Restriction element is used to define accepted values that an XML element can take.
Syntax
<xs:restriction base = "element-type"> restrictions </xs:restriction>
| base | Type of the Element on which restriction is to be applied. For example,<xs:restriction base = “xs:integer”> specifies that this restriction is specific to an element of type int. |
| restriction | restriction is normally a range of conditions to be applied on the element’s value. In this example, we’ve set a restriction on marks that marks should be in range of 0 to 100 with both values are included.<xs:minInclusive value = “0”/> <xs:maxInclusive value = “100”/> |
Examples
Restriction on Value.
Condition − Marks should be in range of 0 to 100.
<xs:element name = "marks">
<xs:simpleType>
<xs:restriction base = "xs:integer">
<xs:minInclusive value = "0"/>
<xs:maxInclusive value = "100"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
Restriction on Set of Values.
Condition − Grades should only be A, B or C.
<xs:element name = "grades">
<xs:simpleType>
<xs:restriction base = "xs:string">
<xs:enumeration value = "A"/>
<xs:enumeration value = "B"/>
<xs:enumeration value = "C"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
Restriction using regular pattern.
Condition − firstname should be in alphabets only.
<xs:element name = "firstname">
<xs:simpleType>
<xs:restriction base = "xs:string">
<xs:pattern value = "[a-z]"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
Types of Restrictions
| S.No. | Restriction & Description |
|---|---|
| 1 | enumerationDefines a list of values which are acceptable. |
| 2 | fractionDigitsDefines the maximum number of decimal places allowed(zero or more). |
| 3 | lengthDefines length in terms of characters of string or items in a list(zero or more). |
| 4 | maxExclusiveDefines upper bounds for numeric values excluding this number. |
| 5 | maxInclusiveDefines upper bounds for numeric values including this number. |
| 6 | maxLengthDefines maximum length in terms of characters of string or items in a list(zero or more). |
| 7 | minExclusiveDefines lower bounds for numeric values excluding this number. |
| 8 | minInclusiveDefines lower bounds for numeric values including this number. |
| 9 | minLengthDefines minimum length in terms of characters of string or items in a list(zero or more). |
| 10 | patternDefines the exact sequence of characters identified by the pattern that are acceptable |
| 11 | totalDigitsDefines the exact number of digits allowed in the number(always greater than zero) |
| 12 | whiteSpaceDefines the way in which white space characters (line feeds, tabs, spaces, and carriage returns) are handled |
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