File copying utilities are often used for taking back

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Unformatted text preview: ut parameters, varies from one sorting utility to another. These parameters decide the extent and sophistication of sorting utilities. A sorting utility enables users to sp6cify their particular sequencing requirements by means of simple parameters. The user specifies the sort keys, and also details about the type of file such as storage device, file labels, record structure. The sorting utility reads the unsequenced input file, and by means of various copying techniques ultimately produces an output file, which contains the records of the input file ordered in the required sequence. Searching A file searching utility is used to find a particular record from a file. The searching is carried out with respect to certain specified fields (known as keys) within the record. For example, in the employee file of Figure 16.4, the user can specify the value 202 for the employee code field to request the computer to search the corresponding employee's record. The efficiency of a search algorithm depends on the file organization. For example, to search a particular recon in a sequential file, the file is scanned sequentially beginning with the first record and the specified key i compared oneby-one with the key field of each record. The search process terminates when the record with the matching key is found. On the other hand, direct or index sequential file organizations enable immediate access to the desired record with the help of either the hashing algorithm (in case of direct file organization) or the index file (in case of index sequential file organization). The user needs to only specify the file and the key, and the searching utility searches through the file and produces the desired record. Normally, the time required to search a particular record from a direct or index sequential file is much less as compared to the time required to search it from a sequential file. Merging A file merging utility is used to combine the records of two or more ordered (sorted) files into a si...
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This document was uploaded on 04/07/2014.

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