In this post:
IntroductionBizTalk Mapper 101HistoryBizTalk Mapper in BTS 2004 / 2006 / 2006R2What happens when a map is compiledWhat happens when a map is executedXslTransform vs XslCompiledTransformXSLT 1.0 vs XSLT 2.0Introduction
The BizTalk Mapper is an integral part of the BTS toolkit and, depending on your inclination and experience, you will probably either love, hate it, or not care about it.
At its core, the BizTalk Mapper is simply a visual tool for specifying XSLT
(eXtensible Stylesheet Language Transformations).
This XSLT is used to transform one stream of XML data into another stream of XML data. And since a "stream of XML data" = "message in BizTalk", this means transforming one message into another message.
you might think that the Mapper allows you to specify multiple source or destination messages, but this is actually a trick - BizTalk creates a special schema with one part per input/output message - there's still only one input/output message]
How well the BizTalk Mapper performs its task depends on the complexity of the transformation you're attempting - and the skill/experience of the developer using the BizTalk Mapper!