Index Item (Coverage)
Summary
Creates an attribute index to increase access speed to the specified item during query operations.
Usage
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Indexed items speed up selection operations of large INFO files.
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Item indexes are preserved when the coverage or INFO table is copied to a new location.
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Item indexes are preserved when exporting and importing a coverage to an interchange (.e00) file using the Export To Interchange File and Import From Interchange File tools.
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Items must be indexed to support native mode reselects against external database management system (DBMS) tables.
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An index file becomes outdated if the following commands are used on the INFO table: Calculate Field, Update, Build, or Clean. Attempting to use the outdated index will cause the following message to be generated: "Index file is obsolete." If you receive this message, rebuild the index file and continue.
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The following commands are affected by indexed items: Eliminate, Select, and Join Info Tables.
Syntax
| Parameter | Explanation | Data Type |
in_info_table |
The name of the INFO table containing the item to be indexed | INFO Table |
index_item |
The name of the item to be indexed | INFO Item |
Code Sample
The following stand-alone script demonstrates how to index an item in a coverage, and then select features using the indexed item.
# Name: IndexItem_Example.py
# Description: Indexes an item then uses that item to select features.
# Requirements: ArcInfo Workstation
# Import system modules
import arcpy
from arcpy import env
# Set environment settings
env.workspace = "C:/data"
# Set local variables
inInfoTable = "stream/arc"
indexItem = "STRM_ORD"
inCover = "stream"
outCover = "C:/output/lowerstreams"
infoExpress = ["RESELECT STRM_ORD > 3"]
# Execute IndexItem
arcpy.IndexItem_arc(inInfoTable, indexItem)
arcpy.Reselect_arc(inCover, outCover, infoExpress)