What is on the first line of an XML Schema (XSD)? -

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so before write xml schema, lot of tutorials use this:

 <?xml version='1.0'?>

or

 <?xml version="1.0" encoding="utf-8" standalone="yes"?>  <data-set xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">

my question is, part for? website , why use it? there other methods this?

if helps, doing convert excel worksheet xml.

xml declaration

<?xml version='1.0'?> xml declaration , not particular xsds xml documents in general.

[definition: xml documents should begin xml declaration specifies version of xml being used.]

as xsd xml document, may have xml declaration.

here bnf of xml declaration (xmldecl) links definitions of constituent parts:

xmldecl ::= '<?xml'versioninfo encodingdecl? sddecl? s? '?>'

note: only 1 xml declaration permitted in well-formed xml, , must @ top if anywhere. if violate requirement, you'll see error such

the processing instruction target matching "[xx][mm][ll]" not allowed.

and you'll have fix problem before xml well-formed.

xml schema instance namespace

xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" namespace declaration special xml schema instance namespace. namespace uri, it's purpose facilitate control of grouping of component name. an xml namespace uri not have retrievable.

see also


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