Can Hibernate work with MySQL's “ON DUPLICATE KEY UPDATE” syntax?

Question

MySQL supports an \"INSERT ... ON DUPLICATE KEY UPDATE ...\" syntax that allows you to \"blindly\" insert into the database, and fall back to updating the exist

Answer 1

If you are using Grails, I found this solution which did not require moving your Domain class into the JAVA world and using @SQLInsert annotations:

1. Create a custom Hibernate Configuration
2. Override the PersistentClass Map
3. Add your custom INSERT sql to the Persistent Classes you want using the ON DUPLICATE KEY.

For example, if you have a Domain object called Person and you want to INSERTS to be INSERT ON DUPLICATE KEY UPDATE you would create a configuration like so:

public class MyCustomConfiguration extends GrailsAnnotationConfiguration {

    public MyCustomConfiguration() {
        super();

        classes = new HashMap() {
            @Override
            public PersistentClass put(String key, PersistentClass value) {
                if (Person.class.getName().equalsIgnoreCase(key)) {
                    value.setCustomSQLInsert("insert into person (version, created_by_id, date_created, last_updated, name) values (?, ?, ?, ?, ?) on duplicate key update id=LAST_INSERT_ID(id)", true, ExecuteUpdateResultCheckStyle.COUNT);
                }
                return super.put(key, value);
            }
        };
    }

and add this as your Hibernate Configuration in DataSource.groovy:

dataSource {
    pooled = true
    driverClassName = "com.mysql.jdbc.Driver"
    configClass = 'MyCustomConfiguration'
}

Just a note to be careful using LAST_INSERT_ID, as this will NOT be set correctly if the UPDATE is executed instead of the INSERT unless you set it explicitly in the statement, e.g. id=LAST_INSERT_ID(id). I haven't checked where GORM gets the ID from, but I'm assuming somewhere it is using LAST_INSERT_ID.

Hope this helps.