NAME¶
ORLite::Mirror - Extend ORLite to support remote SQLite databases
SYNOPSIS¶
# Regular ORLite on a readonly SQLite database
use ORLite 'path/mydb.sqlite';
# The equivalent for a remote (optionally compressed) SQLite database
use ORLite::Mirror 'http://myserver/path/mydb.sqlite.gz';
# All available additional options specified
use ORLite::Mirror {
url => 'http://myserver/path/mydb.sqlite.gz',
maxage => 3600,
show_progress => 1,
env_proxy => 1,
prune => 1,
index => [
'table1.column1',
'table1.column2',
],
};
DESCRIPTION¶
ORLite provides a readonly ORM API when it loads a readonly SQLite database from
your local system.
By combining this capability with LWP, ORLite::Mirror goes one step better and
allows you to load a SQLite database from any arbitrary URI in readonly form
as well.
As demonstrated in the synopsis above, you using ORLite::Mirror in the same way,
but provide a URL instead of a file name.
If the URL explicitly ends with a '.gz' or '.bz2' then ORLite::Mirror will
decompress the file before loading it.
OPTIONS¶
ORLite::Mirror adds an extensive set of options to those provided by the
underlying ORLite library.
url¶
The compulsory "url" parameter should be a string containing the
remote location of the SQLite database we will be mirroring.
ORLite::Mirror supports downloading the database compressed, and then
transparently decompressing the file locally. Compression support is
controlled by the extension on the remote database.
The extensions ".gz" (for gunzip) and ".bz2" (for bunzip2)
are currently supported.
maxage¶
The optional "maxage" parameter controls how often
ORLite::Mirror should check the remote server to see if the data has
been updated.
This allows programs using the database to start quickly the majority of the
time, but continue to receive automatic updates periodically.
The value is the number of integer seconds we should avoid checking the remote
server for. The default is 86400 seconds (one 24 hour day).
show_progress¶
The optional "show_progress" parameter will be passed through to the
underlying LWP::UserAgent that will fetch the remote database file.
When set to true, it causes a progress bar to be displayed on the terminal as
the database file is downloaded.
env_proxy¶
The optional "env_proxy" parameter will be passed through to the
underlying LWP::UserAgent that will fetch the remote database file.
When set to true, it causes LWP::UserAgent to read the location of a proxy
server from the environment.
prune¶
The optional "prune" parameter should be used when the surrounding
program wants to avoid leaving files on the host system.
It causes any files or directories created during the operation of
ORLite::Mirror to be deleted on program exit at "END"-time.
index¶
One challenge when distributing SQLite database is the quantity of data store on
disk to support the indexes on your database.
For a moderately indexed database where all primary and foreign key columns have
indexes, the amount of data in the indexes can be nearly as large as the data
stored for the tables themselves.
Because each user of the database module will be interested in different things,
the indexes that the original creator chooses to place on the database may not
even be used at all and other valuable indexes may not exist at all.
To allow sufficiently flexibility, we recommend that SQLite database be
distributed without any indexes. This greatly reduces the file size and
download time for the database file.
The optional "index" parameter should then be used by each different
consumer of that module to index just the columns that are of specific
interest and will be used in the queries that will be run on the database.
The value should be set to an "ARRAY" reference containing a list of
column names in "tablename.columnname" form.
index => [
'table1.column1',
'table1.column2',
],
SUPPORT¶
Bugs should be reported via the CPAN bug tracker at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ORLite-Mirror
<
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ORLite-Mirror>
For other issues, contact the author.
AUTHOR¶
Adam Kennedy <adamk@cpan.org>
COPYRIGHT¶
Copyright 2008 - 2012 Adam Kennedy.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included with this
module.