Restriction types in XML Schema
Posted in
XML | DTD July 06, 2019
This article describe about several type of restrictions in XML Schema
Other Restrictions on a Series of Values
In XML schema also different technique to take restriction. These are given below which accept the value is ZERO or MORE occurrence of LOWERCASE letter from a to z.
<xs:element name="Messsage">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="([a-z])*"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
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Note: Above declared element "Message" take restriction on schema.
Example 2
<xs:element name="Message">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="([a-z][A-Z])+"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
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Note: Second example also defines an element called "Message" with a restriction. This element accept value is one or more pairs of letter, each pair consist of a lower case letter followed by an upper case letter. For example, "sTART" must be validated by this pattern, but not "Start" or "START" or "start":
Example 3
Note: Third example show that an element "Sex" with some restriction. It is only accept value male Or female:
<xs:element name="Sex">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="male|female"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
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Example 4
<xs:element name="password">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9]{7}"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
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Note: This example show that an element "password" declared with some restriction. It take "7" character long password weather in lowercase or uppercase from "a" to "z" or number from 0 to 8.
Restrictions on Whitespace Characters
In this topic define how whitespace characters should be handled, For this we have to use the whitespace constraint.
<xs:element name="location">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:whiteSpace value="preserve"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
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Note: The above declared example called "location" with some restriction. The whitespace constraint is set to "preserve" this means XML processor will not remove any whitespace.
Example 1
<xs:element name="location">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:whiteSpace value="replace"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
|
Note: This example also define an element called "location" with a restriction. The whitespace constraint is set to "replace" this means that XML processor will "REPLACE" if any whitespace occur either in character or line or paragraph.
Example 2
<xs:element name="location">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:whiteSpace value="collapse"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
|
Note: This is also another example define an element called "location" with a restriction. The whitespace constraint is set to "collapse" this means that XML processor will "REMOVE" all whitespace characters (tabs, multi-line space, single-line space etc.
Further Readings
You may also want to read these related articles :
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