how to drop hsql constraint

i've been searching from google for hours now but i still can't seem to find out how to delete an fk constraint in hsql. can anyone help

[edit]
well i figured it out after i just posted for those who wants to know first

"ALTER TABLE <tablename> DROP CONSTRAINT <constraintname>"

to find the constraint check for in the hsql db script with the

...
ALTER TABLE <tablename> ADD CONSTRAINT <constraintname>
...

this then remove the constraint and allows you to drop the column as normal

ALTER TABLE <tablename> DROP column <columnname>