Differentiate between validating and non validating xml parser
One of the key strengths of XML, sometimes called "late binding," is the decoupling of the writer and the reader of an XML document: this gives the reader the ability to have its own interpretation and understanding of the document.By being more prescriptive about the way to interpret a document, XML schema languages reduce the possibility of erroneous interpretation but also create the possibility of unexpectedly adding "value" to the document by creating interpretations not apparent from an examination of the document itself.What is the difference between validation and parsing?I know parsing check file structure (grammar), so may be checked as OK in parsing function, but may be WRONG in validation process because there is no attr value like "pink"? Parsing checks that the input conforms to the rules in the XML specification, for example that every start tag has a matching end tag.
In the remainder of this article, I will be using the following simple library application to illustrate the use of the various schema languages.
These transformations take instance documents as input and produce a validation report, which includes at least a return code reporting whether hhe document is valid and an optional Post Schema Validation Infoset (PSVI), updating the original document's infoset (the information obtained from the XML document by the parser) with additional information (default values, datatypes, etc.) One important consequence of realizing that XML schemas define transformations is that one should consider general purpose transformation languages and APIs as alternatives when choosing a schema language.
Before we dive into the features of XML schema languages, I'd like to step back and look at the downsides of the use of any schema language.
Validation checks that the input conforms to the rules of a specific XML vocabulary, for example that a table contains exactly one thead and one tbody.
In ordinary English, a schema is defined as "an outline or image universally applicable to a general conception, under which it is likely to be presented to the mind; as, five dots in a line are a schema of the number five; a preceding and succeeding event are a schema of cause and effect" (Websters).