Author: phd
Date: 2007-09-26 08:31:47 -0600 (Wed, 26 Sep 2007)
New Revision: 2989
Modified:
SQLObject/branches/0.8/docs/Inheritance.txt
Log:
Updated Inheritance docs.
Modified: SQLObject/branches/0.8/docs/Inheritance.txt
===================================================================
--- SQLObject/branches/0.8/docs/Inheritance.txt 2007-09-26 14:31:36 UTC (rev 2988)
+++ SQLObject/branches/0.8/docs/Inheritance.txt 2007-09-26 14:31:47 UTC (rev 2989)
@@ -282,7 +282,7 @@
Limitations and notes
~~~~~~~~~~~~~~~~~~~~~
-* Only simple inheritance will work. It is not possible to inherit
+* Only single inheritance will work. It is not possible to inherit
from multiple SQLObject classes.
* It is possible to inherit from an inherited class and this will
work well. In the above example, you can have a Chief class that
@@ -297,6 +297,18 @@
set lazyUpdate to True. If you need this, you have to patch SQLObject
and override many methods - _SO_setValue(), sync(), syncUpdate() at
least. Patches will be gladly accepted.
+* You'd better restrain yourself to simple use cases. The inheritance
+ implementation is easiliy choked on more complex cases.
+* A join between tables inherited from the same parent produces incorrect
+ result due to joins to the same parent table (they must use different
+ aliases).
+* Inheritance works in two stages - first it draws the IDs from the parent
+ table and then it drwas the rows from the children tables. The first
+ stage could fail if you try to do complex things. For example,
+ Children.select(orderBy=Children.q.column, distinct=True)
+ could fail because at the first stage inheritance generates a SELECT
+ query for the parent table with ORDER BY the column from the children
+ table.
* I made it because I needed to be able to have automatic
inheritance with linked tables.
* This version works for me; it may not work for you. I tried to do
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