How to validate empty string value tag in xsd

I have an xml file which is having some date values and other datatypes.

<Purchasedate Name="purcaseDate" value=""/>

I am validating these xml files with a xsd file. In xsd shcema I have written a regular expression pattern for dd/mm/yyyy format.

This is working fine if value attribute have开发者_运维技巧 a value. My pattern is validating against the value attribute.

The field (purchasedate) is not mandatory. if value="", this means my pattern is validating against an empty string also, which is not mandatory.

I need to validate the optional field and i am using <xs:attribute name="PurchaseDate" use="optional"> also.

I need to validate this field when value tag is not empty.

That's too easy ..

Just all you have to do is to include empty string specification in your pattern

This is the way to do that .. <xs:pattern value="|(Regular_pattern_goes_here)"/>

For your reference I have written a sample chunks of codes .. just go through them ..

sample XML:

<?xml version="1.0" encoding="utf-8"?>
<xmln xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.example.com XMLFile1.xsd" xmlns="http://www.xsdef.com/xml/123">
  <Purchasedate Name="purcaseDate" value=""/>
</xmln>

sample XSD:(includes custom type def)

<xs:schema xmlns:xsLocal="http://www.xsdef.com/xml/123" xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.xsdef.com/xml/123" elementFormDefault="qualified" attributeFormDefault="unqualified">
  <xs:element name="xmln">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Purchasedate">
          <xs:complexType>
            <xs:simpleContent>
              <xs:extension base="xs:string">
                <xs:attribute name="Name" type="xs:string" use="required" />
                <xs:attribute name="value" type="xsLocal:CUSTOM_DATE" use="required" />
              </xs:extension>
            </xs:simpleContent>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:simpleType name="CUSTOM_DATE">
    <xs:restriction base="xs:string">
      <xs:pattern value="|((01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31)/(01|02|03|04|05|06|07|08|09|10|11|12)/[1-2][0-9][0-9][0-9])"/>
    </xs:restriction>
  </xs:simpleType>
</xs:schema>

try adding this attribute nillable="true" into the xml tag definition Also you can take a look at his link http://www.zvon.org/xxl/XMLSchemaTutorial/Output/ser_over_st0.html
Best Reagds,
Iordan

The '?' character in the Regex means that the character before it must occur 0 or 1 times.

So in order to solve your issue you need to wrap the regex in parenthesis and put a questionmark at the end:

  <xs:simpleType name="PurchaseDateType">
    <xs:restriction base="xs:string">
      <xs:pattern value="(Regular_pattern_goes_here)?"/>
    </xs:restriction>
  </xs:simpleType>

Use this type on your field and you should be fine

If you control the syntax of the XML, you should consider defining the element as follows. Since XML-Schema already provides a date type, you should use it unless you have a really good reason. I say this because it will make it easier for others to use the xml and for you to use better code frameworks later. I didn't include the "name" attribute because it seemed redundant to the element name.

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">

<xs:element name="Purchasedate" nillable="true" type="xs:date"/>
<xs:element name="Purchasedate2">
    <xs:complexType>
        <xs:attribute name="value" type="xs:date"/>
    </xs:complexType>
</xs:element>
<xs:element name="root">
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="Purchasedate"/>
            <xs:element minOccurs="0" ref="Purchasedate2"/>
        </xs:sequence>
    </xs:complexType>
</xs:element>