Notes about revision architecture

NewDocumentEditor.wiki

diff --git a/NewDocumentEditor.wiki b/NewDocumentEditor.wiki
index 5ccff9c..7622a12 100644
--- a/NewDocumentEditor.wiki
+++ b/NewDocumentEditor.wiki
@@ -11,20 +11,38 @@
   # Minimize the size of the data retrieved.
   # Minimize datastore queries and simplify them.
 
-Here is the prototypes of models:
+== First approach: independent revisions ==
 {{{
-from google.appengine.ext import db
-class DocRevision(db.Model):
-  user = db.UserProperty() # User, who has created the revision
-  created = db.DateTimeProperty() # Date and time of creation
-  doc = db.ReferenceProperty() # Document entity reference
-
 class Revision(db.Model):
-  revs = db.LinkProperty(db.Key) # List of DocRevision keys
-  public = db.LinkProperty(db.Key) # List of keys to public revisions
-  private = db.LinkProperty(db.Key) # List of keys to private revisions
+  revision_id = db.IntegerProperty()
+  timestamp = db.DateTimeProperty() # It's not required, cause Document entity has it
+  user = db.UserProperty() # It's not required, cause Document entity has it
+  comment = db.TextProperty() # Comment about the revision
+  current = db.BooleanProperty() # Current revision
+  deleted = db.BooleanProperty() # Revision is marked as deleted
+  public = db.BooleanProperty() # Public or private revision
+  document = db.ReferenceProperty() # Reference to content
 }}}
 
+It's obvious that revisions are not linked to each other. Each operation on revision is just a query to a datastore.
+
+== Second approach: Linked revisions ==
+{{{
+class DocRevision(db.Model):
+  revision_id = db.IntegerProperty() # It's necessary for list rearrangement
+  timestamp = db.DateTimeProperty() # It's not required, cause Document entity has it
+  user = db.UserProperty() # It's not required, cause Document entity has it
+  comment = db.TextProperty() # Comment about the revision
+  document = db.ReferenceProperty() # Reference to content
+
+class Revision(db.Model):
+  revisions = db.ListProperty(db.Key) # List of revisions
+  public = db.ListProperty(db.Key)
+  private = db.ListProperty(db.Key)
+}}}
+
+This approach helps to manage revisions easily, but list rearrangement operations consumes expensive CPU time.
+ 
 This approach allows us to simplify revision management. {{{revs}}}, {{{public}}} and {{{private}}} are manged at entity creation.
 = Project timeline =
 == Week 1 (24 May - 30 May) ==