It also declares any attributes, entities, notations, processing instructions, comments, and PE references in the document.
The middle part of Figure 1 illustrates the SAX approach to parsing.
The downside of this approach is that keeping track of the current context of an element or attribute in a complex document can be difficult.
This can present a real problem when document sizes become too large to fit in memory in an efficient manner. The SAX parser uses a streaming model that moves through a document piece by piece and doesn't retain a copy of the nodes once they are traversed.
A client implements a set of interfaces that are called by the parser when it passes over nodes in the document.
The client access methods allow forward and backward movement, much like the client-side, static cursor in ADO data access on the Microsoft platform.
The cost of this type of capability is the resource requirements needed to keep each node in memory. The SAX API was one of the first attempts in the XML community to solve the problem of parsing large XML documents.The previous article in this series discussed the DOM API for XML data access in the . It models an XML document as a tree of nodes kept in memory while a client is using the document.The top part of Figure 1 shows how the DOM parser produces a tree of nodes.Val_Auto: The parser will report validation errors only if a grammar is specified.The schemes map to these feature values: Val_Never: parser- Get error count from the last parse operation.An XML document is typically parsed by an XML parser, which creates an in-memory logical data structure for navigating the document. The most common do not usually care what the tags are as long as they are well formed.