+----------------+                   +--------------+
   |     request    |                   |    method    |
   +----------------+                   +--------------+
   | req_id         |------------------>| m_id         |
   | req_method     |                   | m_name       |
   | req_url        |--+                +--------------+
   | req_pr         |-+|
   | params         | ||
   | req_time       | ||                +---------------+
   | req_server     |-++----+           |    response   |
   | req_vhost      |-++----+-+         +---------------+
   | res            |-++----+-+-------->| res_id        |
   +----------------+ ||    | |         | res_desc      |
   +------------+     ||    | |         +---------------+
   |  protocol  |     ||    | |
   +------------+     ||    | |
   | pr_id      |<----+|    | |
   | pr_name    |      |    | |
   +------------+      |    | |
                       |    | |
   +----------+        |    | |
   |    URL   |        |    | |
   +----------+        |    | |
   | url_id   |<-------+    | |
   | url_dir  |--------+    | |
   | url_file |        |    | |
   +----------+        |    | |
                       |    | |
   +---------------+   |    | |
   |   directory   |   |    | |
   +---------------+   |    | |
 +>| dir_id        |<--+<-+<+-+-+
 | | dir_name      |      | | | |
 +-| dir_parent    |      | | | |
   +---------------+      | | | |
                          | | | |
   +------------+         | | | |
   |   server   |         | | | |
   +------------+         | | | |
   | s_id       |<--------+-+ | |
   | s_name     |         |   | |
   | s_ip       |         |   | |
   | s_docroot  |---------+   | |
   +------------+             | |
                              | |
   +------------+             | |
   |    vhost   |             | |
   +------------+             | |
   | vh_id      |<------------+ |
   | vh_name    |               |
   | vh_docroot |---------------+
   +------------+