How-to articles, tricks, and solutions about HIBERNATE

If you are trying to execute a query using Hibernate and are getting an error saying "could not extract ResultSet," it could be due to a few different issues:

In the Java Persistence API (JPA), the FetchType enum is used to specify the strategy for fetching data from the database.

To show the real SQL generated by Hibernate, you can enable the show_sql property in the Hibernate configuration file (hibernate.cfg.xml).

If you are using Hibernate and you see the error "MultipleBagFetchException: cannot simultaneously fetch multiple bags", it means that you are trying to fetch multiple collections of an entity using a single Hibernate query.

To log SQL statements in Spring Boot, you can configure the logging level of the org.hibernate.SQL logger to DEBUG or TRACE.

The LazyInitializationException in Hibernate is thrown when an object that has been loaded with a "lazy" fetch type is accessed outside of a valid session.

To print a Hibernate query string with parameter values, you can use the toString() method of the Query interface.

The "failed to lazily initialize a collection of role" exception in Hibernate is thrown when you try to access an uninitialized collection from a Hibernate entity when the entity is in a detached state.

In a JPA entity mapping, the @JoinColumn annotation is used to specify the foreign key column for a many-to-one or one-to-one relationship.

The hbm2ddl.auto configuration property in Hibernate determines the mode in which Hibernate should operate when it comes to generating the database schema. The possible values for this property are:

Java Persistence API (JPA) is a specification for object-relational mapping (ORM) in Java.