Skip to main content

Search 400 pages — tools, formats, elements, namespaces, directory, comparisons, XPath, datatypes, glossary, parse errors, schema errors, use cases, guides, blog and product.

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 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

Get started

Bring order to the XML your team can't afford to ignore.

Create a free account and get a private workspace to search, validate, diff, and monitor your XML feeds, sitemaps, schemas, and vendor integrations.

Get started freeSign in