Question

I am using Hibernate 3.x, MySQL 4.1.20 with Java 1.6. I am mapping a Hibernate Timestamp to a MySQL TIMESTAMP. So far so good. The problem is that MySQL stores the TIMESTAMP in seconds and discards the milliseconds and I now need millisecond precision. I figure I can use a BIGINT instead of TIMESTAMP in my table and convert the types in my Java code. I’m trying to figure out if there is a better way of doing this using hibernate, mysql, JDBC or some combination so I can still use date functions in my HSQL and/or SQL queries?

Answer 1

Also, look at creating a custom Hibernate Type implementation. Something along the lines of (psuedocode as I don’t have a handy environment to make it bulletproof):

public class CalendarBigIntType extends org.hibernate.type.CalendarType {     public Object get(ResultSet rs, String name) {         return cal = new GregorianCalendar(rs.getLong(name));     }     public void set(PreparedStatement stmt, Object value, int index) {         stmt.setParameter(index, ((Calendar) value).getTime());     } } 

Then, you’ll need to map your new object using a hibernate TypeDef and Type mappings. If you are using Hibernate annotations, it be along the lines of:

@TypeDef (name='bigIntCalendar', typeClass=CalendarBigIntType.class) @Entity public class MyEntity {     @Type(type='bigIntCalendar')     private Calendar myDate; }