XSQL uses a simple schema to represent SQL in XML format. The DTD is below: <!ELEMENT sql:sql(sql:connect)> <!ATTLIST sql:sql xmlns:sql ”http://www.openhealth.org/xsql" #FIXED> <!ELEMENT sql:connect (sql:uid|sql:insert|sql:update|sql:delete|sql:select)*> <!ATTLIST sql:connect database CDATA #REQUIRED> <!ELEMENT sql:select (sql:where|sql:column|sql:all|sql:table)*> <!ELEMENT sql:all EMPTY> <!ELEMENT sql:table EMPTY> <!ATTLIST sql:table name NMTOKEN #REQUIRED>