What are the reasons for having variable length records? What are the various ways to store variable length records?

Variable-length records arise in a database in various ways:

(i)Storage of multiple items in a file.
(ii)Record types allowing variable field size
(iii)Record types allowing repeating fields
Various ways of storing variable length records:

(i) In fixed form through allocating every record, maximum amount of space in which can be occupied a record and padding smaller sized records along with nulls.
(ii) Special separator characters among the records to delineate variable length records.