How to Add unique key in Create Command

abinash84 · **Joined:** Sun Aug 18, 2013 2:39 pm **Posts:** 2

Hi All,

I am new to Hibernate.
My database is SQLLite and it has few constraint like
it does not allow adding constraints using alter table command.

As Hibernate by default creates a table and then alters it i am unable to add unique key constraint to the table
for ref my config files are as below :

Code:

Config File ----
<?xml version='1.0' encoding='utf-8'?>

<!DOCTYPE hibernate-configuration PUBLIC 
"-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

    <!-- hibernate dialect -->
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

    
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost/test</property>
    <property name="hibernate.connection.username">sonu</property>
    <property name="hibernate.connection.password">sonu123</property>
  <!--   <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property> -->
    
    <!-- Automatic schema creation (begin) === -->     
    <property name="hibernate.hbm2ddl.auto">create</property>
 
    <!--hibernate.cfg.xml -->
   <property name="show_sql">true</property>
    
    <!-- Simple memory-only cache -->
   <!--  <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property> -->

     <!-- Enable Hibernate's automatic session context management -->
 <!--     <property name="current_session_context_class">thread</property> -->

    <!-- ############################################ -->
    <!-- # mapping files with external dependencies # -->
    <!-- ############################################ -->


    <mapping resource="com/sample/Person.hbm.xml"/>

</session-factory>
</hibernate-configuration>


hbm file :----
<?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.sample.Person" table="Person">

      <id name="id" column="ID">
         <generator class="native" />
      </id>

        <property name="name">
         <column name="NAME" length="16" not-null="true" unique="true"/>
       </property> 
       
             <property name="surname">
         <column name="SURNAME" length="16" not-null="true" />
      </property>

      <property name="address">
         <column name="ADDRESS" length="16" not-null="true" />
      </property>

   </class>
</hibernate-mapping>

and the generated SQL query is as below :

Hibernate: drop table if exists Person
Hibernate: create table Person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID))
Hibernate: alter table Person add constraint UK_b1dd3vidhowfkune7svm0uh0b unique (NAME)

Please let me know if it is possible to define unique key in the create table query it self ?

Ajit Singh · **Joined:** Wed Feb 06, 2013 2:43 am **Posts:** 46

Hope this helps :

<property name="name" length="16" not-null="true" unique="true">
<column name="NAME"/>
</property>

abinash84 · **Joined:** Sun Aug 18, 2013 2:39 pm **Posts:** 2

Adding like

Code:

 <property name="name" length="16" not-null="true" unique="true">
         <column name="NAME" />
       </property> 

Just runs the create table without alter
Hibernate: create table Person (ID bigint not null auto_increment, NAME varchar(255), SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID))

It does not solve the problem of adding unique key to the table