is it possible to represent SQL RDB in XML?

Is it possi开发者_Go百科ble to represent a SQL Relational Database in XML?

That is, how would XML handle the primary key -> foriegn key relationships?

Or is it the case that XML can only represent the data in a single table?

If it is possible, what would you do in the case of a table having more than one foreign key? Which table is the parent in the hierarchical nesting since more than one other table holds the primary keys?