Editing Field (computer science) (section)

== File fields ==
[[File:Data Hierarchy diagram showing Employee database example by JeffTan.gif|thumb|File Data Hierarchy diagram]]
Fields may be stored in a [[random access]] [[computer file|file]].<ref name="cpl_p169_quote2">{{cite book
  | last1 = Wilson
  | first1 = Leslie B.
  | last2 = Clark
  | first2 = Robert G.
  | title = Comparative Programming Languages, Third Edition
  | publisher = Addison-Wesley
  | year = 2001
  | page = 169
  | quote = The original use of records was in languages like COBOL, where they were used to define the structure of records held in a file.
  | isbn = 0-201-71012-9
}}</ref> A file may be written to or read from in an arbitrary order. To accomplish the arbitrary access, the [[operating system]] provides a method to quickly ''seek'' around the file.<ref name="upe_p207_quote">{{cite book
  | last1 = Kernighan
  | first1 = Brian W.
  | last2 = Pike
  | first2 = Rob
  | title = The UNIX Programming Environment
  | publisher = Prentice Hall
  | year = 1984
  | page = 207
  | quote = The system call lseek provides a way to move around in a file without actually reading or writing.
  | isbn = 0-13-937699-2
}}</ref> Once the [[Disk read-and-write head|disk head]] is positioned at the beginning of a record, each file field can be read into its corresponding memory field.

File fields are the main storage structure in the [[ISAM|Indexed Sequential Access Method]] (ISAM). In [[relational database]] [[Database theory|theory]], the term ''field'' has been replaced with the terms ''column'' and ''attribute''.<ref name="did_p5_quote">{{cite book
  | last = Date
  | first = C.J.
  | title = Database in Depth
  | publisher = O'Reilly Media, Inc.
  | year = 2005
  | page = 5
  | quote = An n-ary relation can be pictured as a table with n columns; the columns in the picture correspond to attributes of the relation and the rows correspond to tuples.
  | isbn = 0-596-10012-4
}}</ref>