Join in GUI not the same as ArcPy join

Question

I'm trying to join up some data so I can make some rasters. I am doing this in Python but when I create the join in Python in results in an empty attribute table for my shapefile. The columns from both the shapefile and the view I am using in the join are in the shapefile after the join and my view shows up as a joined table in Joins and Relates but there are no data at all.

My Python is:

arcpy.AddJoin_management("Area1_wellspiezometers", "LocId_Calc", "_107062_1_1999", "LocationName")

Where

• Area1_wellspiezometers is a shapefile
• LocId_Calc is an field in Area1_wellspiezometers
• _107062_1_1999 is a view created with arcpy.MakeTableView_management from a table in an MDB.
• LocationName is a field in _107062_1_1999

Alternatively when I do this through the GUI I right click on Area1_wellspiezometers > Joins and Relates > Join... and enter my info as such:

This makes the join as expected and everything is dandy.

What is the difference between these two methods and how can I make the Python do what the GUI is doing?

Answer 1

I needed to save my Table View to disk in order for it to be usable by a join. CopyRows_management was the missing link.

arcpy.MakeTableView_management(outGdb + "\myTable", viewName, sqlFilterForView ,outGdb)
arcpy.CopyRows_management(viewName, saveViewPath)
arcpy.AddJoin_management( shapeLayer  , joinField,  savedViewName  , joinField,"KEEP_COMMON")

Other suggestions like making my view a spatial layer by using arcpy.MakeXYEventLayer_management were not successful.

Answer 2

not sure why it would work in the GUI - but according to the docs under 'Reasons joining tables may fail' - it does list "avoid starting field names with a number or an underscore" - and has similar warnings against the feature name as well.