How to identify parent without child

Question

Hello everyone,

In a  RelationshipClass  between a FC (Parent) and a Table (child)  How can I identify the aren't that do not have a child, or features in the Fc that do not have records associated in the table.

Thanks

JakeSkinner · Answer

Hi Jose, You could do this using Python. Ex: import arcpy from arcpy import env env.workspace = r"C: emp\python est.gdb" parentLayer = 'Airports' childLayer = 'Districts' # Get list of foreign keys foreignKey = [row[0] for row in arcpy.da.SearchCursor(childLayer, ["FCC"])] # Convert list to tuple primaryKey = () for id in foreignKey: primaryKey += (str(id) ,) # Search for primary keys that are not in foreignKey tuple and print OBJECTID query = "NOT FCC IN {0}".format(primaryKey) noChildIds = [row[0] for row in arcpy.da.SearchCursor(parentLayer, ["OBJECTID"], query)] print(noChildIds)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍