Hibernate what is the difference between merge and update

So if we want to update present object with previous object changes we have to use merge method. Merge method will merge changes of both states of object and will save in database. Merge: if you want to save your modifications at any time with out knowing about the state of an session, then use merge in hibernate.

Dinesh Rajput is the chief editor of a website Dineshonjava, a technical blog dedicated to the Spring and Java technologies. It has a series of articles related to Java technologies. Dinesh has been a Spring enthusiast since and is a Pivotal Certified Spring Professional, an author of a book Spring 5 Design Pattern, and a blogger. He has more than 10 years of experience with different aspects of Spring and Java design and development. He is currently working as a technology manager at a leading product and web development company.

Ltd and was the first developer in his previous company, Paytm. Dinesh is passionate about the latest Java technologies and loves to write technical blogs related to it. Share a word. About the Author: chandrashekhar. Founder of onlinetutorialspoint. Follow him on twitter and facebook for latest updates. Gaurav Pant September 23, at am - Reply. Best explanation I have ever read.. Very clearly explained the difference. Karthi December 3, at am - Reply.

Mandeep June 1, at pm - Reply. In reply to Mandeep. Prahalad December 13, at pm - Reply. Eshwar September 14, at am - Reply. Leave A Comment Cancel reply Comment. So if we want to update present object with previous object changes we have to use merge method. Merge method will merge changes of both states of object and will save in database. Update: If we are dealing with any object in same session we should use update or saveOrUpdate method.

Hope you will get point. But merge method can save your modifications at any time with out having the knowledge about the state of session.

After that we changed the name property of that detached object. Now if we call update we will get exception because before reattachment, another instance that represents the same database row has already been loaded into the persistence context of that Session and Hibernate will get confused which object represents the current state. However, for merge into updatedMe object, changes of me object will be merged and will finally be saved into the database.

Hope this clarifies the doubts! Have a great day ahead!!