Why does ArcMap crash if I try this Join Field (which ArcPy does not like either)?

Question

• I'm a little uncertain whether this question belongs here or on http://gis.stackexchange.com

Have an "AddJoin" that results in no shared records, which is not what I'm expecting. Is it because I'm using a text field for the join? Something else? I'm trying to do this on point features from featureclass layers in a file gdb and a shapefile (both expressed as TableViews) on which I've performed a arcpy.SelectLayerByAttribute_management(). No cursors are being used.

Thanks for any ideas. ArcGIS 10.0. Also, ArcMap crashes if I try a JoinField on the same fields.

>>> arcpy.GetCount_management("GagesII")
<Result '1'>
>>> for row in arcpy.SearchCursor("GagesII"):
...     gageid=row.getValue("GAGE_ID")
...     
>>> gageid
u'01170000'
>>> arcpy.GetCount_management("StreamGageEvent")
<Result '1'>
>>> for row in arcpy.SearchCursor("StreamGageEvent"):
...     sourcefea=row.getValue("SOURCE_FEA")
...     
>>> sourcefea
u'01170000'
>>> if gageid==sourcefea:
...     print 'yes'
...     
yes
>>> 
>>> arcpy.AddJoin_management("GagesII", 'GAGE_ID', "StreamGageEvent", "SOURCE_FEA", "KEEP_COMMON")
<Result 'GagesII'>
>>> 
>>> arcpy.GetCount_management("GagesII")
<Result '-1'>

Answer 1

You say:

ArcMap crashes if I try a JoinField on the same fields

My feeling is that if it cannot be done interactively then the issue is outside of ArcPy and you should look more closely at your data.

Perhaps try working on fresh copies of your feature class and shapefile and see whether they can be joined both via the layer's context menu (which will give you an option to validate the join) and the Join Field tool.

Answer 2

I seem to have a workaround based on the recommendation of a colleague.

I'm now using "KEEP_ALL" in the AddJoin() followed by a SelectLayerByAttribute_management() where the foreign key is null.

I now see and can programmatically confirm that the appropriate subset has been selected. Seems like I shouldn't have to make this extra step, but at least it works.