how to assert into the db with rdbms

Hello,

I have just started to explore the possibilities of the RDBMS system.

Querying the DB works with some minor problems using sbcl+clsql+mysql.

But, how can I assert facts into the database?

I found create-sql-assertion-from-proposition and a
db-relation-update-demon in the code, but cannot figure out, how they
might be useful to store sth in the database.

Another problem is: I can use defquery to define queries involving one
single table, but I don't manage to define sql table joins correctly.

Would you be so kind to provide an example for these two uses of
rdbms:

1) asserting facts into the DB

2) defquery with an SQL join


Many thanks for your help!


Kambiz