parameter contents too long in python geoprocessing command

GeorgieCassar

I have a script that uses the arcpy.MakeQueryTable_management command to join a spatial with a non-spatial table.

It works fine until I add lots and lots more fields into the variable that lists all the fields I want to include.  Once it exceeds 255 characters in length, it error's......Understandably as a string can only hold so much.

ie:  In the command   arcpy.MakeQueryTable_management(tableList, lyrName,"ADD_VIRTUAL_KEY_FIELD", keyField, fieldList, whereClause)

The fieldList variable contains the many fields.

Works when fieldlist looks like this

fieldList = ['Cadastre_Joiner.shape', 'paetbl_CoolingTowers.ApplicationNo', 'paetbl_CoolingTowers.PropAddress']

but breaks when I add lots more field names to this variable exceeding 255 characters.

Does anyone know a better way I can make this work using different processes or methods to enter the field name values ?

JoshuaBixby

What exactly is your error message?  I agree with Dan Patterson​ that the "exceeding 255 characters" error seems odd in this situation.

Are you using an enterprise database?  If so, have you thought about using a Query Layer instead?

The Make Query Table documentation is, interesting let's say.  The syntax table for the tool shows the in_field parameter with a list format, but the Data Type is listed as Value Table.  The example provided reinforces the notion of using a list, but I believe the Data Type part is more accurate in that a Value Table is what is likely being processed by the tool.  The tool seems to accept a Python list and converts it into a Value Table, but there appears to be limits to that convenience.

Instead of creating a really long list, I would try creating and populating a Value Table and then pass that into the tool.