Facts are discrete pieces of information about the world. Facts can originate from many sources (event systems, objects in business applications, database tables, and so on), and must be fed into the Business Rule engine in BizTalk Server by using one of the following elements:
.NET objects (methods, properties, and fields)
XML documents (elements, attributes, and document subsections)
Database rowsets (values from table column)
In the Business Rule Composer, you can use the Facts Explorer to browse and bring data into your rules from various sources.