Unique constraint error on inserting data

Question

I am getting strange error Caused by:

java.sql.SQLIntegrityConstraintViolationException: ORA-00001: unique constraint

While executing my below code:

Product DAO.java

@Id
@Column(name = "no", columnDefinition = "NUMBER")
private int serial_number;
//No getter and setter for this field

@Column(name = "fname", columnDefinition = "VARCHAR2(50)")
private int fname;

@Column(name = "lname", columnDefinition = "VARCHAR2(50)")
private int lname;
// Getter and setter for fname and lname


ProductService.java

Product po = new Product();
po.setfname = "Tom";
po.setlname = "John";
//I am not setting 'no' field value since I have created sequence in my oracle table to auto increment the value.

When I am running this code, I am getting unique constraint error on field 'no'. Can anyone help me in identifying what I am doing wrong in my code. When I have already created sequence for 'no' field in my table, do I need to make any change in config file or code? Since its the production database, I do not know the sequence name also.

hibernate-cgf.xml
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>
        <property name="hibernate.connection.password">pass</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">update</property>
        <mapping class="dao.Product"></mapping>
    </session-factory>
</hibernate-configuration>

Just creating a sequence doesn't do anything. How have you associated it with the table, if you have - via a trigger, or as the default value for the column? — Alex Poole
– Alex Poole, Commented Feb 20, 2017 at 16:03

Bulat · Accepted Answer · 2019-07-02 13:11:10Z

2

Your id field serial_number is an int which is initialized to zero, and your mapping for @Id does not include a @GeneratedValue annotation, so hibernate will assume you are assigning the id manually and save it as zero every time you persist an object, causing the SQLIntegrityConstraintViolationException. You need to add a @GeneratedValue annotation and you can also choose a strategy, like this:

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "no", columnDefinition = "NUMBER")
private int serial_number;

edited Jul 2, 2019 at 13:11

Bulat

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answered Feb 20, 2017 at 16:29

Benjamin Baron Rodriguez

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2 Comments

user4324324 Over a year ago

Thanks. It works! I have used @GeneratedValue(strategy = GenerationType.SEQUENCE)

user4324324 Over a year ago

Will @GeneratedValue(strategy = GenerationType.AUTO) use the sequence created in my table ? Beacuse I am always seeing this line Hibernate: select hibernate_sequence.nextval from dual

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