Biztalk Visual Studio

BizTalk uses a combination of namespace#rootnode to define the schema type of a message, thereby making a MessageType unique (for example: http://mynamespace.com#MyRootNode). In other words, BizTalk uses this combination to identify and resolve schemas references.

Yes, we can have a schema without target namespace and its message type will be the Root node.

Clean Solution is used to delete any intermediate and output files (mostly assemblies). With only the project and component files left, new instances of the intermediate and output files (mostly assemblies) can then be built.

Build means compile and link only the source files that have changed since the last build, while Rebuild means compile and link all source files regardless of whether they changed or not.

Yes. Technically it is possible.

An <Any> element in a schema designates a specific location in the schema where new elements or attributes can be added. When BizTalk uses the schema to process a message containing unknown elements or attributes in the designated location, the schema will still consider the message valid.