StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POSelf referencing symmetrical Hibernate Map Table using @ManyToMany
primarykey
Id
2501306
data
AcceptedAnswerId
2503828
AnswerCount
3
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2010-03-23T15:44:19.727
FavoriteCount
4
LastActivityDate
2010-05-09T13:17:23.030
LastEditDate
2010-05-09T13:17:23.030
LastEditorUserId
70604
OwnerUserId
169889
ParentId
0
PostTypeId
1
Score
1
ViewCount
1707
LastEditorDisplayName
text
Body
I have the following class <pre><code>public class ElementBean { private String link; private Set<ElementBean> connections; } </code></pre> I need to create a map table where elements are mapped to each other in a many-to-many symmetrical relationship. <pre><code>@ManyToMany(targetEntity=ElementBean.class) @JoinTable( name="element_elements", joinColumns=@JoinColumn(name="FROM_ELEMENT_ID", nullable=false), inverseJoinColumns=@JoinColumn(name="TO_ELEMENT_ID", nullable=false) ) public Set<ElementBean> getConnections() { return connections; } </code></pre> I have the following requirements When element A is added as a connection to Element B, then element B should become a connection of Element A. So A.getConnections() should return B and B.getConnections() should return A. I do not want to explicitly create 2 records one for mapping A to B and another for B to A. Is this possible? UPDATE : Thank you for all the suggestions. When I try @Pascal's suggestion two records are created as follows when I try to connect element 1 with element 2. FROM_ELEMENT_ID, TO_ELEMENT_ID 1, 2 2, 1 I want the records to be symmetrical where 1,2 is the same as 2,1 How is this issue dealt with? Update I explicitly created a map bean <pre><code>class ConnectionBean { ElementBean from; ElementBean to; } @NotNull @ManyToOne @JoinColumn(name="FROM_ELEMENT_ID", nullable=false) public ElementBean getFrom() { return from; } @NotNull @ManyToOne @JoinColumn(name="TO_ELEMENT_ID", nullable=false) public ElementBean getTo() { return to; } </code></pre> I updated the ElementBean to <pre><code>public class ElementBean { private String link; private Set<ConnectionBean> from; private Set<ConnectionBean> to; } @OneToMany(mappedBy="from", fetch=FetchType.LAZY) public Set<ConnectionBean> getFrom() { return from; } @OneToMany(mappedBy="to", fetch=FetchType.LAZY) public Set<ConnectionBean> getTo() { return to; } </code></pre> Here I can control the insertion and deletion. For example before inserting a new ConnectionBean, I check to see if a connection exists between elements A & B by checking the Connection table for records where ((from == A && to == B) || (from == B && to == A)) before insertion.
Tags
<java><hibernate><orm><many-to-many><jointable>
Title
Self referencing symmetrical Hibernate Map Table using @ManyToMany
singulars
PostAcceptedAnswerId
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USPascal Thivent
UserOwnerUserId
1. USsmahesh
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
2. PO
 singulars
 PostTypePostTypeId
 PTAnswer
3. PO
 singulars
 PostTypePostTypeId
 PTAnswer
VotesPostIdCreationDate
CommentsPostId
1. This table or related slice is empty.

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.