how to avoid sequence using XSD

i want a particular sequence to be generated in a random manner

<item>
 <i1>abc</i1>
 <i2>pqr</i2>
</item>

now how can i make an xsd where <i1> can开发者_开发百科 come before <i2> ?

use the 'all' indicator as shown on the w3schools website