AnyDBMFile(3)                                                  AnyDBMFile(3)



NAME
     AnyDBM_File - provide framework for multiple DBMs

     NDBM_File, DB_File, GDBM_File, SDBM_File, ODBM_File - various DBM
     implementations

SYNOPSIS
         use AnyDBM_File;


DESCRIPTION
     This module is a "pure virtual base class"--it has nothing of its own.
     It's just there to inherit from one of the various DBM packages.  It
     prefers ndbm for compatibility reasons with Perl 4, then Berkeley DB (See
     the DB_File manpage), GDBM, SDBM (which is always there--it comes with
     Perl), and finally ODBM.   This way old programs that used to use NDBM
     via dbmopen() can still do so, but new ones can reorder @ISA:

         BEGIN { @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File) }
         use AnyDBM_File;

     Having multiple DBM implementations makes it trivial to copy database
     formats:

         use POSIX; use NDBM_File; use DB_File;
         tie %newhash,  'DB_File', $new_filename, O_CREAT|O_RDWR;
         tie %oldhash,  'NDBM_File', $old_filename, 1, 0;
         %newhash = %oldhash;


     DBM Comparisons

     Here's a partial table of features the different packages offer:

                              odbm    ndbm    sdbm    gdbm    bsd-db
                              ----    ----    ----    ----    ------
      Linkage comes w/ perl   yes     yes     yes     yes     yes
      Src comes w/ perl       no      no      yes     no      no
      Comes w/ many unix os   yes     yes[0]  no      no      no
      Builds ok on !unix      ?       ?       yes     yes     ?
      Code Size               ?       ?       small   big     big
      Database Size           ?       ?       small   big?    ok[1]
      Speed                   ?       ?       slow    ok      fast
      FTPable                 no      no      yes     yes     yes
      Easy to build          N/A     N/A      yes     yes     ok[2]
      Size limits             1k      4k      1k[3]   none    none
      Byte-order independent  no      no      no      no      yes
      Licensing restrictions  ?       ?       no      yes     no







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AnyDBMFile(3)                                                  AnyDBMFile(3)



     [0] on mixed universe machines, may be in the bsd compat library, which
         is often shunned.

     [1] Can be trimmed if you compile for one access method.

     [2] See the DB_File manpage. Requires symbolic links.

     [3] By default, but can be redefined.

SEE ALSO
     dbm(3), ndbm(3), DB_File(3)












































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