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XML Schema (XSD)

<xs:restriction>

Derives a narrower type from a base by applying compatible facets or restricting a content model.

Inside simpleType, restriction starts with a base datatype and adds facets. Every accepted value must remain valid in the base type.

Facet availability depends on the base: minLength applies to strings and lists, while minInclusive applies to ordered values.

Format
XML Schema (XSD)
Namespace
XML Schema Definition (XSD)
Parent
<xs:simpleType>
How many
Exactly one when a simple type uses the restriction variety.

What it contains

  • facet elementsany numberFor example enumeration, pattern, or minLength.

Attributes

  • baserequiredA QName naming the datatype whose value space is narrowed.

Cardinality and constraints

Exactly one when a simple type uses the restriction variety.

  • The base must identify a simple type here.
  • Only facets allowed for the base datatype may appear.

What our validator does

The XML validator checks well-formedness and selected SOAP or XML Schema vocabulary rules. It reports this content-model defect with a concrete repair while staying silent on rules it cannot establish from one document.

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>
xs:attribute cannot use minOccurs or maxOccurs; attributes use the use attribute instead.
fixed
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="urn:example:catalog" 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="tns:Sku"/></xs:sequence><xs:attribute name="active" type="xs:boolean"/></xs:complexType>
  <xs:element name="product" type="tns: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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