= Term: EntityType =

[wiki:EntityType EntityTypes] are those concepts defined in an !InfoGrid [wiki:Model] whose instances can stand by themselves and do not depend on other instances. Contrast with [wiki:RelationshipType RelationshipTypes], which are those concepts defined in an !InfoGrid [wiki:Model] whose instances depend on other instances (the source and destination MeshObject).

Any MeshObject may be blessed with one or more [wiki:EntityType EntityTypes].

EntityType is similar to the concept of a class in UML, or the notion of an entity in entity-relationship or information modeling. However, as all concepts in an InfoGrid [wiki:Model], [wiki:EntityType EntityTypes] are a conceptual-level concept and do not reflect their implementation in a particular programming language or storage technology. For example, instances of [wiki:EntityType EntityTypes] may be stored in relational databases, in XML files, in object databases, encrypted or in memory without any impact on the definition of the EntityType.

[wiki:EntityType EntityTypes] support single and multiple inheritance. They may define one or more [wiki:PropertyType PropertyTypes].

For example, in an ordering system, `Customer`, `Order`, and `LineItem` each are an EntityType. `Customer_Places_Order`, and `Order_Contains_LineItem` each are a RelationshipType. `Customer_FirstName`, `Order_PlacedOn` etc. each is a PropertyType.

See also:
 * MeshObject
 * PropertyType
 * [wiki:Relationship] and RelationshipType.