SqlServer convert to mySql5.5 ,jpa @GeneratedValue does not work

Question

When I convert my database from Sql Server to MySql, the JPA @GeneratedValue does not work, return null, the code like this:

@Id
@GeneratedValue
@Column(name = "ID", unique = true, nullable = false)
public Integer getId() {
    return id;
}

Should I change some properties?

Dharmvir Tiwari · Accepted Answer · 2016-05-23 11:16:50Z

1

You need to explicitly specify the generation strategy

@GeneratedValue(strategy = GenerationType.IDENTITY)

Basically there are 4 types of generation strategy:

Auto
Identity
Sequence
Table

answered May 23, 2016 at 11:16

Dharmvir Tiwari

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3 Comments

W.Money Over a year ago

@GeneratedValue have default value(strategy = GenerationType.AUTO) ,when the database is MySql ,the value is AUTO_INCREMENT,isn't that?

Neil Stockton Over a year ago

AUTO actually means "the JPA provider chooses" ... not AUTO_INCREMENT. So you cannot bank on any particular one being used unless you choose IDENTITY, SEQUENCE or TABLE.

Dharmvir Tiwari Over a year ago

As already mentioned by @NeilStockton. GenerationType.AUTO makes JPA Provider to decide on the generation strategy, it may choose Table based or sequence based strategy so it is good that the data source you have has high privilege (It has to create a table or sequence and these are high privilege operations often restricted)

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