java - Hibernate: How to Map Composite Keys? -

i have table 3 composite keys. custom_id, patient_idpatient, service_provider_type_idservice_provider_type. current mapping below

<?xml version="1.0" encoding="utf-8"?> <!doctype hibernate-mapping public "-//hibernate/hibernate mapping dtd 3.0//en" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping>     <class name="beans.serviceprovider" table="service_provider" catalog="myglukose" optimistic-lock="version">         <id name="customid" type="string">             <column name="custom_id" not-null="true"/>         </id>         <many-to-one name="patient" class="beans.patient" fetch="select">             <column name="patient_idpatient" not-null="true"/>         </many-to-one>         <many-to-one name="serviceprovidertype" class="beans.serviceprovidertype" fetch="select">             <column name="service_provider_type_idservice_provider_type" not-null="true"/>         </many-to-one>         <property name="datecreated" type="timestamp">             <column name="date_created" length="19" />         </property>         <property name="lastupdated" type="timestamp">             <column name="last_updated" length="19" not-null="true" />         </property>     </class> </hibernate-mapping> 

my sql code

create table if not exists `xxx`.`service_provider` (   `custom_id` varchar(45) not null,   `patient_idpatient` int not null,   `service_provider_type_idservice_provider_type` int not null,   `date_created` timestamp null,   `last_updated` timestamp not null default current_timestamp,   index `fk_service_provider_patient1_idx` (`patient_idpatient` asc),   index `fk_service_provider_service_provider_type1_idx` (`service_provider_type_idservice_provider_type` asc),   primary key (`custom_id`, `patient_idpatient`, `service_provider_type_idservice_provider_type`),   constraint `fk_service_provider_patient1`     foreign key (`patient_idpatient`)     references `xxx`.`patient` (`idpatient`)     on delete cascade     on update no action,   constraint `fk_service_provider_service_provider_type1`     foreign key (`service_provider_type_idservice_provider_type`)     references `xxx`.`service_provider_type` (`idservice_provider_type`)     on delete no action     on update no action) engine = innodb; 

how can map these 3 composite keys in hibernate?

i know maybe have

<composite-id name="compid">    <key-property name="customid” column="custom_id" />    <key-property name="patientidpatient" column="patient_idpatient" />    <key-property name="serviceprovidertypeidserviceprovidertype" column="service_provider_type_idservice_provider_type" /> </composite-id> 

but not sure how apply xml mapping, whether should "just" add code, whether should remove first or make edits first. tried removing primary key mapping , relationship key mappings , adding above code, didnt work, ended multiple errors @ different times.

what correct way of mapping this? making edit existing xml code appreciated have complete picture of how should make work.