What is "xsd"

XML Schema (XSD) is a language based on the XML format for defining validation rules ("schemas") in XML format documents. It was the first schema language for XML to obtain recommendation status from W3C. This language is an alternative to the DTD, whose syntax is not based on the XML format.

It was widely used for the development of NF-e (Nota Fiscal Eletrônica).

A file containing the definitions in the XML Schema language is called XSD (XML Schema Definition), this describes the structure of an XML document.

Statement of elements

The elements are declared using the "element" tag. The main attributes of the tag are:

• name: specifies the name of the element
• type: specifies the data type of the element
• minOccurs: specifies the minimum times the element can appear
• maxOccurs: specifies as many times as the element can appear (the unbounded word can be used to specify an unlimited amount).

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