Entity Namespace Concept
Published: May 2010
Entities in Office SharePoint Server 2007 were named and scoped to the LobSystem object. In Microsoft SharePoint Server 2010, entities (external content types) are a core concept and are globally available. The concept of an LobSystem object is still useful as a placeholder for connection, authentication, and proxy information, but its prominence in the object model is reduced.
Because an instance of a Microsoft Business Connectivity Services (BCS) service application can have many entities, Business Connectivity Services introduces the concept of an Entity Namespace, which is a Unicode string with a maximum length of 255 characters. The Entity Name, when concatenated with the Namespace and the Entity Version, forms a GUID for an Entity object. The namespace is an opaque token to the BDC and can be used in the same manner as an XML namespace (or a .NET Framework class namespace). If you are adopting namespace conventions such as those for the .NET Framework (which are hierarchical), be aware that there is no support for the hierarchical enumeration of elements in the perceived sub-namespaces of the string.