Chapter 17¶
Identity constraints¶
Binding Test¶
Schema
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:annotation>
<xsd:documentation>
This example illustrates identity constraints. Each child of items must have a number attribute whose value is unique within order. All product descendents of order must have a number child whose value matches one of these unique product numbers.
</xsd:documentation>
</xsd:annotation>
<xsd:element name="order" type="OrderType">
<xsd:keyref name="prodNumKeyRef" refer="prodNumKey">
<xsd:selector xpath="items/*"/>
<xsd:field xpath="@number"/>
</xsd:keyref>
<xsd:key name="prodNumKey">
<xsd:selector xpath=".//product"/>
<xsd:field xpath="number"/>
</xsd:key>
</xsd:element>
<xsd:complexType name="OrderType">
<xsd:sequence>
<xsd:element name="number" type="xsd:string"/>
<xsd:element name="items" type="ItemsType"/>
<xsd:element name="products" type="ProductsType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="ItemsType">
<xsd:choice maxOccurs="unbounded">
<xsd:element name="shirt" type="ProductOrderType"/>
<xsd:element name="hat" type="ProductOrderType"/>
</xsd:choice>
</xsd:complexType>
<xsd:complexType name="ProductOrderType">
<xsd:sequence>
<xsd:element name="quantity" type="xsd:integer"/>
<xsd:element name="color" type="ColorType" minOccurs="0"/>
</xsd:sequence>
<xsd:attribute name="number" type="xsd:integer"/>
</xsd:complexType>
<xsd:complexType name="ProductsType">
<xsd:sequence>
<xsd:element name="product" type="ProductType" maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="ProductType">
<xsd:sequence>
<xsd:element name="number" type="xsd:integer"/>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="price" type="PriceType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="ColorType">
<xsd:attribute name="value" type="xsd:string"/>
</xsd:complexType>
<xsd:complexType name="PriceType">
<xsd:simpleContent>
<xsd:extension base="xsd:decimal">
<xsd:attribute name="currency" type="xsd:token"/>
</xsd:extension>
</xsd:simpleContent>
</xsd:complexType>
</xsd:schema>
XML Document
<order xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="chapter17.xsd">
<number>123ABBCC123</number>
<items>
<shirt number="557">
<quantity>1</quantity>
<color value="blue"/>
</shirt>
<shirt number="557">
<quantity>1</quantity>
<color value="sage"/>
</shirt>
<hat number="563">
<quantity>1</quantity>
</hat>
</items>
<products>
<product>
<number>557</number>
<name>Short-Sleeved Linen Blouse</name>
<price currency="USD">29.99</price>
</product>
<product>
<number>563</number>
<name>Ten-Gallon Hat</name>
<price currency="USD">69.99</price>
</product>
</products>
</order>
xsData XML Document
<order>
<number>123ABBCC123</number>
<items>
<shirt number="557">
<quantity>1</quantity>
<color value="blue"/>
</shirt>
<shirt number="557">
<quantity>1</quantity>
<color value="sage"/>
</shirt>
<hat number="563">
<quantity>1</quantity>
</hat>
</items>
<products>
<product>
<number>557</number>
<name>Short-Sleeved Linen Blouse</name>
<price currency="USD">29.99</price>
</product>
<product>
<number>563</number>
<name>Ten-Gallon Hat</name>
<price currency="USD">69.99</price>
</product>
</products>
</order>
xsData JSON
{
"number": "123ABBCC123",
"items": {
"shirt": [
{
"quantity": 1,
"color": {
"value": "blue"
},
"number": 557
},
{
"quantity": 1,
"color": {
"value": "sage"
},
"number": 557
}
],
"hat": [
{
"quantity": 1,
"color": null,
"number": 563
}
]
},
"products": {
"product": [
{
"number": 557,
"name": "Short-Sleeved Linen Blouse",
"price": {
"value": "29.99",
"currency": "USD"
}
},
{
"number": 563,
"name": "Ten-Gallon Hat",
"price": {
"value": "69.99",
"currency": "USD"
}
}
]
}
}
Example 17-13 Referencing an identity constraint in a restriction¶
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://datypic.com/prod" xmlns="http://datypic.com/prod" xpathDefaultNamespace="http://datypic.com/prod">
<xs:include schemaLocation="../chapter15/example1515.xsd" />
<xs:complexType name="CatalogListType">
<xs:sequence>
<xs:element name="catalog" type="CatalogType" maxOccurs="unbounded">
<xs:unique name="dateAndProdNumKey">
<xs:selector xpath="department/product" />
<xs:field xpath="number" />
<xs:field xpath="@effDate" />
</xs:unique>
</xs:element>
</xs:sequence>
</xs:complexType>
<xs:complexType name="RestrictedCatalogListType">
<xs:complexContent>
<xs:restriction base="CatalogListType">
<xs:sequence>
<xs:element name="catalog" type="CatalogType" maxOccurs="1">
<xs:unique ref="dateAndProdNumKey" />
</xs:element>
</xs:sequence>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
</xs:schema>
from dataclasses import dataclass, field
from typing import List, Optional
from tests.fixtures.defxmlschema.chapter15.example1515 import (
CatalogType,
)
__NAMESPACE__ = "http://datypic.com/prod"
@dataclass
class CatalogListType:
"""
:ivar catalog:
"""
catalog: List[CatalogType] = field(
default_factory=list,
metadata=dict(
type="Element",
namespace="",
min_occurs=1,
max_occurs=9223372036854775807
)
)
@dataclass
class RestrictedCatalogListType:
"""
:ivar catalog:
"""
catalog: Optional[CatalogType] = field(
default=None,
metadata=dict(
type="Element",
namespace="",
required=True
)
)
Samples Source
Definitive XML Schema by Priscilla Walmsley (c) 2012 Prentice Hall PTR