From a table of lines and polylines I am I'm building a seperate table of points (nodes) with their X and Y coordinates stored as attributes. I want the nodes to be unique, so I'm checking to see if a node with the same coordinates has already been inserted by making a feature layer from the nodes table with a SQL clause to selecting any rows with the same coordinates. If the feature layer has zero rows then I insert the new node otherwise I do nothing and move to the next line/polyline.  

The problem I have is that the SQL clause in the Make Feature Layer seems to be selecting rows even where the coordinates do not match. It works fine for the first one but then after that it picks 1 row each time when most or all of the time it should pic zero rows.  

This is making my head hurt. Can any one help please?  

Here is the script..  




    import arcpy
    arcpy.env.overwriteOutput = True
    
    fc_Nodes = 'C:\Users\Rob&LP\Documents\GIS General\DRN Configuration\DRN Sample\LinkNodes_point.shp'
    
    arcpy.DeleteRows_management(fc_Nodes)
    
    fc_Links = 'C:\Users\Rob&LP\Documents\GIS General\DRN Configuration\DRN Sample\DRN_SevUp_14Recs_polyline.shp'
    
    shapeName = arcpy.Describe(fc_Links).shapeFieldName
    
    rows = arcpy.SearchCursor(fc_Links)
    InCurs = arcpy.InsertCursor(fc_Nodes)
    
    Ins = 0
    
    for row in rows:
    
     feat = row.getValue(shapeName)
     ANode = feat.firstPoint
    
    
    #check to see if node has already been inserted
     arcpy.MakeFeatureLayer_management(fc_Nodes, "fl_P1", """"X" = ANode.X""")
     if int(arcpy.GetCount_management("fl_P1").getOutput(0)) == 0:
    
      Ins = Ins + 1
    
      print "NumRows: " + str(arcpy.GetCount_management("fl_P1").getOutput(0))
      print "Inserted: "+ str(Ins)
      print "ANodeX: " + str(ANode.X)
      print ""
    
    
      newNode = InCurs.newRow()
      newNode.SHAPE = ANode
      newNode.setValue("CHECK", 1)
      newNode.setValue("X", ANode.X)
      newNode.setValue("Y", ANode.Y)
      newNode.setValue("ID", Ins)
    
      InCurs.insertRow(newNode)
      del ANode
      arcpy.Delete_management("fl_P1") 
     else:
      
      print "NumRows: " + str(arcpy.GetCount_management("fl_P1").getOutput(0))
      print "NOT Inserted : " + str(ANode.X)
      print ""
      del ANode
      arcpy.Delete_management("fl_P1") 
     
    arcpy.Delete_management("fl_P1")      
    del InCurs
    del rows
    
    
    print "--------------End---------"

`