Hibernate Cascade

Transitive Persistence

Normally used to <one-to-many> and <one-to-one>: "one" side
Not suggest for <many-to-one> and <many-to-many>: "many" side

1. Can used in <Set> and also <Property>
2. Used in <one-to-many>, "one" side
3. Used in <one-to-one>, primary object side

Cascade options:

none

all

save-update: 

delete

lock

refresh

evict

replicate

persist

merge

delete-orphan(one-to-many)

Examples: 

cascade="all"

cascade="persist,merge,save-update"

cascade="delete"

Example:(one-to-many)

Auto delete students when delete a department.

in Department.hbm.xml

<set name="students" cascade="delete">

<key column="dept_id"/>

<one-to-many class="student" />

</set>

when doing delete a department, all students in its <set> will be deleted

Example:(one-to-many)

Auto add/update students when save a department.

in Department.hbm.xml

<set name="students" cascade="save-update">

<key column="dept_id"/>

<one-to-many class="student" />

</set>

When save a department, all students in its <set> will be saved/updated

Example:(many-to-one)

Auto add/update department when save a student

in Student.hbm.xml

<many-to-one name="department" column="dept_id" cascade="save-update">

<key column="dept_id"/>

<one-to-many class="student" />

</set>

When saving/updating a student, its department will also be saved/updated