Materialized path and SQL query explaination
===

i am reading this article about saving trees into database <br />
http://www.dba-oracle.com/t_sql_patterns_trees.htm
But i don't understand for example this <br />

    select e1.ename from emp e1, emp e2
    where e1.path like e2.path || '%'
    and e2.ename = 'JONES'

What does mean  this: `e1.path like e2.path || '%'`

I don't understand using boolean operator in that query. I know '%' is (.*) in reqular expression. Its looks for me like: `(e1.path == e2.path) or (e1.path == whateverIWant)`.
Thx for hlp. 