One -to-One & One-to-many & many to one & many to many association in hibernate demonstration

Hibernate - one to one xml declaration:

AbcParentEntity.hbm.xml
====================
<?xml version="1.0"?>
<!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.xyz.entity.AbcParentEntity" table="PARENT_TABLE">
<id name="parentId" type="short">
            <column name="PARENT_COL_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="name" type="string">
            <column name="PARENT_COL_NAME" length="200" />
        </property>

<one-to-one name="childObject" class="com.xyz.entity.AbcChildEntity" cascade="all" />
</class>
</hibernate-mapping>

AbcChildEntity.hbm.xml
===================
<?xml version="1.0"?>
<!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.xyz.entity.AbcChildEntity" table="CHILD_TABLE_1">
        <id name="childId" type="short">
            <column name="CHILD_TAB_COL_ABC_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="childName" type="string">
            <column name="CHILD_TAB_COL_ABC_NAME" length="200" />
        </property>
    </class>

</hibernate-mapping>

One-to-many association in hibernate demonstration

AbcParentEntity.hbm.xml
==========================================
<?xml version="1.0"?>
<!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.xyz.entity.AbcParentEntity" table="PARENT_TABLE">
        <id name="parentId" type="short">
            <column name="PARENT_COL_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="name" type="string">
            <column name="PARENT_COL_NAME" length="200" />
        </property>
        <set name="childObjects1" table="CHILD_TABLE_1" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="CHILD_TAB_COL_ABC_ID" precision="22" scale="0" />
            </key>
            <one-to-many class="com.xyz.entity.AbcChildEntity" />
        </set>
        <set name="childObjects2" table="CHILD_TABLE_2" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="CHILD_TAB_COL_XYZ_ID" precision="4" scale="0" />
            </key>
            <one-to-many class="com.xyz.entity.XyzChildEntity" />
        </set>
    </class>
</hibernate-mapping>

AbcChildEntity.hbm.xml
================================================
<?xml version="1.0"?>
<!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.xyz.entity.AbcChildEntity" table="CHILD_TABLE_1">
        <id name="childId" type="short">
            <column name="CHILD_TAB_COL_ABC_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="childName" type="string">
            <column name="CHILD_TAB_COL_ABC_NAME" length="200" />
        </property>
    </class>
</hibernate-mapping>

XyzChildEntity.hbm.xml
==============================================
<?xml version="1.0"?>
<!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.xyz.entity.XyzChildEntity" table="CHILD_TABLE_2">
        <id name="xyzId" type="big_decimal">
            <column name="CHILD_TAB_COL_XYZ_ID" precision="22" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="xyzName" type="string">
            <column name="CHILD_TAB_COL_XYZ_NAME" length="200" />
        </property>
    </class>
</hibernate-mapping>

AbcParentEntity.java
=================================================
package com.xyz.entity;

import java.util.Set;

import java.io.Serializable;

public class AbcParentEntity implements Serializable {
    private static final long serialVersionUID = 1L;

    private Short parentId;

    private String name;

    private Set<XyzChildEntity> childObjects2;

    private Set<AbcChildEntity> childObjects1;

    public AbcParentEntity() {
    }

    public Short getParentId() {
        return this.parentId;
    }

    public void setParentId(Short parentId) {
        this.parentId = parentId;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }
    public Set<AbcChildEntity> getChildObjects1() {
        return this.childObjects1;
    }

    public void setChildObjects1(Set<AbcChildEntity> childObjects1) {
        this.childObjects1 = childObjects1;
    }

    public Set<XyzChildEntity> getChildObjects2() {
        return this.childObjects2;
    }

    public void setChildObjects2(Set<XyzChildEntity> childObjects2) {
        this.childObjects2 = childObjects2;
    }
}
AbcChildEntity.java
===============================================
package com.xyz.entity;

import java.io.Serializable;

public class AbcChildEntity implements Serializable {
   
    private static final long serialVersionUID = 1L;

    private Short childId;

    private String subVerticalName;


    public AbcChildEntity() {
    }

    public Short getChildId() {
        return this.childId;
    }

    public void setChildId(Short childId) {
        this.childId = childId;
    }

    public String getChildName() {
        return this.childName;
    }

    public void setChildName(String childName) {
        this.childName = childName;
    }


}

XyzChildEntity.java
==============================================
package com.xyz.entity;

import java.math.BigDecimal;
import java.util.Set;
import java.io.Serializable;


public class XyzChildEntity implements Serializable {
    private static final long serialVersionUID = 1L;

    private BigDecimal xyzId;

    private String customerName;

    public XyzChildEntity() {
    }

    public BigDecimal getXyzId() {
        return this.xyzId;
    }

    public void setXyzId(BigDecimal xyzId) {
        this.customerId = xyzId;
    }

    public String getCustomerName() {
        return this.customerName;
    }

    public void setCustomerName(String customerName) {
        this.customerName = customerName;
    }

}


Hibernate - many to one xml declaration:

AbcParentEntity.hbm.xml :
=====================
<?xml version="1.0"?>
<!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.xyz.entity.AbcParentEntity" table="PARENT_TABLE">
<id name="parentId" type="short">
            <column name="PARENT_COL_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>
        <property name="name" type="string">
            <column name="PARENT_COL_NAME" length="200" />
        </property>

</class>
</hibernate-mapping>

AbcChildEntity.hbm.xml :
====================
<?xml version="1.0"?>
<!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.xyz.entity.AbcChildEntity" table="CHILD_TABLE_1">
        <id name="childId" type="short">
            <column name="CHILD_TAB_COL_ABC_ID" precision="4" scale="0" />
            <generator class="assigned" />
        </id>

        <property name="childName" type="string">
            <column name="CHILD_TAB_COL_ABC_NAME" length="200" />
        </property>

<many-to-one name="parentObject" class="com.xyz.entity.AbcParentEntity" cascade="all" />

    </class>
</hibernate-mapping>

Hibernate Many to Many xml declaration:

Tables:

Table_name   Column_Names
 Company company_id, company_name
  Item                   item_id, item_name
Com_Item        company_id, item_id

AbcCompany.hbm.xml :
===================
<?xml version="1.0"?>
<!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.abc.AbcCompany" table="Company">
        <id name="companyId" type="java.lang.Integer">
            <column name="company_id" />
            <generator class="identity" />
        </id>
        <property name="companyName" type="string">
            <column name="company_name" length="10" not-null="true" unique="true" />
        </property>
        <set name="items" table="Com_Item"
        inverse="false" lazy="true" fetch="select" cascade="all" >
            <key>
                <column name="company_id" not-null="true" />
            </key>
            <many-to-many entity-name="com.abc.AbcItem">
                <column name="item_id" not-null="true" />
            </many-to-many>
        </set>
    </class>
</hibernate-mapping>

AbcItem.hbm.xml :
===============
<?xml version="1.0"?>
<!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.abc.AbcItem" table="Item">
        <id name="itemId" type="java.lang.Integer">
            <column name="item_id" />
            <generator class="identity" />
        </id>
        <property name="itemName" type="string">
            <column name="item_name" length="10" not-null="true" unique="true" />
        </property>
        <set name="companies" table="Com_Item"
        inverse="false" lazy="true" fetch="select" cascade="all" >
            <key>
                <column name="item_id" not-null="true" />
            </key>
            <many-to-many entity-name="com.abc.AbcCompany">
                <column name="company_id" not-null="true" />
            </many-to-many>
        </set>
    </class>
</hibernate-mapping>


Table Per Class Hierarchy 

table_name column_names
  Card                   cid, amt,type, ctype, dctype

Card.hbm.xml
==============
<?xml version="1.0"?>
<!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.xyz.Card" table="Card">
<id name="cardId" column="cid" />
<discriminator column="dcolumn" type="string" length="5"/>
<property name="" column="amt" />

<subclass name="com.xyz.CreditCard" discriminator-value="CC">
<property name="creditCardType" column="cctype" length="10" />
</subclass>

<subclass name="com.xyz.DebitCard" discriminator-value="DC">
<property name="debitCardType" column="dctype" length="10" />
</subclass>

</class>

</hibernate-mapping>


Table Per Concrete class

table_name column_names
  Card                   cid, amt
  Credit_Card          cid, amt, ctype
  Debit_Card           cid, amt, dctype

<?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.xyz.Card" table="Card">
<id name="cardId" column="cid" />
<property name="" column="amt" />

<union-subclass name="com.xyz.CreditCard" table="Credit_Card">
<property name="creditCardType" column="cctype" length="10" />
</union-subclass>

<union-subclass name="com.xyz.DebitCard" table="Debit_Card">
<property name="debitCardType" column="dctype" length="10" />
</union-subclass>

</class>
       
</hibernate-mapping>


Table Per Sub class

table_name column_names
  Card                   cid, amt
  Credit_Card          ccid, ctype
  Debit_Card           cdid, dctype


<?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.xyz.Card" table="Card">
<id name="cardId" column="cid" />
<property name="" column="amt" />

<joined-subclass name="com.xyz.CreditCard" table="Credit_Card">
<key column="ccId"></key>  
<property name="creditCardType" column="cctype" length="10" />
</joined-subclass>

<joined-subclass name="com.xyz.DebitCard" table="Debit_Card">
<key column="dcId"></key>  
<property name="debitCardType" column="dctype" length="10" />
</joined-subclass>

</class>
       
</hibernate-mapping>