Ferret File System/v0.1/SQL/firev

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

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 = InnoDB;

scrapped

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

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