You have now seen how to link data together based on a common key field using a Join or Relate, based on a spatial relationship. These methods are extremely useful. However, they do have limitations. Joins and Relates only exist in a single map and do not transfer easily to other maps or projects. Spatial Joins create new feature classes or tables while still leaving the original data unaltered. So, is there a way to permanently link two tables or two feature classes together?
The answer is yes, if the data is all in the same geodatabase. In a geodatabase, you can create a relationship class. A relationship class permanently links data together and the link carries over into any map, scene, or project you use the data in. You can create a relationship class between two feature classes, two standalone tables, or a feature class and a standalone table.
Relationship classes provide greater flexibility than the other methods we have looked at in previous recipes...