Create Domain (Data Management)


Creates an attribute domain in the specified workspace.


  • Domain management involves the following steps:

    1. Create the domain using the this tool.
    2. Add values to or set the range of values for the domain using the Add Coded Value to Domain tool or Set Value For Range Domain tool.
    3. Associate the domain with a feature class using the Assign Domain To Field tool.
  • Coded value domains support only default value and duplicate split policies and default value merge policies.

  • Range domains support all split and merge policies. After a split or merge operation, the attribute values of output features are calculated based on the numeric values of the input features and the specified split or merge policy.


CreateDomain(in_workspace, domain_name, {domain_description}, {field_type}, {domain_type}, {split_policy}, {merge_policy})
ParameterExplanationData Type

The geodatabase that will contain the new domain.


The name of the domain that will be created.


The description of the domain that will be created.


The type of attribute domain to create. Attribute domains are rules that describe the legal values of a field type. Specify a field type that matches the data type of the field to which the attribute domain will be assigned.

  • TEXTAny string of characters.
  • FLOAT Fractional numbers between -3.4E38 and 1.2E38.
  • DOUBLE Fractional numbers between -2.2E308 and 1.8E308.
  • SHORT Whole numbers between -32,768 and 32,767.
  • LONG Whole numbers between -2,147,483,648 and 2,147,483,647.
  • DATEDate and/or time.

The domain type to create:

  • CODEDSpecifies a valid set of values for an attribute. For example, a coded value domain might specify valid pipe material values: CL—cast iron pipe, DL—ductile iron pipe, or ACP—asbestos concrete pipe. This is the default value.
  • RANGESpecifies a valid range of values for a numeric attribute. For example, if distribution water mains have a pressure between 50 and 75 psi, then a range domain would specify these minimum and maximum values.

The split policy of the created domain. The behavior of an attribute's values when a feature that is split is controlled by its split policy.

  • DEFAULTThe attributes of the two resulting features take on the default value of the attribute of the given feature class or subtype.
  • DUPLICATEThe attribute of the two resulting features takes on a copy of the original object's attribute value.
  • GEOMETRY_RATIOThe attributes of resulting features are a ratio of the original feature's value. The ratio is based on the proportion into which the original geometry is divided. If the geometry is divided equally, each new feature's attribute gets one-half the value of the original object's attribute. The geometry ratio policy only applies to range domains.

The merge policy of the created domain. When two features are merged into a single feature, merge policies control attribute values in the new feature.

  • DEFAULTThe attribute of the resulting feature takes on the default value of the attribute of the given feature class or subtype. This is the only merge policy that applies to nonnumeric fields and coded value domains.
  • SUM_VALUESThe attribute of the resulting feature takes on the sum of the values from the original feature's attribute. The sum values policy only applies to range domains.
  • AREA_WEIGHTEDThe attribute of the resulting feature is the weighted average of the attribute values of the original features. This average is based on the original feature's geometry. The area weighted policy only applies to range domains.

Derived Output

NameExplanationData Type

The updated input workspace.


Code sample

CreateDomain example 1 (Python window)

The following Python window script demonstrates how to use the CreateDomain function in immediate mode.

import arcpy
arcpy.env.workspace = "C:/data"
arcpy.CreateDomain_management("montgomery.gdb", "Materials", 
                              "Valid pipe materials", "TEXT", "CODED")
CreateDomain example 2 (stand-alone script)

This stand-alone script utilized the CreateDomain function as part of a workflow to create an attribute domain, assign values to it, and assign the domain to a field in a feature class.

# Name:
# Description: Create an attribute domain to constrain pipe material values
# Import system modules
import arcpy
# Set the workspace (to avoid having to type in the full path to the data 
# every time)
arcpy.env.workspace = "C:/data"
# Set local parameters
domName = "Material4"
gdb = "montgomery.gdb"
inFeatures = "Montgomery.gdb/Water/Distribmains"
inField = "Material"

# Process: Create the coded value domain
arcpy.CreateDomain_management("montgomery.gdb", domName, "Valid pipe materials", 
                              "TEXT", "CODED")

# Store all the domain values in a dictionary with the domain code as the "key" 
# and the domain description as the "value" (domDict[code])
domDict = {"CI":"Cast iron", "DI": "Ductile iron", "PVC": "PVC", 
           "ACP": "Asbestos concrete", "COP": "Copper"}
# Process: Add valid material types to the domain
# use a for loop to cycle through all the domain codes in the dictionary
for code in domDict:        
    arcpy.AddCodedValueToDomain_management(gdb, domName, code, domDict[code])
# Process: Constrain the material value of distribution mains
arcpy.AssignDomainToField_management(inFeatures, inField, domName)

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes

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