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XML Schema (XSD)

<xs:sequence>

A model group requiring child particles to occur in declared order, subject to each occurrence range.

sequence models records whose children have a stable order. Optional children remain ordered relative to whichever children are present.

Occurrences on the group repeat the entire sequence; the same attributes on a child repeat only that particle.

Format
XML Schema (XSD)
Namespace
XML Schema Definition (XSD)
Parent
<xs:complexType><xs:sequence><xs:choice>
How many
Zero or one as a primary content model; model groups may nest.

What it contains

Attributes

  • minOccursoptionalDefaults to 1 and controls how often the complete sequence may occur.
  • maxOccursoptionalDefaults to 1; unbounded repeats the complete group.

Cardinality and constraints

Zero or one as a primary content model; model groups may nest.

  • Children are matched in declaration order.
  • Group occurrence constraints apply to the complete group.

What our validator does

The XML validator checks that both examples are well-formed. It does not enforce this vocabulary's semantic content model, so the broken example is intentionally reported as valid XML.

We do not catch this one

This document is well-formed XML but violates a SOAP or XML Schema vocabulary rule. XML syntax alone cannot detect that defect; use a SOAP-aware processor or an XSD validator when conformance matters.

Broken and fixed

Both documents below are well-formed XML — that is the point of this corpus — and both are run through the validator on every test run. The verdicts here are what it returned, not what we expect it to.

broken
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:example:catalog">
  <xs:complexType name="Product"><xs:attribute name="active" type="xs:boolean" maxOccurs="2"/></xs:complexType>
</xs:schema>
No issue reported. This defect passes our checks.
fixed
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:example:catalog" elementFormDefault="qualified">
  <xs:simpleType name="Sku"><xs:restriction base="xs:string"><xs:minLength value="1"/></xs:restriction></xs:simpleType>
  <xs:complexType name="Product"><xs:sequence><xs:element name="sku" type="Sku"/></xs:sequence><xs:attribute name="active" type="xs:boolean"/></xs:complexType>
  <xs:element name="product" type="Product"/>
</xs:schema>
No errors. Warnings may remain — a conforming feed can still be missing a self link — but nothing here is wrong.

Where it reaches

Related elements

All 49 elements

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