GIS Join - Flat Data File To Georeferenced Point, Line or Polygon

Geocoding a data tableau with a georeferenced polygon file. This example has a national database of 5 digit ZIP codes. An XLS spreadsheet has a small list of ZIP codes for one county. The XLS data file has only a few attributes. Using the common field of 5 digit ZIP, the two are joined thereby making the flat file data tableau to be geospatial.