auto increment « Insert « JPA Q&A

1. how to use em.merge() to insert OR update for jpa entities if primary key is generated by database?

I have an JPA entity like this:

@Table(name = "category")
public class Category implements Serializable {
    private static final long serialVersionUID = 1L;


2. How to auto increment data on new record insertion

I would like to add a user defined column which will auto increment on new record insertion, how should I do this? so that it runs on h2, mysql

@Entity public class ...

3. last inserted unique id from auto increment in mysql

Say in an order table, the id is unique and auto incremented by mysql, so when an Order object is prepared for saving, no id is set. How can one get the last inserted (mysql generated) unique id from the table which will be set to the Order object without resorting back to JDBC. This id will then be used to ...

4. insert into table that contains auto increment column

Hello; i have a table that contains thrree columns reviewId | reviewerName |reviewerId whare reviewId is primary key and auto_increment. i had POJO class Code: package com.ahs.da.hib; /** * Review entity. * * @author MyEclipse Persistence Tools */ public class Review implements { // Fields private Integer reviewId; private String reviewName; ...