Indexes

I'm trying to perform a massive load on a postgreSQL database from ODBC,
but I've found that if the table contains a 'PRIMARY KEY' constraint, the
sql-insert sentences from my program fail. I've also noticed that after
creating the table, the ODBC driver (unixODBC) warnings me this way:

NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index for table

so I think if I could `deactivate' the index before doing the massive
load it could possibly work, but I can't find the way of deactivating
indexes looking at the documentation. Can this be done? If not, any idea
about another suitable solution?

Creating the PRIMARY KEY constraint after the massive load won't work,
because postgreSQL 7.1.3 doesn't implement the ALTER TABLE ... ADD
CONSTRAINT sentence with this kind of constraint.

Thank you very much in advance.

Laura Castro