save-update with Cascade

Let’s perform Save-Update operations with and without cascade to understand it better

save-update with Cascade

Annotation configuration

Applicant.java

@OneToMany(mappedBy="applicant")

@Cascade(CascadeType.SAVE_UPDATE)

    private Set<Address> addresses;

XML configuration

applicant.hbm.xml

<set name="addresses" table="Address" 
                inverse="true" lazy="true" fetch="select" cascade="save-update">
            <key>
                <column name="Applicant_Id" not-null="true" />
            </key>
            <one-to-many class="Address" />
        </set>

Example to persist Applicant and Address objects

Applicant applicant = new Applicant();
		applicant.setFirstName("John");
		applicant.setLastName("KC");
		applicant.setAge(28);
		applicant.setEducation("Graduation");

		Address currentAdd = new Address();
		currentAdd.setStreet("Royal road");
		currentAdd.setCity("Newyork");
		currentAdd.setZipcode("10001");
		
		
		Address permanentAdd = new Address();
		permanentAdd.setStreet("Manyar Road");
		permanentAdd.setCity("Sydney");
		permanentAdd.setZipcode("2060");
		
		Set<Address> addresses = new HashSet<Address>();
		addresses.add(currentAdd);
		addresses.add(permanentAdd);
		applicant.setAddresses(addresses);
		session.save(applicant);

We can observe that, we are saving only Applicant object in the above code but Address objects will also be saved automatically due to Cascade.

Output Queries generated

insert 

    into

        Applicant

        (Age, Education, FirstName, LastName, Applicant_Id) 
    values
        (?, ?, ?, ?, ?)


    insert 

    into

        Address
        (Applicant_Id, City, Street, Zipcode, Address_Id) 
    values
        (?, ?, ?, ?, ?)


    insert 

    into

        Address
        (Applicant_Id, City, Street, Zipcode, Address_Id) 
      values
        (?, ?, ?, ?, ?)

We can see that insert queries for Address are also executed even though we saved only Applicant which means Cascade has happened from Applicant to Address.

Output in DB

save-update without Cascade

If we want to save both Applicant and its reference Address without using Cascade , we need to save them individually

Annotation configuration

Applicant.java

@OneToMany(mappedBy="applicant")

    private Set<Address> addresses;

XML configuration

applicant.hbm.xml

<set name="addresses" table="Address" 
                inverse="true" lazy="true" fetch="select">
            <key>
                <column name="Applicant_Id" not-null="true" />
            </key>
            <one-to-many class="Address" />
        </set>

Example to persist Applicant and Address objects

        Applicant applicant = new Applicant();
		applicant.setFirstName("John");
		applicant.setLastName("KC");
		applicant.setAge(28);
		applicant.setEducation("Graduation");

		Address currentAdd = new Address();
		currentAdd.setStreet("Royal road");
		currentAdd.setCity("Newyork");
		currentAdd.setZipcode("10001");
		
		
		Address permanentAdd = new Address();
		permanentAdd.setStreet("Manyar Road");
		permanentAdd.setCity("Sydney");
		permanentAdd.setZipcode("2060");
		
		Set<Address> addresses = new HashSet<Address>();
		addresses.add(currentAdd);
		addresses.add(permanentAdd);
		applicant.setAddresses(addresses);
		session.save(applicant);
                session.save(currentAdd);
		session.save(permanentAdd);

In the above code, we are using session.save(currentAdd) and session.save(permanentAdd) to save the address objects.
and we are using session.save(applicant) to save the Applicant object.

Output Queries generated

insert 

    into

        Applicant
        (Age, Education, FirstName, LastName, Applicant_Id) 
    values
        (?, ?, ?, ?, ?)


    insert 

    into

        Address
        (Applicant_Id, City, Street, Zipcode, Address_Id) 
    values
        (?, ?, ?, ?, ?)


    insert 

    into

        Address
        (Applicant_Id, City, Street, Zipcode, Address_Id) 
    values
        (?, ?, ?, ?, ?)

We can see that insert queries for Address are also executed as we saved them explicitly in the above code using session.save(currentAdd) and session.save(permanentAdd)

” If we use Cascade then no need to write this additional code to save the references. “

Output in DB

Raj

Founder of javainsimpleway.com
I love Java and open source technologies and very much passionate about software development.
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