Add Join (Data Management)

License Level:BasicStandardAdvanced

Summary

Joins a layer to another layer or table (where layer is a feature layer, table view, or raster layer with a raster attribute table) based on a common field.

The records in the Join Table are matched to the records in the input Layer Name. A match is made when the input join field and output join field values are equal. This join is temporary.

Illustration

Add Join

Usage

Syntax

AddJoin_management (in_layer_or_view, in_field, join_table, join_field, {join_type})
ParameterExplanationData Type
in_layer_or_view

The layer or table view to which the join table will be joined.

Mosaic Layer; Raster Catalog Layer; Raster Layer; Table View
in_field

The field in the input layer or table view on which the join will be based.

Field
join_table

The table or table view to be joined to the input layer or table view.

Mosaic Layer; Raster Catalog Layer; Raster Layer; Table View
join_field

The field in the join table that contains the values on which the join will be based.

Field
join_type
(Optional)

Specifies what will be done with records in the input that match a record in the join table.

  • KEEP_ALLAll records in the input layer or table view will be included in the output—also known as an outer join. This is the default.
  • KEEP_COMMONOnly those records in the input that match to a row in the join table will be present in the result—also known as an inner join.
Boolean

Code Sample

AddJoin example 1 (Python window)

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

import arcpy
from arcpy import env
env.workspace = "C:/data"
arcpy.MakeFeatureLayer_management ( "Habitat_Analysis.gdb/vegtype", "veg_layer")
arcpy.AddJoin_management( "veg_layer", "HOLLAND95", "vegtable.dbf", "HOLLAND95")
arcpy.CopyFeatures_management( "veg_layer", "Habitat_Analysis.gdb/vegjoin")
AddJoin example 2 (stand-alone script)

This stand-alone script shows the AddJoin function as part of a workflow to join a table to a feature class, then extract desired features.

# Name: AttributeSelection.py
# Purpose: Join a table to a featureclass and select the desired attributes

# Import system modules
import arcpy
from arcpy import env

try:
    # Set environment settings
    env.workspace = "C:/data"
    env.qualifiedFieldNames = False
    
    # Set local variables    
    inFeatures = "Habitat_Analysis.gdb/vegtype"
    layerName = "veg_layer"
    joinTable = "vegtable.dbf"
    joinField = "HOLLAND95"
    expression = "vegtable.HABITAT = 1"
    outFeature = "Habitat_Analysis.gdb/vegjoin"
    
    # Create a feature layer from the vegtype featureclass
    arcpy.MakeFeatureLayer_management (inFeatures,  layerName)
    
    # Join the feature layer to a table
    arcpy.AddJoin_management(layerName, joinField, joinTable, joinField)
    
    # Select desired features from veg_layer
    arcpy.SelectLayerByAttribute_management(layerName, "NEW_SELECTION", expression)
    
    # Copy the layer to a new permanent feature class
    arcpy.CopyFeatures_management(layerName, outFeature)
    
except Exception, e:
    # If an error occurred, print line number and error message
    import traceback, sys
    tb = sys.exc_info()[2]
    print "Line %i" % tb.tb_lineno
    print e.message

Environments

Related Topics

Licensing Information

ArcGIS for Desktop Basic: Yes
ArcGIS for Desktop Standard: Yes
ArcGIS for Desktop Advanced: Yes
11/18/2013