topic Re: Creating a geodatabase and setting it to env.workspace in Python Questions

Creating a geodatabase and setting it to env.workspace

EricEagle — Sat, 11 Dec 2021 18:06:24 GMT

Any reason why this wouldn't be working?

import arcpy
import os

basedir = 'C:\\Temp'
gdb_name = 'TestGDB'
gdb = os.path.join(basedir, gdb_name)

if arcpy.Exists(gdb):
    arcpy.env.workspace = gdb
else:
    gdb = arcpy.CreateFileGDB_management(basedir, gdb_name)
    arcpy.env.workspace = gdb‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I must not be understanding how .Exists() resolves, for if the gdb already exists, it gives me:

arcgisscripting.ExecuteError: ERROR 000258: Output C:\Temp\TestGDB.gdb already exists

Failed to execute (CreateFileGDB)

If the gdb does not exist, it gives me:

RuntimeError: Object: Error in accessing environment <workspace>

Re: Creating a geodatabase and setting it to env.workspace

JoshuaBixby — Thu, 23 Mar 2017 14:03:57 GMT

When creating the file geodatabase path for setting a workspace, you need to include the ".gdb" on the end, otherwise you are setting the workspace to a folder.

Re: Creating a geodatabase and setting it to env.workspace

IanMurray — Thu, 23 Mar 2017 14:04:52 GMT

You are missing the file extension in your gdb variable. gdb_name needs the extension on it before you join the path.

Re: Creating a geodatabase and setting it to env.workspace

EricEagle — Thu, 23 Mar 2017 14:12:01 GMT

Thanks Ian/Joshua,

When I include the .gdb extension (gdb_name = 'TestGDB.gdb') and the geodatabase exists, it completes. When the geodatabase does not exist, it creates the TestGDB.gdb object, but still gives me the same runtime error.

Re: Creating a geodatabase and setting it to env.workspace

IanMurray — Thu, 23 Mar 2017 14:23:15 GMT

Can you check to make sure it creates the GDB? I think its not creating it at all.

Make line 11 just:

arcpy.CreateFileGDB_management(basedir, gdb_name)

Right now instead of creating the actual gdb, you are setting a variable equal to it, which I'm not sure what that would do but it likely isn't creating it.

Re: Creating a geodatabase and setting it to env.workspace

EricEagle — Thu, 23 Mar 2017 14:27:59 GMT

Thanks Ian. It felt like I should be able to dump the method into a variable in one step like other methods to save a line of code, but regardless, it works now, thank you.

Re: Creating a geodatabase and setting it to env.workspace

IanMurray — Thu, 23 Mar 2017 14:56:15 GMT

Hm it does create the GDB when you set it equal to a variable. I guess the issue with your script is the fact that arcpy.env.workspace is looking for a workspace as an input, whereas you were setting it equal to geoprocessing operation that creates the workspace.

Re: Creating a geodatabase and setting it to env.workspace

JonathanQuinn — Thu, 23 Mar 2017 19:04:04 GMT

Just to provide more insight, if you print the gdb variable, you'll get "<basedir>\<gdb_name>". The OS separator between the out file path and FGDB name isn't escaped properly, as it's set to a backslash, which is why you see that runtime error when trying to use the gdb variable as is. In one line, this worked:

gdb = str(arcpy.CreateFileGDB_management(outDir,outName)).replace("\\","/")

You can replace the single backslash, (escaped with a double backslash), with a forward slash.

Re: Creating a geodatabase and setting it to env.workspace

JoshuaBixby — Sat, 11 Dec 2021 18:06:26 GMT

I am using ArcGIS 10.5, and Create File GDB returns properly escaped results:

>>> var = arcpy.CreateFileGDB_management(r'C:\tmp','test')
>>> var
<Result 'C:\\tmp\\test.gdb'>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍
>>> arcpy.Exists(var)
True
>>> ‍‍‍‍‍‍

The double backslashes are perfectly valid, they don't have to be forward slashes.

Re: Creating a geodatabase and setting it to env.workspace

JonathanQuinn — Sat, 11 Dec 2021 18:06:29 GMT

If you call on the variable without printing, it'll be correct as a Result object. If you print the variable you'll see the backslash is not escaped:

>>> gdb = arcpy.CreateFileGDB_management("C:/Temp","blah.gdb")
>>> gdb
<Result 'C:/Temp\\blah.gdb'>
>>> print(gdb)
C:/Temp\blah.gdb
>>> arcpy.Exists(gdb)
True
>>> arcpy.env.workspace = gdb
Runtime error 
Traceback (most recent call last):
 File "<string>", line 1, in <module>
 File "c:\program files (x86)\arcgis\desktop10.5\arcpy\arcpy\geoprocessing\_base.py", line 541, in set_
 self[env] = val
 File "c:\program files (x86)\arcgis\desktop10.5\arcpy\arcpy\geoprocessing\_base.py", line 601, in __setitem__
 ret_ = setattr(self._gp, item, value)
RuntimeError: Object: Error in accessing environment <workspace>
>>> arcpy.env.workspace = str(gdb).replace("\\","/")
>>> arcpy.env.workspace
u'C:/Temp/blah.gdb'‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

There seems to be different implementations of arcpy.Exists and arcpy.env.workspace, as the latter seems to look at the result as a string.

Re: Creating a geodatabase and setting it to env.workspace

curtvprice — Sat, 11 Dec 2021 18:06:32 GMT

This is right on.

eric.eagle It's a little confusing that you have named the result object the same as the gdb full path. A better way to implement this is:

r_gdb = arcpy.CreateFileGDB_management(basedir, gdb_name)‍

The result object can be used as input parameter to a tool, in which case it will be converted to a path. Or you can convert it to a path yourself with either of these statements -- or just use gdb which you set earlier in the code.

gdb = r_gdb.getOutput(0)
gdb = str(r_gdb)‍‍

Re: Creating a geodatabase and setting it to env.workspace

JoshuaBixby — Sat, 11 Dec 2021 18:06:34 GMT

This one fascinated me a bit. On one hand, I am surprised I haven't run into the issue before; but on the other hand, I don't work with the GPEnvironment class much, at least not directly.

Since arcpy.env and arcpy.Exists both go through arcpy.geoprocessing._base, it got me wondering why passing a Result object to one works fine but the other one chokes. It turns out, one uses gp_fixargs while the other one doesn't. gp_fixargs is designed to do several things, one of which being extract values from Result objects:

>>> from arcpy.geoprocessing._base import gp_fixargs
>>> res = arcpy.CreateFileGDB_management(r"C:\tmp", "test")
>>> type(res)
<class 'arcpy.arcobjects.arcobjects.Result'>
>>> res
<Result 'C:\\tmp\\test.gdb'>
>>> 
>>> fixed_args = gp_fixargs(res, True)
>>> fixed_args
[u'C:\\tmp\\test.gdb']
>>> fixed_args[0]
u'C:\\tmp\\test.gdb'
>>> 
>>> unicode(res._arc_object)
u'C:\\tmp\\test.gdb'
>>> ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Both arcpy.env and arcpy.Exists check for the presence of an _arc_object property. Whereas arcpy.Exists uses gp_fixargs, arcpy.env simply tries to use the _arc_object value directly instead of passing it to unicode first.

I guess a question for Esri is why doesn't arcpy.env use gp_fixargs? I assume it creates some problem somewhere, but who knows, maybe it is simply an oversight.

Re: Creating a geodatabase and setting it to env.workspace

curtvprice — Sat, 25 Mar 2017 16:33:49 GMT

Thanks for digging that up, Joshua. You know how much I like a little dirt on how they do stuff underneath what's documented!

Maybe it was kind of a design decision, arcpy.env is not a tool, so you should hand it a string or a non-result object.