Generate XSD from XML

There are several tools out there to create (or to infer) an XSD schema from XML document. I liked trang command line tool the most. Found it first when reading about Spring web services in Spring in Action book (very good book btw).

Here are four simple steps how to create XSD from XML* using trang:

Step 1. Get trang

Download trang.zip from here (at the moment of writing “trang-20030619.zip”)

Step 2. Extract it

Use “unzip trang-version.zip”, or just winzip/winrar/7z etc.. if on windows

Step 3. Make an alias

This step is optional, but makes it extremely easy to run the tool with a single command. Make an alias to the “trang.jar” by (in my case Ubuntu/Linux) editing “~/.bashrc” and adding the following:

# execute trang.jar (create XSD from XMLs)
alias xml2xsd='java -jar ~/soft/utils/trang/trang-20030619/trang.jar'

above “~/soft/utils/trang” is the directory where “trang” was unzipped to.

Step 4. Create XSD from XML

Let’s look at the XML file we need an XSD for:

$ ls -l
total 4
-rw-r--r-- 1 user group 357 2008-05-28 15:38 holiday-request.xml
 
$ cat holiday-request.xml
<?xml version="1.0" encoding="UTF-8"?>
<holidayRequest xmlns="http://mycompany.com/hr/schemas">
    <holiday>
        <startDate>2006-07-03</startDate>
        <endDate>2006-07-07</endDate>
    </holiday>
    <employee>
        <number>42</number>
        <firstName>Ultimate</firstName>
        <lastName>Answer</lastName>
    </employee>
</holidayRequest>

now run the tool against it:

$ xml2xsd holiday-request.xml hr.xsd
$ cat hr.xsd
<?xml version=”1.0″ encoding=”UTF-8″?>
<xs:schema xmlns:xs=”http://www.w3.org/2001/XMLSchema” elementFormDefault=”qualified” targetNamespace=”http://mycompany.com/hr/schemas” xmlns:schemas=”http://mycompany.com/hr/schemas”>
  <xs:element name=”HolidayRequest”>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref=”schemas:Holiday”/>
        <xs:element ref=”schemas:Employee”/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name=”Holiday”>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref=”schemas:StartDate”/>
        <xs:element ref=”schemas:EndDate”/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name=”StartDate” type=”xs:NMTOKEN”/>
  <xs:element name=”EndDate” type=”xs:NMTOKEN”/>
  <xs:element name=”Employee”>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref=”schemas:Number”/>
        <xs:element ref=”schemas:FirstName”/>
        <xs:element ref=”schemas:LastName”/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name=”Number” type=”xs:integer”/>
  <xs:element name=”FirstName” type=”xs:NCName”/>
  <xs:element name=”LastName” type=”xs:NCName”/>
</xs:schema>

done!

$

* – NOTE: “trang” can create an XSD from multiple XML documents, not just one.


List of other tools to use as an alternative to trang:

XSD away, Good Luck!