org.hrorm

Interface AssociationDao<LEFT,RIGHT>

Type Parameters:

LEFT - One of the associated entities

RIGHT - The other of the associated entities

All Known Implementing Classes:

AssociationDaoImpl

public interface AssociationDao<LEFT,RIGHT>

A DAO that can find and persist associations between entities. An AssociationDao is used for managing many-to-many relations that are stored in a third table, not by directly joining the entity tables themselves.

The entity table must have exactly three columns, all integers:

1. A primary key
2. A foreign key to the left entity
3. A foreign key to the right entity

Note that the names LEFT and RIGHT are simply tuple names, and have nothing to do with left joins or right joins.

Method Summary

Modifier and Type	Method and Description
void	deleteAssociation(LEFT left, RIGHT right) Remove an association from the underlying store
Long	insertAssociation(LEFT left, RIGHT right) Persist a new association between two entities.
List<LEFT>	selectLeftAssociates(RIGHT right) Finds all the instances of LEFT entities associated with the RIGHT instance passed.
List<RIGHT>	selectRightAssociates(LEFT left) Finds all the instances of RIGHT entities associated with the LEFT instance passed.

Method Detail

selectLeftAssociates

List<LEFT> selectLeftAssociates(RIGHT right)

Finds all the instances of LEFT entities associated with the RIGHT instance passed.

Parameters:

right - The entity instance whose associates are to be selected

Returns:

All the instances found

selectRightAssociates

List<RIGHT> selectRightAssociates(LEFT left)

Finds all the instances of RIGHT entities associated with the LEFT instance passed.

Parameters:

left - The entity instance whose associates are to be selected

Returns:

All the instances found

insertAssociation

Long insertAssociation(LEFT left,
                       RIGHT right)

Persist a new association between two entities.

Parameters:

left - an instance of the LEFT entity to be associated

right - and instance of the RIGHT entity to be associated

Returns:

the primary key of the association record

deleteAssociation

void deleteAssociation(LEFT left,
                       RIGHT right)

Remove an association from the underlying store

Parameters:

left - an instance of the LEFT entity whose association is to be broken

right - and instance of the RIGHT entity whose association is to be broken