topic Create a Definition Query in Standalone Arcpy/Python Script in Python Questions

Create a Definition Query in Standalone Arcpy/Python Script

JoeBorgione — Wed, 18 Aug 2021 22:11:31 GMT

Been doing some searching here and with the online help; I don't know if this is possible or not:

Create a feature layer and apply a definition query to that feature layer. Then use the feature layer to clip another feature class. I can always make a selection to the feature layer and use the it to clip the feature class, but I'm just wondering....

Re: Create a Definition Query in Standalone Arcpy/Python Script

nzjs — Wed, 18 Aug 2021 22:36:06 GMT

Yes this is possible by accessing the CIM definition for the feature layer. You can read more about that here. https://pro.arcgis.com/en/pro-app/latest/arcpy/mapping/python-cim-access.htm

As for an example, this is roughly what you need to update a layer's definition query, then run your clip afterwards.

def set_definition_query(map_name, layer_name, definition_query): aprx = arcpy.mp.ArcGISProject("CURRENT") for map in aprx.listMaps(map_name): for layer in map.listLayers(): if layer.name == layer_name: cim = layer.getDefinition('V2') # You may not need to update definitionFilterChoices cim.featureTable.definitionFilterChoices[0].definitionExpression = definition_query cim.featureTable.definitionExpression = definition_query layer.setDefinition(cim) # Sample data map_name = 'Map' lyr_name = 'MyLayer' oid = 200 definition = f"OBJECTID = '{oid}'" set_definition_query(map_name, lyr_name, definition)

Re: Create a Definition Query in Standalone Arcpy/Python Script

JoeBorgione — Wed, 18 Aug 2021 22:47:13 GMT

Thanks @nzjs . I should have clarified that I don't have an aprx; I'm just going straight to the data source. I'll see if I can adapt your code to my specific application.

Re: Create a Definition Query in Standalone Arcpy/Python Script

nzjs — Wed, 18 Aug 2021 22:50:26 GMT

I see - in your case you probably do want to use Select by Attribute arcpy tool as mentioned in your post. I'm fairly certain that using and modifying the CIM is more a case of needing to adjust symbology, definition query, popups, etc within an ArcGIS Pro project/maps.

Re: Create a Definition Query in Standalone Arcpy/Python Script

JoshuaBixby — Wed, 18 Aug 2021 22:56:24 GMT

Layer's have a definitionQuery property, just set or update it after creating the layer: Layer—ArcGIS Pro | Documentation

>>> import arcpy >>> >>> fc = # path to feature class >>> fl = arcpy.management.MakeFeatureLayer(fc)[0] >>> fl <arcpy._mp.Layer object at 0x000001E44F9BB388> >>> fl.definitionQuery '' >>> arcpy.management.GetCount(fl) <Result '5'> >>> fl.definitionQuery = "OBJECTID < 3" >>> arcpy.management.GetCount(fl) <Result '2'> >>>

Re: Create a Definition Query in Standalone Arcpy/Python Script

Luke_Pinner — Thu, 19 Aug 2021 06:45:19 GMT

Include a where clause in arcpy.management.MakeFeatureLayer (see the "Expression" parameter)

Re: Create a Definition Query in Standalone Arcpy/Python Script

JoeBorgione — Thu, 19 Aug 2021 12:21:28 GMT

@Luke_Pinner Perfect. Why didn’t I think of that?!

Re: Create a Definition Query in Standalone Arcpy/Python Script

dbKlingdom — Wed, 17 Aug 2022 14:54:29 GMT

Hello, This took a lot longer than I think it should have to code up and test, so we wanted to share. We find replace string/s. This runs in or out of Pro.

#project = arcpy.GetParameterAsText(0)
#old_asset_name = arcpy.GetParameterAsText(1)
#new_asset_name = arcpy.GetParameterAsText(2)

old_asset_name = "Template"
new_asset_name = "AssetName"

project = (r'Your.aprx')
aprx = arcpy.mp.ArcGISProject(project)

m = aprx.listMaps()[0]

# List of Layers in TOC
for lyr in m.listLayers():
arcpy.AddMessage(str(lyr))
arcpy.AddMessage("\n")

## Layer Validation
if lyr.supports("DEFINITIONQUERY"):

# Lists Definition Queries
query = lyr.listDefinitionQueries()
arcpy.AddMessage("Old DQ " + str(query))

## List Dictionary
for dic in query:
# Open dictionary item
for key, value in dic.items():
if key == 'sql':
## print("")
## print(value)
## Find Replace
replace = value.replace(old_asset_name, new_asset_name)

## print("")
## print("SQL " + str(replace))

## Update DIctionary
dic[key] = replace

## print("")
## print("New Query " + str(query))

## update Definition Queries
lyr.updateDefinitionQueries(query)

new_query = lyr.listDefinitionQueries()
arcpy.AddMessage("New DQ " + str(new_query))
arcpy.AddMessage("")

aprx.saveACopy(project)

Re: Create a Definition Query in Standalone Arcpy/Python Script

cweirpatrickco — Thu, 30 May 2024 23:27:53 GMT

Adjusted this slightly but now I can edit a single DQ through arcpy... before everytime I altered the query from arcpy it created a whole new DQ, so I was ending up with a whole list of DQ's.

You saved me a headache, cheers! 🍻