Hi,

I have a many-to-many relationship between playlist and movie, through a join table playlist_movie. If want to create a new playlist from existing movies, do I need to create a new class PlaylistMovies along with a new hbm table playlistMove.hbm.xml? This class allows me to updated the join table directly without affecting movies.

Is this necessary or is there a better way?

Thanks!

Here's the hbm files of playlist and movies:

<!-- -------------- playlist.hbm.xml -------------- -->
<hibernate-mapping>
<class name="com.magicbillboard.movie.Playlist" table="PLAYLIST">

<id name="id" type="long" column="playlist_id">
<generator class="identity" />
</id>

<!-- 2 association: UserGroup and Movie(s) -->
<many-to-one name="userGroup" outer-join="true" column="usergroup_id" not-null="true"/>

<set name="movies" table="PLAYLIST_MOVIE" lazy="false" cascade="none">
<key column="playlist_id" />
<many-to-many class="com.magicbillboard.movie.Movie" column="movie_id" />
</set>


<!-- properties -->
<property name="name" column="name"/>
<property name="ownershipFlag" column="ownership_flag" type="yes_no"/>
<property name="privateFlag" column="private_flag" type="yes_no"/>
<property name="leafFlag" column="leaf_flag" type="yes_no"/>
<property name="createDate" column="create_dt"/>
<property name="createdBy" column="created_by"/>

</class>
</hibernate-mapping>





<!-- -------------- movie.hbm.xml -------------- -->
<hibernate-mapping>

<class name="com.magicbillboard.movie.Movie" table="MOVIE">

<id name="id" type="long" column="movie_id">
<generator class="identity" />
</id>

<!-- 3 associations: movie metadata, playlists, segments -->
<many-to-one name="movieMetadata" column="movie_metadata_id"/>

<set name="playlists" table="PLAYLIST_MOVIE" lazy="false" inverse="true">
<key column="movie_id" />
<many-to-many class="com.magicbillboard.movie.Playlist" column="playlist_id" />
</set>

<set name="segments" table="SEGMENT" inverse="true" lazy="false" cascade="all">
<key column="movie_id" />
<one-to-many class="com.magicbillboard.movie.Segment" />
</set>

<!-- properties -->
<property name="name" column="name" />
<property name="createDate" column="create_dt" />
<property name="displayTimeSeconds" column="display_time_secs" />
</class>
</hibernate-mapping>

You don't have to have a class modeling the association table if the association table has no other columns. Map the relationship using many-to-many, then

Thanks. After adding movie to playlist, and adding playlist to movie, do I need to do an explicit update on movie before saving playlists? Or would many-to-many mechanism automatically take care of the update on movie?