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Hydro Features
Source Features
Channel System
How to read
this diagram
Copyright ESRI 2001. All Rights R eserved.
Types of Classes
An ESRI Object class cannot be used tocreate new objects but is a specificationfor instances of subclasses (through typeinheritance).
An Abstract class is a class for which noinstances may be created. In a classdiagram you indicate that a class isabstract by showing its title in italics.
A Feature class is a class for objects thatinherit from the feature class. Featureclasses can also be associated withCoded Value Domains and Subtypes.
A Multiplicity is a constraint on the number ofobjects that can be associated with another object.Association, aggregration and compositionrelationships have multiplicities on both sides. Thisis the notation for multiplicities: 1 One and only one (if none shown, ’1’ is implied) 0..1 Zer o or one M..N From M to N (positive integers) * or 0..* From zero to any positive integer 1..* From one to any positive integer
Aggregation is an asymmetricassociation in which an object fromone class is considered to be a"whole" and objects from the otherclass are considered "parts".
Composition is a stronger form ofaggregation in which objects from the"whole" class control the lifetime ofobjects from the "part" class.
Type Inheritance
Association 1..*Multiplicity
DomainDomain
Composition
ESRI Class
*
Abstract Class
Subtype
Attributes
FeatureClass
FeatureClass
Attributes Attributes
Types of RelationshipsAssociations represent relationshipsbetween classes. They have definedmultiplicities at both ends.Type inheritance defines specializedclasses of objects which share propertiesand methods with the superclass and haveadditional properties and methods.Instantiation specifies that one object fromone class has a method with which itcreates an object from another class.
An N-ary association specifies thatmore than two classes are associated.A diamond is placed at the intersectionof the association branches. Thisdiagram has several examples of aninstantiation of an object from twoother objects.
Subtype
Subtype
1
Feature MetaData
Time Series
Flow
Tim
e
Flow
Ti
m
e
CRWR
CRWRCRWR
1
Hydro Network
1Drainage System
1..*
Subtype
1
1