Add a definition Query with python

[PeterVersteeg]

I want to add a difinition query with python so far i have this

import arcpy  
  
mxd = arcpy.mapping.MapDocument(r"Y:\TRUTTA\Trutta_new\TruttaMaps\test.mxd")


for lyr in arcpy.mapping.ListLayers(mxd, "*"):
    if lyr.name == "chimney_p":
        lyr.definitionQuery = """"Trutta_Map" = '19A4'"""

In my pythonWin it seems to work BUT the query in my shape did not get the new query.

anyone know why that is ?

[DanPatterson_Retired]

The query may have work, but it isn't going to show up unless you are running the script against "CURRENT" See example 2 in this link  

[PeterVersteeg]

thank you Dan this gives my samething to read in the train and learn more about the mapping.

gr Peter

[OwainCatton · Accepted solution]

Hi Peter,

You are missing just the last step, saving the MXD when you have finished editing the layers.

So your code should read.

import arcpy

mxd = arcpy.mapping.MapDocument(r"Y:\TRUTTA\Trutta_new\TruttaMaps\test.mxd")

for lyr in arcpy.mapping.ListLayers(mxd, "*"):
     if lyr.name == "chimney_p":
          lyr.definitionQuery = """"Trutta_Map" = '19A4'"""

mxd.save()

Hope that helps,

Owain

[PeterVersteeg]

Thank you Owain,

That did the trick. Did not
know about the save part. My fist try was a error because I had the mxd open in
arcmap. In other scripts a had lock errors. Same scripts work even if the mxd
is open. What are the rules for this ? where can I read about it ?

Greetings Peter

[OwainCatton]

Afternoon Peter,

As Dan mentioned above, the use of CURRENT instead of a file path would mean that the Python script will edit the current ArcMap session, where as if you specify the file path the Python script will open a new session, hence the locks errors your were getting as you had the MXD already open.

You can read more here http://resources.arcgis.com/en/help/main/10.2/index.html#//00s30000000r000000

• MapDocument Example 1
  If you have a the MXD open in ArcMap and want to run a script on its contents use CURRENT
• MapDocument Example 2
  If you want to run the script independently you specifiy te full File Path

Owain