Ferret File System/v0.1/SQL/firev: Difference between revisions

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==About==
==About==
"{{l/fileferret|terms/firev|Firev}}" is short for "file revision". A firev is a particular series of byte values that represents a particular revision, or version, of a {{l/fileferret|terms/fideal|fideal}}. Fideal records are generally only created when multiple copies of the same file are found, though they may also be created manually in order to track more information about a file.
* '''Purpose''': tracks revisions to {{l/same|file}}s (see {{l/fileferret|terms/firev}})
 
* '''Future''':
A firev can be created either deliberately (as a result of user editing) or accidentally (imperfect transcription, drive corruption, viral infection).
** We may want to support multiple types of hash, in which case there would be a separate firev_hash table containing the output of each hash-type for each firev hashed.
 
** not sure if we should be tracking FirstFound and LastFound here. I expect them to be useful, but they might be better determined by looking at the event records.
* '''Future''': not sure if we should be tracking FirstFound and LastFound here. Though they will probably be useful, they might be better determined by looking at the event records.
===Fields===
===Fields===
* '''isDelib''': TRUE if this is known to be a deliberate user edit of the parent firev (must be FALSE if isAccid is TRUE)
* '''isDelib''': TRUE if this is known to be a deliberate user edit of the parent firev (must be FALSE if isAccid is TRUE)

Revision as of 23:31, 27 February 2016

About

  • Purpose: tracks revisions to files (see terms/firev)
  • Future:
    • We may want to support multiple types of hash, in which case there would be a separate firev_hash table containing the output of each hash-type for each firev hashed.
    • not sure if we should be tracking FirstFound and LastFound here. I expect them to be useful, but they might be better determined by looking at the event records.

Fields

  • isDelib: TRUE if this is known to be a deliberate user edit of the parent firev (must be FALSE if isAccid is TRUE)
  • isAccid: TRUE if this is known to be an accidental corruption of the parent firev (must be FALSE if isDelib is TRUE)
  • Descr should describe, if known, what distinguishes this firev from other firevs of the same fideal (or from the parent firev, if there is one).
  • FileHash is a unique fingerprint (hash) of the file, using an algorithm unlikely to produce duplicate hashes for even the smallest variation. See hash() for details; apparently these can be as long as 128 hexadecimal digits = 64 bytes.

I think we're also going to want a field, possibly called FileMean, which changes very little (or not at all) when there are small changes to the data. This should make it easier to connect firevs to a fideal.

Rules

  • isDelib and isAccid can both be FALSE if the cause of the firev is not known (i.e. we know there's a new firev, but not whether it was deliberate or accidental), but they cannot both be TRUE.

History

  • 2012-12-25 Adapted/created from fideals
  • 2016-02-27
    • Added FirstFound, LastFound timestamps.
    • Scrapped Fideal, Parent.
    • Renamed "firevs" -> "firev".

SQL

<mysql>CREATE TABLE `firev` ( 

 `ID`        INT  NOT     NULL AUTO_INCREMENT,
 `isDelib`   BOOL DEFAULT FALSE COMMENT "TRUE = this is known to be a deliberate user edit of the parent",
 `isAccid`   BOOL DEFAULT FALSE COMMENT "TRUE = this is known to be an accidental corruption of the parent",
 `Descr`     VARCHAR(255)       COMMENT "description of differences",
 `FileSize`  INT                COMMENT "correct file size in bytes",
 `FileHash`  VARBINARY(64)      COMMENT "unique hash",
 `FirstFound`  DATETIME     NOT NULL COMMENT "time/date when file was first found during a scan",
 `LastFound`   DATETIME     NOT NULL COMMENT "time/date when file was most recently found during a scan",
 PRIMARY KEY(`ID`)

) ENGINE = MYISAM;</mysql>

scrapped

These might get used later, but I suspect they don't belong here: <mysql> 

 `ID_Fideal` INT  DEFAULT NULL  COMMENT "ID of ideal file",
 `ID_Parent` INT  DEFAULT NULL  COMMENT "ID of parent firev, if any",

</mysql>

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