arcgis python 数据更新

import arcgisscripting
gp = arcgisscripting.create()

# Create update cursor for feature class
rows = gp.UpdateCursor("D:/St_Johns/data.mdb/roads")
row = rows.Next()

# Update the field used in buffer so the distance is based on the road
# type. Road type is either 1, 2, 3 or 4. Distance is in meters.

while row:
    row.buffer_distance = row.road_type * 100
    rows.UpdateRow(row)
    row = rows.Next()