How can I access multiple databases in hibernate?

You can connect two databases test1 and test2, retrieve data with only one hibernate with some tricks:

1. hibernate SQLQuery: just add database name with the table “select * from test1.table1”, “select * from test2.table2”
2. hibernate persistence: using the key schema in the hibernate mapping xml.

Can we have multiple SessionFactory in hibernate?

hibernate” package. Session factory is long live multithreaded object. Usually one session factory should be created for one database. When you have multiple databases in your application you should create multiple SessionFactory object.

How can I access multiple databases in spring boot?

Using multiple datasources with Spring Boot and Spring Data ? ⇄? ⇄ ?

1. Add an additional datasource configuration to your application.properties.
2. Set the SQL Dialect to “default” in your application.properties to let Spring autodetect the different SQL Dialects of each datasource.

Can we have multiple hibernate CFG XML?

Yes, you can.

What is lazy loading in hibernate?

Lazy loading is a fetching technique used for all the entities in Hibernate. It decides whether to load a child class object while loading the parent class object. Now, Hibernate can use lazy loading, which means it will load only the required classes, not all classes.

What is the use of SessionFactory in hibernate?

SessionFactory is an Interface which is present in org. hibernate package and it is used to create Session Object. It is immutable and thread-safe in nature. buildSessionFactory() method gathers the meta-data which is in the cfg Object.

Can I reuse the session in hibernate?

Obviously, you can. A hibernate session is more or less a database connection and a cache for database objects. And you can have multiple successive transactions in a single database connection. Whether you should or not is a matter of reusing objects from session.

Is hibernate SessionFactory Singleton?

To implement the Hibernate SessionFactory as a singleton, we create a separate class. Because this class is only responsible for making the Hibernate SessionFactory object as a singleton. Usually, we call such type of classes as utility classes.

What is the difference between @qualifier and @primary?

@Primary is also good if e.g. 95% of @Autowired wants a particular bean. That way, only the @Autowired that wants the other bean(s) need to specify @Qualifier . That way, you have primary beans that all autowired wants, and @Qualifier is only used to request an “alternate” bean.

How can we avoid lazy loading exception in Hibernate?

How to NOT fix the LazyInitializationException

1. Don’t use FetchType. EAGER.
2. Avoid the Open Session in View anti-pattern.
3. Don’t use hibernate.
4. Initializing associations with a LEFT JOIN FETCH clause.
5. Use a @NamedEntityGraph to initialize an association.
6. EntityGraph to initialize an association.
7. Using a DTO projection.

How to connect to multiple databases in hibernate Stack Overflow?

For mapping files, you just use cfg.addClass instead of addAnnotatedClass. Put the cfg.xml files in the root package in this case. Those will have the Oracle or MySQL dialect and connection information. It cannot be done using one hibernate configuration file.

Do you need to create a table in hibernate?

Before Hibernate, if database is changed for the project, we need to change the SQL query as well that leads to the maintenance problem. Hibernate framework provides the facility to create the tables of the database automatically. So there is no need to create tables in the database manually.

Where are the database configuration files in hibernate?

The details of those databases are configured in an XML file called hibernate.cfg.xml. This configuration files could be given any name and is usually placed in the root of your application class path. There are many configuration parameters available that makes the mapping of domain model to relational model easier.

Do you need to connect to more than one database server?

You may have different database servers where you need to establish connections using Hibernate ORM framework. ORM like Hibernate framework provides a number of significant advantages out of the box, such as, given below: During the development of a complex application, you may need to connect to more than one database server.