Develop Reference

'Repeated column in mapping' when mapping a class to an existing list of objects

I'm adding ResourcePermission to the object Report. Each Query object can have in a one-to-one relationship. A Query extends Resource and has ResourcePermission's in a one-to-many (one Query to many Permissions).
I need to add the same property to the Report object associated with the Query because it can have different permissions. When I add the list and the map the one Query to many Permission relationship I get
Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: com.bio.ResourcePermission column: resource_id (should be mapped with insert="false" update="false")
Which I am not understanding why, the Report does not extend Query or Resource and therefore it isn't mapped twice. Can a table just not be the many for multiple one-to-many relationships?
<class name="com.bio.Report" table="REPORT">
<id name="id" type="long" column="id">
<generator class="foreign">
<param name="property">query</param>
</generator>
</id>
<property name="name" column="name"/>
<!--Trying to add this list mapping breaks it-->
<bag name="permissions" table="RESOURCE_PERMISSION">
<key column="resource_id" not-null="true"/>
<one-to-many class="com.bio.ResourcePermission"/>
</bag>
<!-- This query extends Resource-->
<one-to-one name="query" class="com.bio.Query" />
</class>
This is the original item that had ResourcePermissions
<class name="com.bio.Resource" table="RESOURCE">
<id name="id" type="long" column="id">
<generator class="native">
<param name="sequence">SEQ_RESOURCE_AUTO</param>
</generator>
</id>
<bag name="permissions" table="RESOURCE_PERMISSION" lazy="true" batch-size="50" cascade="all-delete-orphan">
<key column="resource_id" not-null="true"/>
<one-to-many class="com.bio.ResourcePermission"/>
</bag>
</class>
The Permission mapping
<class name="com.bio.ResourcePermission" table="RESOURCE_PERMISSION">
<id name="id" type="long" column="id">
<generator class="native">
<param name="sequence">SEQ_RES_PERM_AUTO</param>
</generator>
</id>
<property name="canEdit" column="edit"/>
<property name="canView" column="can_view"/>
<property name="canRun" column="run"/>
<property name="everyone" column="everyone"/>
</class>

I had to set inverse="true" on the Report mapping since the ReportPermission will be responsible for the relationship.
<bag name="permissions" table="RESOURCE_PERMISSION" inverse="true">
<key column="resource_id" not-null="true"/>
<one-to-many class="com.bio.ResourcePermission"/>
</bag>

Hibernate make same aliases for different joins

Suppose, we have 3 entity
<class name="AEntity" table="A" abstract="true">
<id name="id">
<column name="ID"/>
</id>
<joined-subclass table="Aa" name="AaEntity">
<key column="key"/>
<many-to-one name="b" class="BEntity">
<column name="B_ID"/>
</many-to-one>
</joined-subclass>
<joined-subclass table="Ab" name="AbEntity">
<key column="key"/>
<many-to-one name="b" class="BEntity">
<column name="B_ID"/>
</many-to-one>
</joined-subclass>
</class>
<hibernate-mapping>
<class name="Parent" table="parent">
<id name="id">
<column name="ID"/>
</id>
<many-to-one name="a" class="AEntity">
<column name="a_ID" />
</many-to-one>
</class>
</hibernate-mapping>
<hibernate-mapping>
<class name="BEntity" table="B">
<id name="id">
<column name="ID"/>
</id>
</class>
</hibernate-mapping>
Then, we make criteria request
Criteria criteria = session.createCriteria(Parent.class);
criteria.createAlias("a","a");
criteria.createAlias("a.b","b");
criteria.list();
And get next sql
select this_.ID as ID1_5_3_,
this_.a_ID as a2_5_3_,
a1_.ID as ID1_2_0_,
a1_.B_ID as B2_2_0_,
a1_1_.B_ID as B2_0_0_,
a1_2_.B_ID as B2_1_0_,
case when a1_1_.key is not null then 1 when a1_2_.key is not null then 2 when a1_.ID is not null then 0 end as clazz_0_,
b2_.ID as ID1_3_1_,
b2_.C_ID as C2_3_1_,
b2_.ID as ID1_3_2_,
b2_.C_ID as C2_3_2_
from parent this_
inner join A a1_ on this_.a_ID=a1_.ID
left outer join Aa a1_1_ on a1_.ID=a1_1_.key
left outer join Ab a1_2_ on a1_.ID=a1_2_.key
inner join B b2_ on a1_1_.B_ID=b2_.ID
inner join B b2_ on a1_2_.B_ID=b2_.ID
We can see that B table joins two times and have same name b2_. Is it bug? And how make two joins but with different name of B table.
Okay?

Try aliases like
Criteria criteria = session.createCriteria(Parent.class, "parent");
criteria.createAlias("parent.a","a");
criteria.createAlias("parent.a.AaEntity.b","aab");
criteria.createAlias("parent.a.AbEntity.b","abb");
criteria.list();
PS: I have not tested this and it may not work as it is, but this will give you an idea on how to force the alias names.

Regarding one to one mapping in hibernate

I am a new bie to the world of hibernate could you please advise , I was going through one to one relationship in Hibernate,
As per my analysis , one to one hibernate relationships can be established by three ways..
1)Through Join concept
2)Same primary key in both the tables
3)Primary key and foriegn key relationship in both the tables
Please advise , the above three ways to achieve the one to one mapping is correct or I am missing something then please advise, and also please advise that the below hbm mapping files that I am using are correct one.if not then please advise.
1) Through Join concept :-
One way to achieve to one to one relationship is by joining concept , following xml is being used for that
<hibernate-mapping>
<class name="mypack.Person" table="person21">
<id name="personId" type="int">
<generator class="increment">
</generator>
</id>
<property name="name"/>
<join table="personAddress">
<key column="personId"/>
<many-to-one name="address" class="mypack.Address" column="addressId" unique="true" cascade="all"/>
</join>
</class>
<class name="mypack.Address" table="address21">
<id name="id" column="addressId" type="int">
<generator class="increment"/>
</id>
<property name="city"/>
<property name="state"/>
</class>
</hibernate-mapping>
2) Same primary key in both the tables :-
Using same primary key in both the tables , following hbm is being used for that
<class name="mypack.Address" table="address31">
<id name="id" column="addressId" type="int">
<generator class="increment"/>
</id>
<property name="city"/>
<property name="state"/>
</class>
<class name="mypack.Person" table="person31">
<id name="personId" type="int">
<generator class="foreign">
<param name="property">address</param>
</generator>
</id>
<property name="name"/>
<one-to-one name="address" class="mypack.Address"/>
</class>
</hibernate-mapping>
3)Primary key and foriegn key relationship in both the tables :-
Primary key in one table and foriegn key in another table. below is the hbm for this
<hibernate-mapping>
<class name="mypack.Person">
<id name="personId" type="int">
<generator class="increment"/>
</id>
<property name="name"/>
<many-to-one name="address" class="mypack.Address" column="addressId" unique="true" cascade="all"/>
</class>
<class name="mypack.Address">
<id name="id" column="addressId" type="int">
<generator class="increment"/>
</id>
<property name="city"/>
<property name="state"/>
</class>
</hibernate-mapping>
folks please advise.

I really think that join table is overkill here for a one-to-one mapping. For the other 2 solutions, please take a look at the following Hibernate documentation, everything is explained : http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/mapping.html#mapping-declaration-onetoone.
For your second mapping (primary key association), both entities need to define a one-to-one mapping and one side of the relation also needs to specify the attribute constrained="true".
This is how I would write your second mapping :
<class name="mypack.Person" table="PERSONS">
<id name="id" type="int" column="PERSON_ID">
<generator class="increment"/>
</id>
<property name="name" type="string" column="NAME"/>
<one-to-one name="address" class="mypack.Address" cascade="all"/>
</class>
<class name="mypack.Address" table="ADDRESSES">
<id name="id" type="int" column="ADDRESS_ID">
<generator class="foreign">
<param name="property">address</param>
</generator>
</id>
<property name="city" type="string" column="CITY"/>
<property name="state" type="string" column="STATE"/>
<one-to-one name="person" class="mypack.Person" constrained="true"/>
</class>

Map a one-to-zero association with hibernate

Could somebody explain me how to map a one-to-zero association with hibernate (using mapping xml files NOT annotations)?
These are the rules:
A Menu can have 0 or 1 Area associated.
An Area belongs to a Menu. (Or, if it is easier for you to modelize it: An Area can have 0 or 1 Menu associated).
Here are the desired TABLES (I want to use foreign keys):
TABLE MENU:
ID
NAME
FKID_AREA
TABLE AREA:
ID
NAME
FKID_MENU
Thanks!

You should remove the FKID_AREA from the MENU table, because it's not needed (and is even a problem, since it's redendant with AREA.FKID_MENU).
For the rest, this is described in the Hibernate documentation on bidirectional one-to-one association mappings:
<class name="Area">
<id name="id" column="ID">
<generator class="native"/>
</id>
<many-to-one name="menu"
column="FKID_MENU"
unique="true"
not-null="false"/>
</class>
<class name="Menu">
<id name="id" column="ID">
<generator class="native"/>
</id>
<one-to-one name="area"
property-ref="menu"/>
</class>

You should remove FKID_MENU from AREA table. As per your description, your hbm mapping would be below
<class name="Menu">
<id name="id" column="ID">
<generator class="native"/>
</id>
<property name="name" cloumn="name"/>
<many-to-one name="area" column="FKID_AREA" class="Area"/>
</class>
<class name="Area">
<id name="id" column="ID">
<generator class="native"/>
</id>
<property name="name" cloumn="name"/>
</class>

Hibernate: how to get an inversely joined entity (one-to-one)

I have a table Project with fields
ID
PROJECT_BASELINE_ATTRIBUTES_ID (FK for table PROJECT_BASELINE_ATTR)
This table has the following mapping
<hibernate-mapping package="com.initech.db.model">
<class name="com.initech.db.model.Project" table="PROJECT">
<id name="id" column="id" type="java.lang.Long">
<meta attribute="use-in-tostring">true</meta>
<generator class="sequence">
<param name="sequence">PROJECT_ID_SEQ</param>
</generator>
</id>
<many-to-one name="projectBaselineAttributes" column="PROJECT_BASELINE_ATTRIBUTES_ID" class="com.initech.db.model.ProjectBaselineAttributes" cascade="all" not-null="true">
<meta attribute="use-in-tostring">true</meta>
</many-to-one>^
</class>
</hibernate-mapping>
The respective Project.java class has the fields
private Long id;
private ProjectBaselineAttributes projectBaselineAttributes;
Furthermore, I have a table PROJECT_BASELINE_ATTR, containing the field
ID
The Hibernate mapping:
<hibernate-mapping package="com.initech.db.model">
<class name="com.initech.db.model.ProjectBaselineAttributes" table="PROJECT_BASELINE_ATTR">
<id name="id" column="id" type="java.lang.Long">
<generator class="sequence">
<param name="sequence">PRO_BASE_ATTR_ID_SEQ</param>
</generator>
</id>
<set name="projects" table="PROJECT" inverse="true" lazy="true" fetch="select">
<key>
<column name="PROJECT_BASELINE_ATTRIBUTES_ID" precision="22" scale="0" not-null="true" />
</key>
<one-to-many class="com.initech.db.model.Project" />
</set>
</class>
</hibernate-mapping>
The respective ProjectBaselineAttributes.java class has the fields
private Long id;
private Set projects = new HashSet();
The current mapping is not ideal, as the relationship between the two tables is actually one-to-one, but in the ProjectBaselineAttributes I have a set of Projects, even though there is always one Projet for one ProjectBaseLineattributes. What should the mapping look like for ProjectBaselineAttributes so that I can get the associated Project "singularly", i.e. so that the class ProjectBaselineAttributes.java would look like this:
private Long id;
private Project project;

Here's the section of the Hibernate documentation which details how to map such a bidirectional one-to-one association using a foreign key.
<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<many-to-one name="address"
column="addressId"
unique="true"
not-null="true"/>
</class>
<class name="Address">
<id name="id" column="addressId">
<generator class="native"/>
</id>
<one-to-one name="person"
property-ref="address"/>
</class>
create table Person ( personId bigint not null primary key, addressId bigint not null unique )
create table Address ( addressId bigint not null primary key )

You can try the below mappings as told in this example.
In the parent bean,
<one-to-one name="one2oneSubA1" class="com.manu.hibernate.mappings.domain.ASub1" cascade="all"
property-ref="parent"/>
In the child bean,
<many-to-one name="parent"
class="com.manu.hibernate.mappings.domain.AMain" column="a_id"
unique="true" cascade="save-update" />