休眠列表映射约束违反

Question

These are my postresql tables :

CREATE TABLE "user" (
    "id" int4 NOT NULL,
    "activated" bool NOT NULL DEFAULT True,
    CONSTRAINT "user_pkey" PRIMARY KEY("id")
);

CREATE TABLE "user_data" (
    "id" int4 NOT NULL,
    "user_id" int4 NOT NULL,
    "idx" int4 DEFAULT NULL,
    "first_name" text NOT NULL,
    "last_name" text NOT NULL,
    CONSTRAINT "user_data_pkey" PRIMARY KEY("id")
);

My goal is to have in my "User" hibernate bean a direct reference to user's data, like this List<UserData> . Here is my hibernate mapping :

<hibernate-mapping package="mypackage">
    <class name="User" table="user">
        <id name="id" type="long" column="id">
            <generator class="sequence">
                <param name="sequence">user_id_seq</param>
            </generator>
        </id>

        <property name="activated" column="activated" type="boolean" />

        <list name="data" table="user_data" cascade="all">
            <key column="user_id" />
            <list-index column="idx" />
            <one-to-many class="UserData" />
        </list>
    </class>

    <class name="UserData" table="user_data">
        <id 
            name="id" 
            type="long"
            column="id">
            <generator class="sequence">
                <param name="sequence">user_data</param>
            </generator>
        </id> 
        <many-to-one name="user" column="user_id" class="User" />
        <property name="firstName" column="first_name" type="text" />
        <property name="lastName" column="last_name" type="text" />
    </class>    
</hibernate-mapping>

I ran some tests. When I add a new "UserData" to my list and then execute session.saveOrUpdate(myUser) it works, but when I remove an entry from my list and execute the same line, it throws ERROR [JDBCExceptionReporter] ERROR: null value in column "user_id" violates not-null constraint just after telling me that batch update user_data set user_id=null, idx=null where user_id='20' and id='46' was canceled

What is the right usage of this type of mapping? Thank you

EDIT: Adding "inverse=true" isn't adapted to my usage because I need my update on user trigger an update on UserData. Again, maybe I didn't understand the right usage of this type of usage.

Answer 1

It seems like you are trying to update a user_id=null when it has already a not null constraint. Try to remove it or update with a possible user_id.

ERROR: null value in column "user_id" violates not-null constraint just after telling me that batch update user_data set user_id=null, idx=null where user_id='20' and id='46' was canceled

Your mapping syntax is well.

Answer 2

You have to mention the relationship owner in a bi-directional relationship (inverse=true/false).

Default value is false. This means that each time you try to update User object it will also try to update UserData list.

When you set inverse=true then UserData becomes the owner of the bi-directional relationship and hence it will not trigger an update for UserData list when you try update User.

<list name="data" table="user_data" cascade="all" inverse="true">
  <key column="user_id" />
  <list-index column="idx" />
  <one-to-many class="UserData" />
</list>