Use of XML

Most enterprise reporting solutions use proprietary binary formats. This locks developers into using that vendor's tools to generate and deploy reports . Obviously, this runs counter to SSRS's design goal of generating open standards. The other thing to note about SSRS is the idea to keep report designers and generators separate. This poses the fundamental challenge of what open format allows such disparate things to communicate. Thankfully, the answer already existedXML.

XML is already in use throughout the Web and even in many non-Web systems as a communication mechanism. It easily allows anyone with a text editor to create an XML file. XML is similar to HTML in that it is a form of markup language. There are a few major differences.

With XML, a document has to be well formed , meaning every beginning markup tag (called a node) has to have a corresponding ending tag. Second, HTML only has a few keywords that can be used to mark up text. XML doesn't have any such limitation because the end user is the one responsible for the creation of tags. The tags are used to describe the data encompassed by them. This is in stark contrast to HTML, which describes how to handle presentation of data. This makes XML an ideal communication medium or language.

The one drawback about such a flexible medium is, ironically enough, its flexibility. Immediately, you might wonder the following: If any node can be in any place, and any node can have any attribute, how can this be effective? There have to be some rules. To solve this problem, you need to create an XML schema. An XML schema allows the creation of a contract to adhere to between different systems by defining when and where in the document a set of XML nodes should appear, and which nodes should have attributes describing them.

The RDL specification is the XML schema that describes the layout of the XML used to create reports. The XML itself basically becomes the programming language of the report.