Labeling related tables using ArcPy?

Question

I want to lable feature class with related table.One of the solution for this goal is writing script in the Expression of label tab ( How To: Label a related table). But i don't want to scripting in Expression.Then it's not as simple as the Esri solution.

My code is working properly but i could not iterate "lblclass.expression" for the row1 and the related table ( row1) is not iterate and just show one value for all labels.How to iterate related table value for labeling ?

import arcpy
table = "table"
listtlabel = []
mxd = arcpy.mapping.MapDocument("CURRENT")
layer = arcpy.mapping.ListLayers(mxd, "Point")[0]
fielddelimi1 = arcpy.AddFieldDelimiters(table, "Code")
sql_exp1 = "{0} = {1}".format(fielddelimi1,309)

if layer.supports("LABELCLASSES"):
    for lblclass in layer.labelClasses:
        with arcpy.da.SearchCursor(table,["Code1","Row"],sql_exp1) as cur1:
                for row1 in cur1:
                    listtlabel.append(row1[0])

                lblclass.expression = '[Code]' + '&'+ str(row1[1])
                str1=','.join(str(e) for e in listtlabel)
                print str1
                with arcpy.da.SearchCursor(layer,"Code2") as cur:
                    for row in cur:
                        if row[0] in listtlabel:
                             lblclass.SQLQuery = '"Code2"' + "IN" + "({0})".format(str1)
lblclass.showClassLabels = True
layer.showLabels = True
arcpy.RefreshActiveView()
del mxd

Answer 1

Labeling a layer with the values of stand-alone table (that is associated to the layer with 1-Many relationship). See my accepted answer for this post plus my first response that has links to discussions of the source code.

I will say it again. NEVER use embedded cursors for relating two tables. That is the most inefficient, horribly performing, and memory intensive approach you can take. You need random access to perform relates, which embedded cursors do not support. Dictionaries support random access and solve the problem very elegantly.