We would need to know much more details about your requirements and how the information is related, to be able to answer your question.

The common link between the two databases is the zip code – does this help?

generally speaking, you are referring to GIS mapping coordinates. Lattitudes and longitudes (also include alttitude) are spatial object s, representing points and are captured from satelite signal using a GIS receiver, converted to 2 dimensional points and finally to pixel points on the flat screen and representing Points (x, y coordinates) on the flat map. A series of ordered points can represent a polygon (boundaries – eg country or area), a line (eg. road, river etc). A point ( x,y coordinates) can also be a node (represent a intersection, junction of roads. A point represent a location eg city, towns, address etc.

As for your question, if you think you need to use the logitudes/lattitude data wih your business info and turn into an application,, then merge them. To merge them, look for the common denominator, ie. a field which is common to both, and then create relevant tables in the business database to import the longitude/lattitude data into.The common field is the link between the coordinates and the business info. More importantly, you need to create an application out of this merger

it may interest you to find out what the coordinates represent. Try using a google map(of your country) and plot the points on it. You may be suprsed at what yousee.