how to delete records from DB with update cascade in hibernate

Question

I want to delete records from DB (MySQL) with update cascade.

There is a day plan and some duration plans associated with this day plan on DB. I want to update the duration list for this day plan.

• When I update the day plan with the duration list that has new or updated duration plans, it works properly and I see these update records on DB.
• However, when I update the day plan with duration list that some duration plans are missing (deleted), nothing happens. I hope that missing duration plans would be deleted.

Example;

• duration plans associated with the day plan on DB; a, b, c.
• I update the day plan with the list that has a(updated), b(no updated).
• I can see on DB that -> 'a' is updated. -> 'b' is no updated. -> * 'c' is NOT DELETED! (How can I delete this 'c' with this update cascade!)

Initializations;

...
    DayPlan dayPlan = new DayPlan();
    Set<DurationPlan> list = new HashSet<DurationPlan>();
...

Preperations to update;

...
    durationPlan = new DurationPlan(dayPlan, x, y, z);
    list.add(durationPlan);
    dayPlan.setDURATION_PLANS(list);
...

Update process with Hibernate-session;

...
session.saveOrUpdate(dayPlan);
...

DurationPlan hibernate-mapping;

<class name="planManagement.DurationPlan" table="DURATIONPLAN">
    <id name="DURATION_PLAN_ID" type="int">
        <column name="DURATION_PLAN_ID" />
        <generator class="native" />
    </id>
    <many-to-one name="DAY_PLAN" class="planManagement.DayPlan" lazy="false" fetch="join">
        <column name="DAY_PLAN_ID" not-null="true"/>
    </many-to-one>
    ...
</class>

DayPlan hibernate-mapping;

<class name="planManagement.DayPlan" table="DAYPLAN">
    <id name="DAY_PLAN_ID" type="int">
        <column name="DAY_PLAN_ID" />
        <generator class="native" />
    </id>
    <set name="DURATION_PLANS" table="DURATIONPLAN" inverse="true" cascade="all" lazy="true" fetch="select">
        <key>
            <column name="DAY_PLAN_ID" not-null="true" />
        </key>
        <one-to-many class="planManagement.DurationPlan" />
    </set>
    ...
</class>

All feedback appreciated!

Answer 1

The problem here is, How hibernate will find which records need to be deleted? As when you call session.saveOrUpdate(dayPlan); where dayPlan will contains list of duration containing only two objects i.e a,b (a(updated), b(no updated).) As per you 'c' need to be deleted but how hibernate will get to know 'c' need to be deleted.