COBOL Indexed Vs Sort top differences you need to know

Indexed file and sorted file both are different concepts. When I asked in an interview many developers confused about it to tell right answer. These quick ideas help you understand well.

Index Vs Sort
Index vs Sort in COBOL

Indexed file Vs Sorted file

Indexed file

  • Indexed files use a primary key field to identify the records of an original file in a database. A primary key field is a unique field. An indexed file consists of actual records sorted based on the primary key field value
  • An indexed file also consists of alternate keys, which build the alternate index. Unlike primary keys, the alternate keys in an indexed file do not have actual records.
  • The advantage of primary key field values is that because of the indexing of actual records, you require only one input-output operation to access records in an indexed file

Sorted file

  • Sorting is the arrangement of the records of a file in ascending or descending order based on specific key data items
  • For example, you can sort a file containing employee payroll records by employee identification number in ascending order. You can sort a file on more than one data item. Example ID and Department
  • When you sort a sequential file, its records are stored on the hard disk and you can only access them serially. It is not possible to access all the records of a file simultaneously.

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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.