How do UPSERT and MERGE work in Oracle, SQL Server, PostgreSQL and MySQL

Introduction

Last week, Burkhard Graves asked me to answer the following StackOverflow question:

And, since he wasn’t convinced about my answer:

I decided to turn it into a dedicated article and explain how UPSERT and MERGE work in the top 4 most common relational database systems: Oracle, SQL Server, PostgreSQL, and MySQL.

Continue reading “How do UPSERT and MERGE work in Oracle, SQL Server, PostgreSQL and MySQL”

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How to optimize the merge operation using update while batching with JPA and Hibernate

Introduction

One of my readers has recently asked me about optimizing the merge entity state transition, and, because this is a great question, I decided to turn it into a blog post.

In this article, you are going to see a shortcoming of the merge entity state transition and how you can deal with it using Hibernate.

Continue reading “How to optimize the merge operation using update while batching with JPA and Hibernate”