This answer might not be related to yours but i thought it should be helpful for others who are working with android database.
IN SQLite Foreign key constraints are disabled by default (for backwards compatibility). You have to enable it explicitly using
PRAGMA foreign_keys = 1
after you establishing your connection with the database.
Here’s the link to the official docs that explains it in more depth.
http://sqlite.org/foreignkeys.html
Please navigate to enabling foreign key support in the above link.