MRW
http://piratenpartei.ch

Piratenpartei Zürich
PC 85-112704-0

Der Politnetz Auftritt von Marc Wäckerlin Im Politnetz unterstützen

XML Kurzanleitung

XML kurz gefasst für Programmier-Profis aus anderen Bereichen, die sich einen Überblick verschaffen wollen.

XML-Struktur

<grossvater>
  <vater>
    <ich attribut="Wert des Attributkontens">
      <kind>Wert des 1. Elementknotens vom Typ "kind"</kind>
      <kind>Wert</kind>
    </ich>
    <geschwister/>
    <geschwister/>
  </vater>
</grossvater>

XPath

XPath adressiert Pfade in einem XML-Dokument.

Pfade

Ausdruck Beschreibung
knotenname Wähle alle Kindknoten des Elementknotens knotenname
/ Wähle die Dokumentwurzel (wenn ein Pfad mit / startet, ist er absolut adressiert)
vatername/kindkname Wähle alle Elementknoten kindname unter vatername
// Wähle Elementknoten in jeder Tiefe im Dokument, ausgehend vom aktuellen, die auf die Auswahl passen
. Wähle den aktuellen Knoten
self:: Wähle den aktuellen Knoten
.. Wähle den Übergeordneten Knoten
@attributname Wähle Attributknoten mit dem Namen attributname
* Wähle jeden beliebigen Elementknoten
@* Wähle jeden beliebigen Attributknoten
node() Wähle jeden beliebigen Knoten, Element oder Attribute
knoten1|knoten2 Wähle jeden Elementknoten vom Typ knoten1 und knoten2
ancestor:: Wähle alle Vorfahren in beliebiger Tiefe zum aktuellen Element
ancestor-or-self:: Wähle alle Vorfahren in beliebiger Tiefe zum aktuellen Element und das Element selbst
attribute:: Wähle alle Attribute des Elements
child:: Wähle alle Kinder des Elements
descendant:: Wähle alle Nachkommen des Elements
descendant-or-self:: Wähle alle Nachkommen des Elements und das Element selbst
following:: Wähle alles, was nach dem Schliessenden Tag des aktuellen Elements folgt
following-sibling:: Wähle alle nachfolgenden Geschwister
namespace:: Wähle alle Namensraumknoten des aktuellen Elements
parent:: Wähle den Vater des aktuellen Elements
preceding:: Wähle alles, was vor dem aktuellen Elements kommt
preceding-sibling:: Wähle alle Geschwister vor dem aktuellen Element

Eigenschaften, Bedingungen

Eigenschaft Beschreibung
[n] Wähle das n-te Element, z.B. vater/kind[1] wählt den ersten1) Knoten namens kind unter dem Knoten vater
[kind=wert] Wähle alle Elemente, deren Kind kind den Wert wert haben
[@attr] Wähle alle Elemente, die das Attribut attr haben
[@attr="wert"] Wähle alle Elemente, die das Attribut attr mit Wert wert haben

Es sind auch Ausdrücke möglich, wie last()-1, position()<3, u.s.w., z.B. in einem Buchladen alle Titel wählen von Büchern, die mehr als 35,00 kosten: /bookstore/book[price>35.00]/title.

Operatoren

Operator Funktion
+ Addition
- Subtraktion
* Multiplikation
div Division
= Gleichheit
!= Ungleichheit
< Kleiner als
<= Kleiner oder gleich
> Grösser als
>= Grösser oder gleich
or Oder
and Und
mod Modulus

XQuery

XQuery-Abfragen kann man z.B. mit xqilla ausführen (sudo apt-get install xqilla). Auf Pfade kann man mit XPath zugreifen, z.B. liefert doc("index.html")/html/body/h1 alle Titel der ersten Stufe einer HTML-Seite.

Syntax

XQuery besteht aus XPath Abfragen oder speziellen FLWOR Konstrukten aus «For, Let, Where, Order by, Return».

Wenn ein XML-Tag ausgegeben werden soll, schreibt man einfach das XML Tag, muss dann aber XQuery in geschweifte Klammern verpacken:

Beispiel (zusammenführen von alten Übersetzungen in eine neu generierte Qt-TS-Datei):

for $y in doc("translation.new")/TS/context order by $y/name
  return
    <context>
      {$y/name}
      {
        for $x in $y/message order by $x/source
          return
            <message>
              {$x/location}
              {$x/source}
              {doc("translation.old")/TS/context[name=$y/name]/message[source=$x/source]/translation}
            </message>
        }
      </context>

Kontrollfluss

FLWOR ist eine Abkürzung von "For, Let, Where, Order by, Return".

Listen: (1 to 5) oder (1, 2, 3, 4, 5)

Vergleiche allgemein: =, !=, <, <=, >, >= Vergleiche nach Wert: eq, ne, lt, le, gt, ge

Kommando Wirkung
for $x in pfad/zum/element
for $x in (10,20), $y in (100,200)
Iteriere die Variabel x (und y) durch alle passenden Elemente (und Werte)
order by sortiertag Sortiere die for-Schlaufe nac dem Wert von sorttiertag
where bedingung Beschränke die for-Schlaufe auf Werte, die der Bedingung entsprechen
return elemente Elemente, die ausgegeben werden
if (bedingung) then elemente else elemente Bedingte Rückgabe von Elementen
let $x := (1 to 5) Wert zuweisen an x, hier 1 2 3 4 5

Funktionen

declare function prefix:function_name($parameter AS datatype)
AS returnDatatype
{
 ...function code here...
}

Type is specified as XML Schema.

XML-Schema

Beispiel XML-Schema:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="note">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="to" type="xs:string"/>
        <xs:element name="from" type="xs:string"/>
        <xs:element name="heading" type="xs:string"/>
        <xs:element name="body" type="xs:string"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

Beispiel Verwendung von XML-Schema:

<?xml version="1.0"?>
<note xmlns="http://www.w3schools.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3schools.com note.xsd">
  <to>Tove</to>
  <from>Jani</from>
  <heading>Reminder</heading>
  <body>Don't forget me this weekend!</body>
</note>

Typen:

Name Funktion

Funktionen

Standardfunktionen haben den Präfix fn:, den man auch weglassen kann. fn:doc ist dasselbe, wie doc.

Name Description
Accessor Functions
fn:node-name(node) Returns the node-name of the argument node
fn:nilled(node) Returns a Boolean value indicating whether the argument node is nilled
fn:data(item.item,…) Takes a sequence of items and returns a sequence of atomic values
fn:base-uri()
fn:base-uri(node)
Returns the value of the base-uri property of the current or specified node
fn:document-uri(node) Returns the value of the document-uri property for the specified node
Error and Trace Functions
fn:error()
fn:error(error)
fn:error(error,description)
fn:error(error,description,error-object)
Example: error(fn:QName('http://example.com/test', 'err:toohigh'), 'Error: Price is too high')
Result: Returns http://example.com/test#toohigh and the string "Error: Price is too high" to the external processing environment
fn:trace(value,label) Used to debug queries
Functions on Numeric Values
fn:number(arg) Returns the numeric value of the argument. The argument could be a boolean, string, or node-set
fn:abs(num) Returns the absolute value of the argument
fn:ceiling(num) Returns the smallest integer that is greater than the number argument
fn:floor(num) Returns the largest integer that is not greater than the number argument
fn:round(num) Rounds the number argument to the nearest integer
fn:round-half-to-even() Example: round-half-to-even(0.5)
Functions on Strings
fn:string(arg) Returns the string value of the argument. The argument could be a number, boolean, or node-set
fn:codepoints-to-string(int,int,…) Returns a string from a sequence of code points
fn:string-to-codepoints(string) Returns a sequence of code points from a string
fn:codepoint-equal(comp1,comp2) Returns true if the value of comp1 is equal to the value of comp2, according to the Unicode code point collation (http://www.w3.org/2005/02/xpath-functions/collation/codepoint), otherwise it returns false
fn:compare(comp1,comp2)
fn:compare(comp1,comp2,collation)
Returns -1 if comp1 is less than comp2, 0 if comp1 is equal to comp2, or 1 if comp1 is greater than comp2 (according to the rules of the collation that is used)
fn:concat(string,string,…) Returns the concatenation of the strings
fn:string-join((string,string,…),sep) Returns a string created by concatenating the string arguments and using the sep argument as the separator
fn:substring(string,start,len)
fn:substring(string,start)
Returns the substring from the start position to the specified length. Index of the first character is 1. If length is omitted it returns the substring from the start position to the end
fn:string-length(string)
fn:string-length()
Returns the length of the specified string. If there is no string argument it returns the length of the string value of the current node
fn:normalize-space(string)
fn:normalize-space()
Removes leading and trailing spaces from the specified string, and replaces all internal sequences of white space with one and returns the result. If there is no string argument it does the same on the current node
fn:normalize-unicode()
fn:upper-case(string) Converts the string argument to upper-case
fn:lower-case(string) Converts the string argument to lower-case
fn:translate(string1,string2,string3) Converts string1 by replacing the characters in string2 with the characters in string3
fn:escape-uri(stringURI,esc-res) Example: escape-uri("http://example.com/test#car", true())
fn:contains(string1,string2) Returns true if string1 contains string2, otherwise it returns false
fn:starts-with(string1,string2) Returns true if string1 starts with string2, otherwise it returns false
fn:ends-with(string1,string2) Returns true if string1 ends with string2, otherwise it returns false
fn:substring-before(string1,string2) Returns the start of string1 before string2 occurs in it
fn:substring-after(string1,string2) Returns the remainder of string1 after string2 occurs in it
fn:matches(string,pattern) Returns true if the string argument matches the pattern, otherwise, it returns false
fn:replace(string,pattern,replace) Returns a string that is created by replacing the given pattern with the replace argument
fn:tokenize(string,pattern) Example: tokenize("XPath is fun", "\s+")
Functions for anyURI
fn:resolve-uri(relative,base)
Functions on Boolean Values
fn:boolean(arg) Returns a boolean value for a number, string, or node-set
fn:not(arg) The argument is first reduced to a boolean value by applying the boolean() function. Returns true if the boolean value is false, and false if the boolean value is true
fn:true() Returns the boolean value true
fn:false() Returns the boolean value false
Functions on Durations, Dates and Times
Component Extraction Functions on Durations, Dates and Times
fn:dateTime(date,time) Converts the arguments to a date and a time
fn:years-from-duration(datetimedur) Returns an integer that represents the years component in the canonical lexical representation of the value of the argument
fn:months-from-duration(datetimedur) Returns an integer that represents the months component in the canonical lexical representation of the value of the argument
fn:days-from-duration(datetimedur) Returns an integer that represents the days component in the canonical lexical representation of the value of the argument
fn:hours-from-duration(datetimedur) Returns an integer that represents the hours component in the canonical lexical representation of the value of the argument
fn:minutes-from-duration(datetimedur) Returns an integer that represents the minutes component in the canonical lexical representation of the value of the argument
fn:seconds-from-duration(datetimedur) Returns a decimal that represents the seconds component in the canonical lexical representation of the value of the argument
fn:year-from-dateTime(datetime) Returns an integer that represents the year component in the localized value of the argument
fn:month-from-dateTime(datetime) Returns an integer that represents the month component in the localized value of the argument
fn:day-from-dateTime(datetime) Returns an integer that represents the day component in the localized value of the argument
fn:hours-from-dateTime(datetime) Returns an integer that represents the hours component in the localized value of the argument
fn:minutes-from-dateTime(datetime) Returns an integer that represents the minutes component in the localized value of the argument
fn:seconds-from-dateTime(datetime) Returns a decimal that represents the seconds component in the localized value of the argument
fn:timezone-from-dateTime(datetime) Returns the time zone component of the argument if any
fn:year-from-date(date) Returns an integer that represents the year in the localized value of the argument
fn:month-from-date(date) Returns an integer that represents the month in the localized value of the argument
fn:day-from-date(date) Returns an integer that represents the day in the localized value of the argument
fn:timezone-from-date(date) Returns the time zone component of the argument if any
fn:hours-from-time(time) Returns an integer that represents the hours component in the localized value of the argument
fn:minutes-from-time(time) Returns an integer that represents the minutes component in the localized value of the argument
fn:seconds-from-time(time) Returns an integer that represents the seconds component in the localized value of the argument
fn:timezone-from-time(time) Returns the time zone component of the argument if any
fn:adjust-dateTime-to-timezone(datetime,timezone) If the timezone argument is empty, it returns a dateTime without a timezone. Otherwise, it returns a dateTime with a timezone
fn:adjust-date-to-timezone(date,timezone) If the timezone argument is empty, it returns a date without a timezone. Otherwise, it returns a date with a timezone
fn:adjust-time-to-timezone(time,timezone) If the timezone argument is empty, it returns a time without a timezone. Otherwise, it returns a time with a timezone
Functions Related to QNames
fn:QName()
fn:local-name-from-QName()
fn:namespace-uri-from-QName()
fn:namespace-uri-for-prefix()
fn:in-scope-prefixes()
fn:resolve-QName()
Functions on Nodes
fn:name()
fn:name(nodeset)
Returns the name of the current node or the first node in the specified node set
fn:local-name()
fn:local-name(nodeset)
Returns the name of the current node or the first node in the specified node set - without the namespace prefix
fn:namespace-uri()
fn:namespace-uri(nodeset)
Returns the namespace URI of the current node or the first node in the specified node set
fn:lang(lang) Returns true if the language of the current node matches the language of the specified language
fn:root()
fn:root(node)
Returns the root of the tree to which the current node or the specified belongs. This will usually be a document node
Functions on Sequences
General Functions on Sequences
fn:index-of((item,item,…),searchitem) Returns the positions within the sequence of items that are equal to the searchitem argument
fn:remove((item,item,…),position) Returns a new sequence constructed from the value of the item arguments - with the item specified by the position argument removed
fn:empty(item,item,…) Returns true if the value of the arguments IS an empty sequence, otherwise it returns false
fn:exists(item,item,…) Returns true if the value of the arguments IS NOT an empty sequence, otherwise it returns false
fn:distinct-values((item,item,…),collation) Returns only distinct (different) values
fn:insert-before((item,item,…),pos,inserts) Returns a new sequence constructed from the value of the item arguments - with the value of the inserts argument inserted in the position specified by the pos argument
fn:reverse((item,item,…)) Returns the reversed order of the items specified
fn:subsequence((item,item,…),start,len) Returns a sequence of items from the position specified by the start argument and continuing for the number of items specified by the len argument. The first item is located at position 1
fn:unordered((item,item,…)) Returns the items in an implementation dependent order
Functions That Test the Cardinality of Sequences
fn:zero-or-one(item,item,…) Returns the argument if it contains zero or one items, otherwise it raises an error
fn:one-or-more(item,item,…) Returns the argument if it contains one or more items, otherwise it raises an error
fn:exactly-one(item,item,…) Returns the argument if it contains exactly one item, otherwise it raises an error
Equals, Union, Intersection and Except
fn:deep-equal(param1,param2,collation) Returns true if param1 and param2 are deep-equal to each other, otherwise it returns false
Aggregate Functions
fn:count((item,item,…)) Returns the count of nodes
fn:avg((arg,arg,…)) Returns the average of the argument values
fn:max((arg,arg,…)) Returns the argument that is greater than the others
fn:min((arg,arg,…)) Returns the argument that is less than the others
fn:sum(arg,arg,…) Returns the sum of the numeric value of each node in the specified node-set
Functions that Generate Sequences
fn:id((string,string,…),node) Returns a sequence of element nodes that have an ID value equal to the value of one or more of the values specified in the string argument
fn:idref((string,string,…),node) Returns a sequence of element or attribute nodes that have an IDREF value equal to the value of one or more of the values specified in the string argument
fn:doc(URI) Einlesen einer XML-Datei
fn:doc-available(URI) Returns true if the doc() function returns a document node, otherwise it returns false
fn:collection()
fn:collection(string)
Context Functions
fn:position() Returns the index position of the node that is currently being processed
fn:last() Returns the number of items in the processed node list
fn:current-dateTime() Returns the current dateTime (with timezone)
fn:current-date() Returns the current date (with timezone)
fn:current-time() Returns the current time (with timezone)
fn:implicit-timezone() Returns the value of the implicit timezone
fn:default-collation() Returns the value of the default collation
fn:static-base-uri() Returns the value of the base-uri
1) Durch einen Implenetationsfehler starten die Micro$chtrott Internet Exploder ab Version 5 mit 0 statt 1