What are the different rules for performing SORT operation?

SORT operations are performed when the merging of two or more files is done. It is done for arranging the data in ascending or descending order. The following rules have to be taken care of while conducting SORT operation-

• Input and output files must be closed. Input file is the file that has to be sorted in a particular sequence. The output file is the result that we get after the sorting process. We have to make sure that both these files are closed during the SORTING process.
• A SELECT clause should be present in working files. Work files are used for holding records during the sorting process.
• Input and output files must have FD entries.
• Also, short descriptions should be there in the file section of work files.