 
 /* ------------------------------------------------------------------------- */
 
+/* The ACTUAL_NODE table describes text changes and property changes on each
+   node in the WC, relative to the WORKING_NODE table row for the same path
+   (if present) or else to the BASE_TABLE row for the same path (which must
+   exist).
+
+   The ACTUAL_NODE table row for a given path exists iff the node at that
+   path is known to have text or property changes relative to its
+   WORKING_NODE row. ("Is known" because a text change on disk may not yet
+   have been discovered and recorded here.)
+ */
 CREATE TABLE ACTUAL_NODE (
   /* specifies the location of this node in the local filesystem */
   wc_id  INTEGER NOT NULL REFERENCES WCROOT (id),


/* ------------------------------------------------------------------------- */

CREATE TABLE WORKING_NODE (
  /* specifies the location of this node in the local filesystem */
  wc_id  INTEGER NOT NULL REFERENCES WCROOT (id),



/* ------------------------------------------------------------------------- */

/* The PRISTINE table keeps track of pristine texts. Each pristine text is
   stored in a file which may be compressed. Each pristine text is
   referenced by any number of rows in the BASE_NODE and WORKING_NODE
   tables.
 */
/* ### BH: Will CHECKSUM be the same key as used for indexing a file in the
           Pristine store? If that key is SHA-1 we might need an alternative
           MD5 checksum column on this table to use with the current delta
