I think, this is the problem of sqlite.
Just found it in http://sqlite.org/omitted.html
Very first item says:
---
FOREIGN KEY constraints are parsed but are not enforced. However, the equivalent constraint enforcement can be achieved using triggers. The SQLite source tree contains source code and documentation for a C program that will read an SQLite database, analyze the foreign key constraints, and generate appropriate triggers automatically.
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It is very likely that my initial classes were correct (just ForeignKey), and also the database schema is correctly created by sqlobject.
 
Zoran


From: petr.jakes.tpc@gmail.com [mailto:petr.jakes.tpc@gmail.com] On Behalf Of Petr Jakeš
Sent: Thursday, January 08, 2009 12:29 PM
To: Zoran Bošnjak
Cc: sqlobject-discuss
Subject: Re: [SQLObject] FW: table ralations
 
Than maybe you can try exactly what in the example is:

child=MultipleJoin("Blocks", joinColumn="parent_id")

You can have as many children as you want (and no woman necessary ;-) )

But "one parent" only (no multiple parents - it does not work even in the real live)

If you are looking for many-to-many relationship, try this:
http://www.sqlobject.org/SQLObject.html#many-to-many-relationships