NAME
Database::Abstraction - database abstraction layer
VERSION
Version 0.04
SYNOPSIS
Abstract class giving read-only access to CSV, XML and SQLite databases via Perl without writing any SQL. Look for databases in $directory in this order: 1) SQLite (file ends with .sql) 2) PSV (pipe separated file, file ends with .psv) 3) CSV (file ends with .csv or .db, can be gzipped) 4) XML (file ends with .xml)
For example, you can access the files in /var/db/foo.csv via this class:
package MyPackageName::Database::Foo;
use Database::Abstraction;
our @ISA = ('Database::Abstraction');
1;You can then access the data using:
my $foo = MyPackageName::Database::Foo->new(directory => '/var/db');
print 'Customer name ', $foo->name(customer_id => 'plugh');
my $row = $foo->fetchrow_hashref(customer_id => 'xyzzy');
print Data::Dumper->new([$row])->Dump();CSV files can have empty lines or comment lines starting with '#', to make them more readable.
If the table has a column called "entry", sorts are based on that To turn that off, pass 'no_entry' to the constructor, for legacy reasons it's enabled by default
SUBROUTINES/METHODS
init
Set some class level defaults.
MyPackageName::Database::init(directory => '../databases');See the documentation for new() to see what variables can be set.
Returns a refernce to a hash of the current values.
new
Create an object to point to a read-only database.
Arguments:
cache => place to store results; cache_duration => how long to store results in the cache (default is 1 hour); directory => where the database file is held
If the arguments are not set, tries to take from class level defaults.
set_logger
Pass a class that will be used for logging
selectall_hashref
Returns a reference to an array of hash references of all the data meeting the given criteria
selectall_hash
Returns an array of hash references
fetchrow_hashref
Returns a hash reference for one row in a table. Special argument: table: determines the table to read from if not the default, which is worked out from the class name
execute
Execute the given SQL on the data. In an array context, returns an array of hash refs, in a scalar context returns a hash of the first row
updated
Time that the database was last updated
AUTOLOAD
Return the contents of an arbitrary column in the database which match the given criteria Returns an array of the matches, or just the first entry when called in scalar context
If the first column if the database is "entry" you can do a quick lookup with my $value = $table->column($entry); # where column is the value you're after
Set distinct to 1 if you're after a unique list
AUTHOR
Nigel Horne, <njh at bandsman.co.uk>
BUGS
The default delimiter for CSV files is set to '!', not ',' for historical reasons. I really ought to fix that.
LICENSE AND COPYRIGHT
Copyright 2015-2024 Nigel Horne.
This program is released under the following licence: GPL2. Usage is subject to licence terms. The licence terms of this software are as follows: Personal single user, single computer use: GPL2 All other users (for example Commercial, Charity, Educational, Government) must apply in writing for a licence for use from Nigel Horne at the above e-mail.