Replacing *.hbm.xml files with @Annotations.

[JanErikR]

I have three java classes that are persisted using hibernate. I want to switch from using *.hbm.xml files to annotations on these classes. However the db has additional tables that are created by tags in hbm.xml. Is there a way to create these extra tables using annotations without having to create additional java classes.

 

 

One of the java classes that result in two tables in db:

 

public class Attribute {
private Long id;

private String name;

private String value;

private VocabularyElement parent;

// This map will result in its own table using the hbm.xml file listed below.
// What annotations can I use instead of the hbm.xml file?
private Map<String, String> extensionAttributes = new HashMap<String, String>();

// Constructors, getters, setters
// ...
}

 

 

hbm.xml file for the Attribute class:

 

<?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="com.tracetracker.mds.adm.domain.Attribute">

	<id name="id" access="field">
		<generator class="native"/>
	</id>

	<natural-id>
		<property name="name" access="field"/>
		<many-to-one name="parent" class="com.tracetracker.mds.adm.domain.VocabularyElement"/>		
	</natural-id>

	<property name="value" type="text"/>

	<!-- This tag creates the extra table. -->
	<map name="extensionAttributes" table="Attribute_Attr" 
			order-by="attr_name asc" lazy="false" access="field">
		<key column="id"/>
		<map-key column="attr_name" type="string"/>
		<element column="attr_value" type="string"/>
	</map>

</class>
</hibernate-mapping>

 

 

The resulting sql script:

 

create table Attribute (
id int8 not null,
name varchar(255) not null,
value text,
parent int8 not null,
primary key (id),
unique (name, parent)
);

create table Attribute_Attr (
id int8 not null,
attr_name varchar(255) not null,
attr_value varchar(255),
primary key (attr_name, id)
);

alter table Attribute add constraint FK7839CA7C7FB02B5A foreign key (parent) references VocabularyElement;
alter table Attribute_Attr add constraint FK4F4769F4A36A3D31 foreign key (id) references Attribute;

 

Any help is much apprecated.

[___]

Jeg ser av nicket ditt at du er norsk. Da foreslår jeg at du skriver innleggene dine på norsk.

 

Jeg håper du ikke har noe imot at jeg svarer på innlegget ditt med morsmålet mitt.

 

Hibernate er jo bare en av mange implementasjoner av JPA-spesifikasjonen, med litt ekstra krydder. Så du burde kunne mappe klassene dine mot databasen ved hjelp av JPA, og (forhåpentligvis) slippe noen Hibernate-spesifikke anmotasjoner.

 

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