mdw@git.distorted.org.uk Git - disorder/blob - server/README.dbversions

   1 DisOrder Database Versions
   2 ==========================
   3
   4 If no _dbversion global preference is found then database version 1 is
   5 assumed.  Database versions 2 and above always have a _dbversion
   6 global preference.
   7
   8 Old database versions can be PARTIALLY emulated for testing purposes
   9 by setting the undocument dbversion configuration item.  Setting it on
  10 a production system would be a terrible idea.
  11
  12 Database Version 1
  13 ------------------
  14
  15 Path names are in UTF-8, but with no normalization applied: you get
  16 whatever the filesystem gives you.
  17
  18 Search terms are split according to the old words() function.
  19   - "/", ".", "+", "&", ":", "_" and "-" are considered to be separators
  20   - anything in General_Category Cc, Cf, Co, Cs, Zl, Cp, Sz, Pe or Ps
  21     is considered to be a separator
  22   - anything else in General_Category Ll, Lm, Lo, Lt, Lu, Nd, Nl, No,
  23     Sc, Sk, Sm or So is considered to be part of a word
  24   - everything else is ignored
  25
  26 Search terms are case-folded by applying the CaseFolding.txt mapping,
  27 without any attempt at normalization.
  28
  29 Database Version 2
  30 ------------------
  31
  32 Path names are in UTF-8, normalized to NFC.
  33
  34 Search terms are split according to the default Unicode word boundary
  35 detection algorithm.
  36
  37 Search terms are case-folded using the Unicode case-folding algorithm,
  38 normalizing to NFKD.
  39
  40 Things that haven't been done yet:
  41   - undump support for new dbversion
  42   - automatic upgrade from dbversion 1