Java 8 Time API with Hibernate using millisecond / nanosecond precision

Question

I have a very simple entity, that uses the new Java 8 Time API.

@Entity
@Table(name = "event")
public class Event {

    @Id
    @GeneratedValue
    @Column(name = "id")
    private long id;

    @Column(name = "time")
    private LocalDateTime time;

    // ommitted
}

To properly support conversion, im using

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-java8</artifactId>
    <version>5.1.0.Final</version>
</dependency>

However, records in the database are saved like 2018-05-12 22:24:31, which completely forgets the nanoseconds from LocalTime. I know that neither Timestamp nor Date can store nanoseconds, but i need at least millisecond precision. Is there any possibility to achieve this?

If relevant, I am using a MySQL database.

Answer 1

Change column type to

DATETIME(6) 

as curently your second fraction is lost due to integer nature of DATETIME Here you have MySQL documentation for that topic https://dev.mysql.com/doc/refman/8.0/en/fractional-seconds.html

Quoting

DATETIME(fsp)

The fsp value, if given, must be in the range 0 to 6. A value of 0 signifies that there is no fractional part. If omitted, the default precision is 0. (This differs from the standard SQL default of 6, for compatibility with previous MySQL versions.)