About of Hibernate Session

Introduuction of Hibernate Session:-

Many object-oriented programming languages are having their syntaxes and libraries while on the other hand, the entire data which we store in the backend is based on the relational model having entirely different protocols and syntaxes to be followed. Hibernate is one of the middleware platforms to bridge this gap. This middleware application I called Object Relational Mapping (ORM). We have various ORM tools such as Hibernate, IBatis, Toplink, and many more. In this article, we will focus on Hibernate and its sessions.

Hibernate:-

It is the ORM tool used to link and map the items inside the utility layer to the database for the java programming language. It's far constructed to deal with the impedance mismatch between a normal programming language and the relational database. It's miles free of fee software with a GNU license, which may be easily downloaded from the internet.

Hibernate is an extension of the JAVA persistence API. It supports the Hibernate Query language (HQL). Hibernates major role is to link the JAVA objects and classes to the database classes via XML structure or JAVA annotations. Similarly, the datatypes of JAVA should be matched with the database’s datatypes so that there is miscommunication between two different systems. Hibernate can be used to extract the data using queries. It can generate SQL calls and thereby mitigate manual errors and developers’ work. There are different inbuilt functions in hibernate for ease of use like:

load(), update (), get (), merge() : If we are sure that object exist then we use this function to load the hibernate object otherwise we use get() function. Update and merge functions are used to update the database records based on the current sessions that already exist or we are fresh sessions for the transaction. There are many more functions like this to support hibernate.

Hibernate Session:-

It is a runtime interface among software and hibernates which is created on-demand. In other words, it affords connectivity among your utility and database. It offers diverse features inclusive of creating, deleting, getting, replace to operate on the database using the usage of consultation strategies that exist in four states namely: brief, persistent, and indifferent, eliminated.

Hibernate has been created to serve this reason. It easily connects the database to java language regardless of any database. It comes with bendy features and as a consequence selling flexibility of managing records over one-of-a-kind platforms.

Methods of Hibernate Session:-

1. Save(): Save() method generates the primary key and inserts the record in the database. It is similar to the persist() method in JPA but it behaves differently in a detached instance by creating the duplicate record upon database commit.
2. Update():Update() is used to update the existing database record. It returns an exception if the record is not found or called in a transient instance.
3. saveOrUpdate(): It saves or updates the database based on the entity passed. It does not return an exception in the transient state but it makes the state to persistent during a database operation.
4. merge(): Values from a detached entity are updated to the database when the merge() is used by changing the detached entity to the persistent state.
5. delete(): Delete method works in persistent mode to remove the entity from the database. An exception is returned if no record is found in the database.

How to Create a Hibernate Session:-

To create a hibernate session, we have to load hibernate dependencies in the library of the tool which you are using along with the database connector. Once, these libraries are loaded we can establish the connection by creating a session using the session factory.

Let’s assume we have a table with two columns: Employee Id and Employee Name which should be updated.

Code Snippet:

import.org.hibernate.session // This way we hall import the hibernate class in the main program.

public class test class hibernate //declaration of the class.

{

public static void main( string[] args ) //The program;s main execution shall start from here.

{

testprogram = new program(); // Here the class is objectified and then this object is used as a reference to send the values like employee name and employee ID which needs to be imported into the database table.

program.setEmpId(101);

program.setEmpName(“User1”);

Configuration con = new Config().configure().addAnnotedClass testclasshibernate;

// Create session factory using configuration

SessionFactory sf1 = con.buildsessionfactory();

// Open session method gives the object of session.

Session s1 = sf.OpenSession();

// Opening Transaction

Transaction t1 = session.beginTransaction();

session.save(testprogram);

tx.commit();

}

}

Advantages of the Hibernate Session:-

• Hibernate session complies with the ACID(Atomicity, Consistency, Isolation, and Durability) properties of the database.
• Its object mapping is consistent and thus reduces a lot of potential bugs and loopholes from the code.
• It is database-independent so even if there is any database like MySQL or oracle this software can be used.
• There is no need to know the SQL only basic knowledge of it should help you in understanding how it works.
• Easy to create associations and a lot of guidance present over the net. Java being used widely with an association to a database over the net can c=make the most use of this software if used wisely.
• Minimal code changes when there are any changes to tables since everything is handled via class and objects. Most of the code and functionalities are generic thus making it more worthy for use in applications which has a lot of dependency over transactional data.
• Hibernate supports multilevel caching thereby improving the coding efficiency.