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When describing Ecore's modelling constructs below, we will take the latter of these perspectives. For the code perspective, see Genmodel.

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Main modelling

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elements

Ecore supports classes with attributes (properties of simple types), associations (references to other modelled classes) and operations, and multiple inheritance. The main construct is the class, which is called EClass in Ecore terminology. An EClass contains (structural) features, which are either attributes or references (one-way associations) and operations, and can be related to other classes through inheritance.

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class OrgUnit
class Person

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

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

class Named {
	String name
}

class OrgUnit extends Named
class Person extends Named

object "~#o1: OrgUnit" as o1 {
	name = "IDI"
}
object "~#p1: Person" as p1 {
	name = "Hallvard"
}

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

object "~#o1: OrgUnit" as o1 {
	name = "IDI"
}
object "~#p1: Person" as p1 {
	name = "Hallvard"
}
o1 <- p1: works-in

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

object "~#o1: OrgUnit" as o1 {
	name = "IDI"
}
object "~#p1: Person" as p1 {
	name = "Hallvard"
}
object "~#p2: Person" as p2 {
	name = "Letizia"
}
o1 <-- p1: works-in
o1 --> p1: workers
o1 <-- p2: works-in
o1 --> p2: workers

class OrgUnit {
   void fire(Person)
}
class Person {
}

Packages

The classes and data types (EClassifiers) in an Ecore model must be inserted into an EPackage as its classifiers. Hence, an Ecore model will consist of one or more EPackages containing EClasses and EDataTypes. The EPackage has a name and an identifier (nsUri), the latter must be globally unique, and typically is or includes the identifier of the software module (e.g. Eclipse plugin, OSGi bundle or maven module) containing the model. Take care when deciding on the name and nsUri as these will be used by tools. E.g. the name is used by the code generator as the last element of the Java package for the generated classes, and the nsUri is used for looking up the package in a global registry.

Annotations

Ecore includes a mechanism for attaching extra data to all the above modelling elements, in the form of key-value pairs. The extra data is typically used by tools, e.g. it is used for naming constraints (that will need to be implemented by hand in the generated code, see Validation) and providing method bodies for the code generator. You may also add your own custom annotations that are utilised by your own tools.

An annotation is added as an EAnnotation object to a model element, and its source attribute is used as a qualifier to identify its meaning/purpose. This qualifier is typically an URI or qualified name that identifies the tool that uses it. E.g. to use Ecore-specific annotation you use http://www.eclipse.org/emf/2002/Ecore as the source attribute value. The annotation data are added as key-value pairs and value in the annotation's details map.