File Coverage

blib/lib/DataWarehouse/Aggregate.pm

Criterion	Covered	Total	%
statement	10	12	83.3
branch			n/a
condition			n/a
subroutine	4	4	100.0
pod			n/a
total	14	16	87.5

package DataWarehouse::Aggregate;

use warnings;
use strict;

use Carp;
use DBI;

sub new {
    my ( $class, %params ) = @_;

    croak "Error: One of 'dbh' or 'dsn' parameters is required" if !($params{dbh} xor $params{dsn});
    croak "Error: missing base_table" if !$params{base_table};
    croak "Error: missing dimension"  if !$params{dimension};

    if ( $params{dsn} ) {
        $params{dbh} = DBI->connect( $params{dsn}, $params{db_user}, $params{db_password} ),;
    }

    bless {%params}, $class;
}

sub dimension {
    my ($self) = @_;

    my $dimension = $self->{dimension};

    if ( ref $dimension eq 'ARRAY' ) {
        return @{$dimension};
    }

    return $dimension;
}

sub name {
    my ($self) = @_;

    my $base_table = $self->{base_table};
    my @dimensions = $self->dimension;

    my $name = "aggr_" . $self->{base_table} . "_" . join( '_', sort @dimensions );

    return $name;
}

sub create {
    my ($self) = @_;

    my $base_table = $self->{base_table};
    my @dimensions = $self->dimension;
    my $aggr_name  = $self->name;

    my $sql = <<"SQL";
CREATE TABLE IF NOT EXISTS $aggr_name AS
    SELECT
        @{[ join(', ', @dimensions ) ]},
        SUM(n) AS n
    FROM
        $base_table
    JOIN
@{[ join(",\n", map { $self->_join_str($_) } @dimensions) ]}
GROUP BY
    @{[ join(", ", @dimensions) ]}
SQL

    warn "Creating aggregate...\n";
    warn $sql;
    my $dbh = $self->{dbh};
    $dbh->do($sql);
    warn "done\n";

    return $self;
}

sub list {
}

sub _join_str {
    my ( $self, $dim_table ) = @_;
    my $fact_table = $self->{base_table};
    return "    $dim_table ON $fact_table.$dim_table = $dim_table.id";
}

1;

__END__