<?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="test.Quotation" table="QUOTATION">
        <id name="id" column="QUOTATION_ID">
            <generator class="native"/>
        </id>
        <property name="name"/>
        <property name="price"/>
    </class>
</hibernate-mapping>


public class Quotation {
   
    /** Creates a new instance of Quotation */
    public Quotation() {
        setName("noname");       
        setPrice(0.0);       
    }

    public Quotation(String name, double price) {
        setName(name);       
        setPrice(price);               
    }
   
    private Long id;
    private double price;
    private String name;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

        Quotation q1 = new Quotation("sugar", 100);
        Quotation q2 = new Quotation("sugar", 200);
        Quotation q3 = new Quotation("sugar", 100);
       
        session.save(q1);
        session.save(q2);
        session.save(q3);

         | ID | NAME | PRICE
------------------------------------------
         | 1  | sugar  | 100
         | 2  | sugar  | 200
         | 3  | sugar  | 100  <-- I wish this col will not be saved, since it is having same name and price as the first col.

<?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="test.Quotation" table="QUOTATION">
        <id name="id" column="QUOTATION_ID">
            <generator class="native"/>
        </id>
        <composite-id>
            <key-property name="name" column="NAME"/>
            <key-property name="price" column="PRICE"/>           
        </composite-id>
    </class>
</hibernate-mapping>

package test;

/**
*
* @author YC Cheok
*/
public class Quotation implements java.io.Serializable {
   
    /** Creates a new instance of Quotation */
    public Quotation() {
        setName("noname");       
        setPrice(0.0);       
    }

    public Quotation(String name, double price) {
        setName(name);       
        setPrice(price);               
    }
   
    public boolean equals(Object o) {
        if(!(o instanceof Quotation))
            return false;
       
        Quotation quotation = (Quotation)o;
       
        return this.price == quotation.price && this.name.equals(quotation.name);
    }
   
    public int hashCode() {
        int result = 37;

        final long tmp = Double.doubleToLongBits(price);
        result = 37 * (int)(tmp ^ (tmp >>> 32));

        result = 37 * result + name.hashCode();
       
        return result;
    }
   
    private Long id;
    private double price;
    private String name;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

...
Caused by: org.xml.sax.SAXParseException: The content of element type "class" must match "(meta*,subselect?,cache?,synchronize*,comment?,tuplizer*,(id|composite-id),discriminator?,natural-id?,(version|timestamp)?,(property|many-to-one|one-to-one|component|dynamic-component|properties|any|map|set|list|bag|idbag|array|primitive-array)*,((join*,subclass*)|joined-subclass*|union-subclass*),loader?,sql-insert?,sql-update?,sql-delete?,filter*,resultset*,(query|sql-query)*)".