Is there a way to get details of the product from single insudtry?

I want to maintain a database of all the products or the brands with respect to industry. For example I need to get 开发者_运维百科information about all the food supplements. How can I get them? I am not sure all the companies have an API for their products.

Please advise

Uhm,... what kind of information? If you need prices, you can probably get information from goverment sources. At least you can here in Argentina. Other than that, I don't think it's possible, unless you somehow manage to scrape websites of all the brands you want to track.

Speaking as someone who has worked for two data-aggregation companies, aggregating data involves a lot of manual work. You find the sources, you automate the acquisition of data as best you can (APIs, file downloads and imports, even screen scraping from HTML pages), and you stay on top of it constantly. You're always looking for additional sources, updating code for sources that have changed, minding legal implications of sources who don't want you to harvest their data, etc.

Sometimes you have to buy the data, or weigh that cost against not having data from that source or scraping it manually. Sometimes a source will block you in some way and you need to either try to get around that or negotiate some terms with them. It's a viable business model, but it's not cheap.

For some products, Retailigence ( http://www.retailigence.com ) may have data in API form. They basically keep track of local stores' inventory and pricing for certain categories of products.

You should definitely check out Good Guide - an API that gives you access to details on over 60,000 household products.

http://developer.goodguide.com

DailyMed is a good service to check out if you're interested in products in the medical space.

http://dailymed.nlm.nih.gov/dailymed