I have a database driven website with about 400 parts for sale.Some
items have been indexed and many have not.I have checked the database
for errors but found none.We just rebuilt the site with this database
so its new.Does Google need to spider it a few times to get all the
items in the database indexed?.

Hello kitesurferdude,

Let me first tell how the google works.
Google gets the info about any part on your website if there exists
any link for the parts.

If your website provides link(however deep these links exist) to all
those 400 parts certainly one crawl is enough.

otherwise you can create a page particularly having links to the all
the 400 parts. and make sure that link to this webpage is provided the
main website. This will make just one crawl to index all the items in
the database indexed.

However if you want the google to return your website for any search
of part, then there is a diffrent approach for that.

Hope this answers your question.