Parameters declarations should be described in the <header> section of the updategram. There should be one <param> row for each parameter.

General syntax:

<sql:header xmlns:sql="xml-sql">
  <sql:param name="PARAM_NAME" [default="DEFAULT_VALUE"]/>

Where PARAM_NAME is the name of the parameter and DEFAULT_VALUE is optional default of parameter Parameters in updategram should have $PARAM_NAME instead of a value. On processing, Virtuoso replaces $PARAM_NAME with the corresponding value from the <input_parameters> given to the function xmlsql_update() .