PATH WebObjects 4.0 Documentation > EOAccess Reference

EOJoin

Inherits From:
NSObject

Conforms To: NSObject (NSObject)

Declared in: EOAccess/EOJoin.h

Class Description

An EOJoin describes one source-destination attribute pair for an EORelationship. See the EORelationship class specification for more information and for examples.

Method Types

Initializing new instances - initWithSourceAttribute:destinationAttribute:
Querying the join - destinationAttribute - isReciprocalToJoin: - sourceAttribute

Instance Methods

destinationAttribute

- (EOAttribute *)destinationAttribute

Returns the destination ("right") attribute used by the join.

See also: - destinationAttributes (EORelationship)

initWithSourceAttribute:destinationAttribute:

- initWithSourceAttribute:(EOAttribute *)source destinationAttribute:(EOAttribute *)destination

Initializes a newly allocated EOJoin with the given source and destination attributes. This is the designated initializer for the EOJoin class. Returns self.

See the EORelationship class specification for an example of creating a relationship using EOJoins.

See also: - addJoin: (EORelationship)

isReciprocalToJoin:

- (BOOL)isReciprocalToJoin:(EOJoin *)otherJoin

Returns YES if this join's source attribute is equal to otherJoin's destination attribute and otherJoin's source attribute is equal to this join's destination attribute. This is known as a back-referencing join.

See also: - inverseRelationship (EORelationship)

sourceAttribute

- (EOAttribute *)sourceAttribute

Returns the source ("left") attribute used by the join.

See also: - sourceAttributes (EORelationship)