Indexing of LandView ® Databases
The LandView datasets, particularly at the National level, contain many data records, and each data file can contain many fields. Only key fields in each file are pre-indexed so as to provide for rapid searching of the databases. Indexing adds content to a LandView file, and, as it is not known which of many fields would be of greatest interest to a researcher, no attempt to index was made beyond key fields.
Locked LandView files, those with the 'Read-only' property set, cannot be indexed. The primary method for viewing and exploring LandView data is to access the data directly from the distribution CD/DVD. These files are locked and cannot be indexed. There are alternate procedures for installing LandView files on an addressable drive, see Alternate LandView Installations, and, while it is not recommended as a normal operating procedure, such files can be unlocked and indexed.
A search of an un-indexed field in LandView, referred to as a Find, can be lengthy. Typically, such search would display a message, as below, as the search continues:
Each LandView database has its Index attribute set to: Automatically turn indexing on if needed. In the first time search of a new data field in an unlocked LandView file, the following message would appear:
Subsequent searches of the same field in the same file would be almost instantaneous.
Working routinely with an unlocked LandView file can lead inadvertently to overwriting of data and the introduction of error. As an indexing procedure, files can be unlocked, but they should be relocked upon completion of the indexing procedure.
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Source: U.S. Census Bureau
Last Revised: Thursday, 26-Jan-2012 15:38:32 EST