Added doc notes on new database hierarchy

svn: r14111

src/gen/db/__init__.py

@@ -18,6 +18,57 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #
 
+"""
+    Gramps Database API.
+
+    Database Architecture
+    =====================
+
+    Access to the database is made through Python classes. Exactly
+    what functionality you have is dependent on the properties of the
+    database. For example, if you are accessing a read-only view, then
+    you will only have access to a subset of the methods available.
+
+    At the root of any database interface is either DbReadBase and/or
+    DbWriteBase. These define the methods to read and write to a
+    database, respectively.
+
+    The full database hierarchy is:
+
+    - B{DbBsddb} - read and write implementation to BSDDB databases (U{gen/db/write<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/write.py?view=markup>})
+        - B{DbWriteBase} - virtual and implementation-independent methods for reading data (U{gen/db/base.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/base.py?view=markup>})
+        - B{DbBsddbRead} - read-only (accessors, getters) implementation to BSDDB databases (U{gen/db/read.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/read.py?view=markup})
+            - B{DbReadBase} - virtual and implementation-independent methods for reading data (U{gen/db/base.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/base.py?view=markup})
+            - B{Callback} - callback and signal functions (U{gen/utils/callback.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/utils/callback.py?view=markup})
+        - B{UpdateCallback} - callback functionality (U{gen/updatecallback.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/read.py?view=markup gen/updatecallback.py?view=markup>})
+    - B{DbBDjango} - read and write implementation to Django-based databases (U{web/djangodb.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/web/djangodb.py?view=markup})
+        - B{DbWriteBase} - virtual and implementation-independent methods for reading data (U{gen/db/base.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/base.py?view=markup})
+        - B{DbReadBase} - virtual and implementation-independent methods for reading data (U{gen/db/base.py<http://gramps.svn.sourceforge.net/viewvc/gramps/trunk/src/gen/db/base.py?view=markup})
+
+    DbBsddb
+    =======
+
+    The DbBsddb interface defines a hierarchical database
+    (non-relational) written in
+    U{http://www.jcea.es/programacion/pybsddb.htm PyBSDDB}. There is no
+    such thing as a database schema, and the meaning of the data is
+    defined in the Python classes above. The data is stored as pickled
+    tuples and unserialized into the primary data types (below).
+
+    DbDjango
+    ========
+
+    The DbDjango interface defines the Gramps data in terms of
+    I{models} and I{relations} from the
+    U{Django project<http://www.djangoproject.com/}. The database
+    backend can be any implementation that supports Django, including
+    such popular SQL implementations as sqlite, MySQL, Postgresql, and
+    Oracle. The data is retrieved from the SQL fields, serialized and
+    then unserialized into the primary data types (below).
+
+    More details can be found in the manual's U{Using database API<http://www.gramps-project.org/wiki/index.php?title=Using_database_API>}.
+"""
+
 from base import *
 from dbconst import *
 from cursor import *