I'm working on a product information manager, and I have a content type of product which needs to reference stock and price levels for each supplier from a different database - these are stored as separate sqlite databases (one for each supplier) and managed outside of drupal.

I would like to reference the prices and stock levels without actually importing them all into the drupal database, instead pulling from the external database, but I'm a little confused how to structure this? One product can have many suppliers.

Do I need a separate entity to manage the pulling of the data (possibly one entity for each supplier) then somehow attach to the product node (manufacturer and part number would be used to search the supplier db), or, would it be considered a field, or a module with options set specifying the database location for each content type. Each product node shouldn't have to specify its list of suppliers.

The data would need to be shown when a node is displayed - I would like the data to be accessible from within views, but also searchable, e.g. display products where stock level < 3 for supplier xyz.

I'm thinking an entity wouldn't be correct as an input of manufacturer and part number would be needed before the data can be pulled?