What are the purpose for having variable length records? What kinds of separator characters are required for each?
Variable-Length Records - Variable-length records are those records that are of various sizes. A file may holds variable-length records in any of the subsequent situations:
• Records having variable length fields - In this case, the end-of-field symbol along with end-of-record symbol could be used as the separator characters.
• Records having repeating fields - In this case, the number of repetitions of repeating area can be used along with end-of-record symbol as the separator characters.
• Records having optional fields - In this case, the end-of-field symbol along with end-of-record symbol could be used as the separator characters.
• File containing records of various record types - In this case, a special field (or control field) can be prefixed with every record and end-of-record symbol could be used as the separator characters.
In each of the above situations either we can use end-of-record symbol or the length of every record can be prefixed at the starting of the record for the separation of the variable-length records.