Survey of Schema Languages: On a Software Complexity Metric

Length in Schema (LIS) is a numerical measurement of the schema documents (DS) of extensiblemarkup language (XML) that contain schemas from xml schema language in a manuscript form. LIS likened to source line of codes (SLOC) in software complexity which is used to calculate the amount of effort that will be required to develop a schema document. Different LIS were considered such as Blank Length in Schema (BLIS), Total Length in Schema (TLIS), Commented Length in Schema (CLIS) and Effective Length in Schema (ELIS) for sixty (60) different schema documents acquired online through Web Services Description Language (WSDL) and implemented in two schema languages: Relax-NG (rng) and W3C XMLschema (wxs) to estimate schema productivity and maintainability. It was discovered that overall understandability and flexibility of schemas become much easier with less maintenance efforts in rng than wxs.