[GIS] Deleting Feature Class from Geodatabase using list in ArcPy

arcpyfeature-classfile-geodatabase

I am trying to delete several feature classes from a file geodatabase using values stored in a user defined list.

The script runs without error but it does not delete the feature classes.

Any suggestions to what I am doing wrong (using ArcMap 10.3)?

import arcpy

arcpy.env.workspace = r"C:\Data\Temp.gdb"

fc_Delete = ["fcOut1a","fc_Out2a","fc_Out3a"]

for fc in fc_Delete:
    if arcpy.Exists(fc):
        arcpy.Delete_management(fc,"")

Best Answer

Your code is correct, however I would remove the empty string part of the arcpy delete function.

ie:

arcpy.Delete_management(fc)

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[GIS] Deleting feature class features faster using ArcPy

Which part of the script is actually taking up most of the time? There are about 5 other steps going on before you actually start deleting stuff.

You might want to break your script down into bite-sized tests. For example, instead of creating a temporary connection file, listing a bunch of datasets, listing their contents, counting their records, and then finally actually doing what you want to do (deleting features), just pass in a single feature class with a premade connection file to DeleteFeatures and see how long that takes.

If that performs acceptably then create another test to time the next potential trouble spot: counting rows. And another for listing feature classes within a feature dataset, and yet another for listing feature datasets within a geodatabase.

If, on the other hand, DeleteFeatures does not perform acceptably, then at least we know where the problem is. In that case I would be more inclined to look at how your geodatabase is designed:

Are any of your feature datasets versioned? When using versioning there exists an additional pair of A (adds) and D (deletes) tables for each versioned table, and when you delete features you aren't deleting records in the base table, you are adding records to the D table. This will take much longer than if it was not versioned.
Since your feature classes all seem to be in feature datasets, do they participate in geodatabase behavior such as a topology or geometric network? When you add/remove/modify features participating in geodatabase behavior there is a lot more overhead.
Also note that contrary to popular belief, feature datasets are not designed to be used as an organizational tool:

Feature data sets exist in the geodatabase to define a scope for a spatial reference. All feature classes that participate in topological relationships with one another (e.g., a geometric network) must have the same spatial reference. Feature data sets are a way to group feature classes with the same spatial reference so that they can participate in topological relationships with each other.

To most users, feature data sets also have a natural organizational quality, much like a folder on a file system. Since for many GIS applications the majority of the data has the same spatial reference, the temptation to group large numbers of feature classes into feature data sets is irresistible.

Feature data sets, however, are not free. When you open a feature class contained in a feature data set to look at its properties or draw or query it in ArcCatalog™, ArcMap™, or a custom application, all of the other feature classes in that feature data set are also opened. This is done because updates to a feature class in a feature data set can potentially ripple to other feature classes in the feature data set that participate in topological relationships.

From: Multiuser Geographic Information Systems with ArcInfo 8 (April 2000)

So that might be another source of overhead even if they do not participate in a topology or geometric network.

Beyond the arcpy DeleteFeatures/DeleteRows commands:

If you have SDE administration command access you could use:

sdetable -o truncate -t <tablename>

This issues truncate table commands to your DBMS so it should be much faster, but note that this ignores geodatabase behavior.
Using ArcSDESQLExecute to issue TRUNCATE TABLE commands directly (again bypassing geodatabase behavior), but this is very trouble-prone as you would need to issue one for each table that makes up a feature class (base, F, S, I, A, D, etc.) Failing to do this carefully and correctly could leave your data in an inconsistent state.

[GIS] Editing feature class using ArcObjects

I recommend starting and finishing all edits within an edit operation inside of a try block, where a catch block would call AbortOperation.

Something I've always wondered about is whether it makes sense before starting an edit operation to check to see if there's already an operation underway, via IWorkspaceEdit2.IsInEditOperation.

Best Answer

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[GIS] Deleting feature class features faster using ArcPy

[GIS] Editing feature class using ArcObjects

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