings. What are the collection types in Hibernate? This lets the users to develop persistent classes following object-oriented principles such as association, inheritance, polymorphism, composition, and collections. Hibernate is a powerful, high performance object/relational persistence and query service. Following are some of the most frequently asked Hibernate interview questions in the interview, here are the answers for them. ![]()
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