Booleans

Hi,
I've written an php script with many queries like

"insert into table (a,b,c) VALUES('$q','$w','$e')"

where $q,$w and $e are booleans. I've written it with mysql and it works fine
there, now I want to use it with postgres and have the following problem:
As type for a,b and c I used the bit type with length 1. Now if $q is true
there is now problem it evaluates to '1', but false evaluates to '' and
postgres then complains that the bit string length does not match. Its
clearly why it happens, but is there an easy way to fix this, without
rewriting all the sql queries with something like if($q===false) $q='0';.

Thank you
Jascha Schubert