remove duplicate rows from database with hibernate

Question

I have an hbm file which is as below:

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping auto-import="true" default-lazy="false">
    <class name="com.saman.entity.hibernate.EmployeeEntity"
           table="Employee" optimistic-lock="version">
        <id name="id">
            <column name="Id" sql-type="bigint"/>
            <generator class="native"/>
        </id>
        <timestamp name="version" source="db"/>
        <property  name="firstName">
            <column name="FirstName" sql-type="nvarchar(300)"/>
        </property>
        <property name="lastName">
            <column name="LastName" sql-type="nvarchar(300)"/>
        </property>
        <property name="employeeType">
            <column name="EmployeeType" sql-type="nvarchar(300)"/>
        </property>
        <set name="shifts" table="Shifts" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="Id" not-null="true"/>
            </key>
            <one-to-many class="com.saman.entity.hibernate.ShiftEntity"/>
        </set>
    </class>
</hibernate-mapping>

now I wanted if I add an employee and persist it, if then I add another employee with the previous information, my system raises an exception and tell me that I have another employee in the database with that informations.

does hibernate give me this option?

Do you want to find if all informations are same or part of it is enough. I mean you have an id column and it must be unique. If you try to add another person with same id hibernate should throw and exception. — mbaydar
– mbaydar, Commented May 10, 2012 at 12:05
i know we have id, but consider there is a person with name "alex" and family "peterson". i wanted to tell my system that prevents adding another body with these informations. — saman
– saman, Commented May 10, 2012 at 12:10

Sudhakar · Accepted Answer · 2012-05-10 14:58:24Z

1

Well just add this to your mapping

<properties name="firstName_lastName_unique" unique="true">
        <property name="firstName"/>
        <property name="lastName"/>
</properties>

answered May 10, 2012 at 14:58

Sudhakar

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Community · Accepted Answer · 2017-05-23 10:34:43Z

0

I think I understand what you want to achieve. But I don't know if you search your problem in stackoverflow first. This might be your answer How to do multiple column UniqueConstraint in hbm?

edited May 23, 2017 at 10:34

CommunityBot

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answered May 10, 2012 at 12:25

mbaydar

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shawsy · Accepted Answer · 2012-05-10 12:26:07Z

0

Have you set an auto increment on the ID column in your database?

answered May 10, 2012 at 12:26

shawsy

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Johanna · Accepted Answer · 2012-05-10 12:51:02Z

0

You already have a generator for the id value. This should generate a unique id, but it only does so if these two conditions are true:

The column either is defined as autoincrement (p. ex. MySQL) or has a sequence (p. ex. Oracle)
When saving a new row, the member variable id is set to 0.

I can imagine, when you save a new value with previous information, the variable id still has a value != 0, and in this case the database uses the given value instead of generating a new unique one, which will fail due to the unique constraint.

This error also can appear if there is a second unique index on the table.

answered May 10, 2012 at 12:51

Johanna

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