Specifying One-to-Many Relationship in ATG Repositories
by Frank Kim on Jan.21, 2010, under Repository
(Photo: Monta driving by Yogma)
Specifying one-to-many relationships is ridiculously easy in Ruby on Rails. Unfortunately it’s not so straight-forward in ATG repositories.
First you specify the “belongs to” relationship. In this example the player belongs to a team.
<item-descriptor name="player">
<table name="team_players" type="auxiliary" id-column-names="team_id" shared-table-sequence="1">
<property name="team" column-name="team_id" item-type="team" />
</table>
</item-descriptor>
Then you specify the “has many” relationship. In this example the team has many players.
<item-descriptor name="team">
<table name="team_players" type="multi" id-column-names="player_id" shared-table-sequence="2">
<property name="players" column-name="player_id" data-type="set" component-item-type="player" />
</table>
</item-descriptor>
Note the trick is specifying the “shared-table-sequence.”
Here is the SQL for the table that specifies this relationship in our example.
CREATE TABLE team_players ( team_id VARCHAR2(40) NOT NULL, player_id VARCHAR2(40) NOT NULL, CONSTRAINT team_players_pk PRIMARY KEY (team_id, player_id), CONSTRAINT team_players_players_fk foreign key (player_id) references players (id), CONSTRAINT team_players_team_fk foreign key (team_id) references teams (id) );
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February 16th, 2010 on 7:01 PM
column-name and id-column-names should interchange ?
February 16th, 2010 on 8:35 PM
hi pavithra,
thanks for your comment.
i’m not sure what you mean though. are you saying that the column-name and id-column-names should be switched in my code example? i believe it’s correct.
thanks,
frank