If you create an index using a filter, Analyzer displays “Filtered Index” in the status bar to let you know you are only referencing the part of the file that matches the filter’s condition. A conditional index eliminates records that do not meet a specified condition. This allows you to create separate index files for subsets of a larger file for later manipulation. Do not include a condition if you want the entire file to be indexed.
In addition to an If test, you can specify While, Next and First parameters. Only records from the open table which meet the specified condition will have pointers in the resulting index file. If processing is terminated early by one of these parameters, the subsequent records are not included in the index file and cannot be accessed when using it. Since it may not always be obvious that you are not working with the entire file, to verify that you are working with a filtered index, look for the words “Filtered Index” on the status bar. Only records that meet the index conditions are processed.