NULL value vs. DEFAULT value.

version = postgresql-8.4.4-2PGDG.el5.src.rpm

I am seeing this problem and I cannot explain why it is happening.
Evidently I misapprehend something about the interaction of NOT NULL
and DEFAULT.  If someone could tell me what the actual case is I
would appreciate it very much.

The table definition looks like this:
CREATE TABLE ca_customs_shipments (
    id integer NOT NULL,
.  .  .
    weight_mass_gross numeric(14,4) DEFAULT 0.0 NOT NULL,
    weight_mass_gross_uom character varying(3)
      DEFAULT '   '::character varying NOT NULL,
    weight_mass_net numeric(14,4) DEFAULT 0 NOT NULL,
    weight_mass_net_uom character varying(3)
      DEFAULT '   '::character varying NOT NULL,
.  .  .
);


My question is:  Why am I getting a NULL exception?  Should I only
specify DEFAULT and drop the NOT NULL constraint?


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James B. Byrne                mailto:ByrneJB@Harte-Lyne.ca
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