XML Schema add unique id for several child elements

[arctushar]

I have an XML file that stores movies and their actors. There are 2 movie elements (+ their movieID attribute) that contain 2 actorID each. Each actorID also contains \[code\]known_for/movies/movie\[/code\] that also has a movieID. I have managed to make "the main" movieID to be unique and actorID to be unique within that movieID. However, I also want to make movieID inside \[code\]known_for/movies/movie\[/code\] element to be unique within their corresponding actorID. I am a bit confused on where do I need to define unique id for the \[code\]known_for/movies/movie movieID \[/code\]It probably has to go somewhere inside \[code\]<xs:element name="movies\[/code\], I'm just not too sure where exactly.This is my XML file\[code\]<?xml version="1.0" encoding="UTF-8"?><moviesxmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:noNamespaceSchemaLocation="test.xsd"><movie movieID="1"> <title>Movie 1</title> <cast> <actors> <actor actorID="1"> <name>Jack</name> <known_for> <movies> <movie movieID="1">Movie 1</movie> <movie movieID="2">Movie 2</movie> <movie movieID="3">Movie 3</movie> </movies> </known_for> </actor> <actor actorID="2"> <name>James</name> <known_for> <movies> <movie movieID="1">Movie 1</movie> <movie movieID="2">Movie 2</movie> <movie movieID="3">Movie 3</movie> </movies> </known_for> </actor> </actors> </cast></movie><movie movieID="2"> <title>Movie 2</title> <cast> <actors> <actor actorID="1"> <name>Jack</name> <known_for> <movies> <movie movieID="1">Movie 1</movie> <movie movieID="2">Movie 2</movie> <movie movieID="3">Movie 3</movie> </movies> </known_for> </actor> <actor actorID="2"> <name>James</name> <known_for> <movies> <movie movieID="1">Movie 1</movie> <movie movieID="2">Movie 2</movie> <movie movieID="3">Movie 3</movie> </movies> </known_for> </actor> </actors> </cast></movie></movies>\[/code\]This is my schema\[code\]<?xml version="1.0" encoding="UTF-8"?><xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified"> <xs:element name="movies"> <xs:complexType> <xs:sequence> <xs:element name="movie" type="movieType" maxOccurs="unbounded"> <xs:unique name="unique_actorID"> <xs:selector xpath="cast/actors/actor"/> <xs:field xpath="@actorID"/> </xs:unique> </xs:element> </xs:sequence> </xs:complexType> <xs:unique name="unique_movieID"> <xs:selector xpath="movie"/> <xs:field xpath="@movieID"/> </xs:unique> </xs:element> <xs:complexType name="movieType"> <xs:sequence> <xs:element name="title" type="xs:string"/> <xs:element name="cast" type="castType"/> </xs:sequence> <xs:attribute name="movieID" type="xs:integer" use="required"/> </xs:complexType> <xs:complexType name="castType"> <xs:sequence> <xs:element name="actors" type="actorsAll"> </xs:element> </xs:sequence> </xs:complexType> <xs:complexType name="actorsAll"> <xs:sequence> <xs:element name="actor" type="actorType" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> <xs:complexType name="actorType"> <xs:sequence> <xs:element name="name" type="xs:string"/> <xs:element name="known_for" type="known_forGroup" minOccurs="0"/> </xs:sequence> <xs:attribute name="actorID" type="xs:integer" use="required"/> </xs:complexType> <xs:complexType name="known_forGroup"> <xs:sequence> <xs:element name="movies" type="known_forType"/> </xs:sequence> </xs:complexType> <xs:complexType name="known_forType"> <xs:sequence> <xs:element name="movie" type="known_forMovies" maxOccurs="unbounded"> </xs:element> </xs:sequence> </xs:complexType> <xs:complexType name="known_forMovies"> <xs:simpleContent> <xs:extension base="xs:string"> <xs:attribute name="movieID" type="xs:integer"/> </xs:extension> </xs:simpleContent> </xs:complexType></xs:schema>\[/code\]