Java – using PostgreSQL, why doesn’t hibernate / JPA create cascading constraints?

I have an entity:

@OneToMany(cascade = CascadeType.ALL,mappedBy = "bar")
private Set<Foo> fooSet;

An entity foo:

@ManyToOne(optional = false)
@JoinColumn(name = "bar_id")
private Bar bar;

Hibernate in foo Create foreign key constraint on bar – > bar ID, but it does not specify on delete cascade Why not? Is there any way to achieve it?

Or I can manually add on delete cascade in the DB (and disable DDL generation). Is this a good habit? Also, do I have to modify my code in some way to let hibernate know that the database will automatically delete relevant records?

thank you.

Update – this is my JPA / Hibernate / PostgreSQL configuration:

<bean id="dataSource" class="org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy">
    <constructor-arg>
        <bean class="org.springframework.jdbc.datasource.DriverManagerDataSource">
            <property name="driverClassName" value="org.postgresql.Driver" />
            <property name="url" value="jdbc:postgresql://localhost:5432/my_db" />
            <property name="username" value="my_username" />
            <property name="password" value="my_password" />
        </bean>
    </constructor-arg>
</bean>
<bean id="jpaAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
    <property name="databasePlatform" value="org.hibernate.dialect.PostgresqlDialect" />
    <property name="showsql" value="true" />
    <property name="generateDdl" value="true" />
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerfactorybean">
    <property name="jpaVendorAdapter" ref="jpaAdapter" />
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.format_sql">true</prop>
            <prop key="hibernate.hbm2ddl.auto">update</prop>
        </props>
    </property>
    <property name="dataSource" ref="dataSource" />
</bean>

Update 2 – clarified what I meant: a foreign key constraint was created, but I wondered why it did not specify on delete cascade (the original problem was changed accordingly)

Solution

Hibernate manages cascading operations manually More importantly, if you want to cascade on the database instead of declaring them in Hibernate (due to performance problems), you may encounter errors in some cases This is because hibernate stores entities in its session cache, so it does not know whether the database will be cascaded deleted

When you use L2 cache, your situation is worse because this cache has a longer lifetime than the session, and such changes on DB side will not be visible to other sessions because the old values are stored in this cache

I have read some hibernate sources (very unpleasant experience). I doubt that cascading can be managed on the database side under any circumstances - hibernate design has too many assumptions that are incompatible with the reality of DB