diff options
Diffstat (limited to 'pod/modpods/AnyDBMFile.pod')
| -rw-r--r-- | pod/modpods/AnyDBMFile.pod | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/pod/modpods/AnyDBMFile.pod b/pod/modpods/AnyDBMFile.pod index 7b579ca34c..5692144586 100644 --- a/pod/modpods/AnyDBMFile.pod +++ b/pod/modpods/AnyDBMFile.pod @@ -10,16 +10,23 @@ NDBM_File, ODBM_File, SDBM_File, GDBM_File - various DBM implementations =head1 DESCRIPTION -This module is a "pure virtual base class"--it has nothing of us its own. +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 -L<DB_File>), 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: +L<DB_File>), 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: @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File); -This makes it trivial to copy database formats: +Note, however, that an explicit use overrides the specified order: + + use GDBM_File; + @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File); + +will only find GDBM_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; |