NAME

DBIx::EAV - Entity-Attribute-Value data modeling (aka 'open schema') for Perl

SYNOPSIS

#!/usr/bin/env perl
use strict;
use warnings;
use DBIx::EAV;

# connect to the database
my $eav = DBIx::EAV->connect("dbi:SQLite:database=:memory:");

# or
# $eav = DBIx::EAV->new( dbh => $dbh, %constructor_params );

# create eav tables
$eav->schema->deploy;

# register entities
$eav->register_types({
    Artist => {
        many_to_many => 'CD',
        has_many     => 'Review',
        attributes   => [qw/ name:varchar description:text rating:int birth_date:datetime /]
    },

    CD => {
        has_many     => ['Track', 'Review'],
        has_one      => ['CoverImage'],
        attributes   => [qw/ title description:text rating:int /]
    },

    Track => {
        attributes   => [qw/ title description:text duration:int /]
    },

    CoverImage => {
        attributes   => [qw/ url /]
    },

    Review => {
        attributes => [qw/ content:text views:int likes:int dislikes:int /]
    },
});


# insert data (and possibly related data)
my $bob = $eav->resultset('Artist')->insert({
    name => 'Robert',
    description => '...',
    cds => [
        { title => 'CD1', rating => 5 },
        { title => 'CD2', rating => 6 },
        { title => 'CD3', rating => 8 },
        { title => 'CD4', rating => 9 },
    ]
 });

# get attributes
print $bob->get('name'); # Robert

# update name
$bob->update({ name => 'Bob' });

# add more cds
$bob->add_related('cds', { title => 'CD5', rating => 7 });

# get Bob's cds via auto-generated 'cds' relationship
print "\nAll Bob CDs:\n";
printf " - %s (rating %d)\n", $_->get('title'), $_->get('rating')
    foreach $bob->get('cds');

print "\nBest Bob CDs:\n";
printf " - %s (rating %d)\n", $_->get('title'), $_->get('rating')
    foreach $bob->get('cds', { rating => { '>' => 7 } });


# ResultSets ...


# retrieve Bob from database
$bob = $eav->resultset('Artist')->find({ name => 'Bob' });

# retrieve Bob's cds directly from CD resultset
# note the use of 'artists' relationship automaticaly created
# from the "Artist many_to_many CD" declaration
my @cds = $eav->resultset('CD')->search({ artists => $bob });

# same as above
@cds = $bob->get('cds');

# or traverse the cds using the resultset cursor
my $cds_rs = $bob->get('cds');

while (my $cd = $cds_rs->next) {
    print $cd->get('title');
}

# delete all cds
$eav->resultset('CD')->delete;

# delete all cds and related data (i.e. tracks)
$eav->resultset('CD')->delete_all;

DESCRIPTION

An implementation of Entity-Attribute-Value data modeling with support for entity relationships and multi-tenancy.

ALPHA STAGE

This project is in its infancy, and the main purpose of this stage is to let other developers try it, and help identify any major design flaw before we can stabilize the API. One exception is the ResultSet whose API (and docs :]) I've borrowed from DBIx::Class, so its (API is) already stable.

CONSTRUCTORS

new

Arguments: %params

Valid %params keys:

dbh (required)

Existing DBI database handle. See "connect".

schema_config

Hashref of options used to instantiate our DBIx::EAV::Schema. See "CONSTRUCTOR OPTIONS" in DBIx::EAV::Schema.

connect

Arguments: $dsn, $user, $pass, $attrs, \%constructor_params

Connects to the database via DBI->connect($dsn, $user, $pass, $attrs) then returns a new instance via new(\%constructor_params).

METHODS

register_types

Arguments: \%schema

Return value: none

Registers entity types specified in \%schema, where each key is the name of the type and the value is a hashref describing its attributes and relationships. Fully described in "ENTITY DEFINITION" in DBIx::EAV::EntityType.

This method ignores types already installed, allowing code that registers types to live close to the code that actually uses the types.

When registering types already registered, additional attributes and relationships are registered accordingly. To delete attributes and values see "PRUNING" in DBIx::EAV::EntityType.

See "INSTALLED VS REGISTERED TYPES".

resultset

Arguments: $name

Return value: $rs

Returns a new resultset instance for type $name.

my $rs = $eav->resultset('Artist');

type

Arguments: $name

Returns the DBIx::EAV::EntityType instance for type $name. If the type instance is not already installed in this DBIx::EAV instance, we try to load the type definition from the database. Dies if type is not registered.

my $types = $eav->type('Artist');

See "INSTALLED VS REGISTERED TYPES".

has_type

Arguments: $name

Returns true if entity type $name is installed.

schema

Returns the DBIx::EAV::Schema instance representing the physical database schema.

table

Shortcut for ->schema->table.

Arguments: $name

Returns true if the data type $name exists. See "data_types".

dbh_do

Arguments: $stmt, \@bind?

Return Values: ($rv, $sth)

Prepares $stmt and executes with the optional \@bind values. Returns the return value from execute $rv and the actual statement handle $sth object.

Set environment variable DBIX_EAV_TRACE to 1 to get statements printed to STDERR.

INSTALLED VS REGISTERED TYPES

LICENSE

Copyright (C) Carlos Fernando Avila Gratz.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

Carlos Fernando Avila Gratz <cafe@kreato.com.br>

cpanm DBIx::EAV

perl -MCPAN -e shell
install DBIx::EAV