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EClass

Has a name and can be abstract (cannot be instantiated) and interface (purely API). A container of so-called structural features (attributes and associations).

Example:

class OrgUnit
class Person

Non-abstract classes can be instantiated. Instances will have attributes values and links to other objects corresponding to contained and inherited features.

object "~#o1 : OrgUnit" as o1
object "~#p1 : Person" as p1

EDataType

A non-modelled or "foreign" type, provided by the host language and runtime environment, like int, double, String, Date etc. Many such types are pre-defined by Ecore, e.g. EInt, EIntegerObject, EDouble, EDoubleObject, EBoolean, EBooleanObject, EString, EDate corresponding to Java's int, Integer, double, Double, boolean, Boolean, String and Date types. You can define your own, to be able to use other Java types in your model.

EClassifier

Abstract superclass of EClass and EDataType

EAttribute

Has a name, type (an EDataType) and multiplicity (lower and upper bounds).

class OrgUnit {
	String name
}
class Person {
	String name
}

EReference

Has a name, type (an EClass) and multiplicity. Corresponds to a one-way/directed association from the owning EClass to another EClass.

class OrgUnit {
}
class Person {
}
OrgUnit <- Person: works-in

Two EReferences may be each other's opposite, meaning that of one instance refers to the other, the other must refer back.

class OrgUnit {
}
class Person {
}
OrgUnit -> "*" Person: workers
OrgUnit <- Person: works-in

class OrgUnit {
}
class Person {
}
OrgUnit "works-in" <--> "workers *" Person

EStructualFeature

Abstract superclass of EAttribute and EReference. The distinction between these two is the kind of type they have, EDataType and EClassifier, respectively.