/ 
CPANDB-0.19
River stage one • 1 direct dependent • 1 total dependent
/ CPANDB::Dependency

NAME

CPANDB::Dependency - CPANDB class for the dependency table

DESCRIPTION

TO BE COMPLETED

METHODS

base

# Returns 'CPANDB'
my $namespace = CPANDB::Dependency->base;

Normally you will only need to work directly with a table class, and only with one ORLite package.

However, if for some reason you need to work with multiple ORLite packages at the same time without hardcoding the root namespace all the time, you can determine the root namespace from an object or table class with the base method.

table

# Returns 'dependency'
print CPANDB::Dependency->table;

While you should not need the name of table for any simple operations, from time to time you may need it programatically. If you do need it, you can use the table method to get the table name.

load

my $object = CPANDB::Dependency->load( $distribution );

If your table has single column primary key, a load method will be generated in the class. If there is no primary key, the method is not created.

The load method provides a shortcut mechanism for fetching a single object based on the value of the primary key. However it should only be used for cases where your code trusts the record to already exists.

It returns a CPANDB::Dependency object, or throws an exception if the object does not exist.

select

# Get all objects in list context
my @list = CPANDB::Dependency->select;

# Get a subset of objects in scalar context
my $array_ref = CPANDB::Dependency->select(
    'where distribution > ? order by distribution',
    1000,
);

The select method executes a typical SQL SELECT query on the dependency table.

It takes an optional argument of a SQL phrase to be added after the FROM dependency section of the query, followed by variables to be bound to the placeholders in the SQL phrase. Any SQL that is compatible with SQLite can be used in the parameter.

Returns a list of CPANDB::Dependency objects when called in list context, or a reference to an ARRAY of CPANDB::Dependency objects when called in scalar context.

Throws an exception on error, typically directly from the DBI layer.

iterate

CPANDB::Dependency->iterate( sub {
    print $_->distribution . "\n";
} );

The iterate method enables the processing of large tables one record at a time without loading having to them all into memory in advance.

This plays well to the strength of SQLite, allowing it to do the work of loading arbitrarily large stream of records from disk while retaining the full power of Perl when processing the records.

The last argument to iterate must be a subroutine reference that will be called for each element in the list, with the object provided in the topic variable $_.

This makes the iterate code fragment above functionally equivalent to the following, except with an O(1) memory cost instead of O(n).

foreach ( CPANDB::Dependency->select ) {
    print $_->distribution . "\n";
}

You can filter the list via SQL in the same way you can with select.

CPANDB::Dependency->iterate(
    'order by ?', 'distribution',
    sub {
        print $_->distribution . "\n";
    }
);

You can also use it in raw form from the root namespace for better control. Using this form also allows for the use of arbitrarily complex queries, including joins. Instead of being objects, rows are provided as ARRAY references when used in this form.

CPANDB->iterate(
    'select name from dependency order by distribution',
    sub {
        print $_->[0] . "\n";
    }
);

count

# How many objects are in the table
my $rows = CPANDB::Dependency->count;

# How many objects 
my $small = CPANDB::Dependency->count(
    'where distribution > ?',
    1000,
);

The count method executes a SELECT COUNT(*) query on the dependency table.

It takes an optional argument of a SQL phrase to be added after the FROM dependency section of the query, followed by variables to be bound to the placeholders in the SQL phrase. Any SQL that is compatible with SQLite can be used in the parameter.

Returns the number of objects that match the condition.

Throws an exception on error, typically directly from the DBI layer.

ACCESSORS

distribution

if ( $object->distribution ) {
    print "Object has been inserted\n";
} else {
    print "Object has not been inserted\n";
}

Returns true, or throws an exception on error.

REMAINING ACCESSORS TO BE COMPLETED

SQL

The dependency table was originally created with the following SQL command.

CREATE TABLE dependency (
    distribution TEXT NOT NULL,
    dependency TEXT NOT NULL,
    phase TEXT NOT NULL,
    core REAL NULL,
    PRIMARY KEY (distribution,
    dependency,
    phase),
    FOREIGN KEY (distribution) REFERENCES distribution (distribution),
    FOREIGN KEY (dependency) REFERENCES distribution (distribution)
)

SUPPORT

CPANDB::Dependency is part of the CPANDB API.

See the documentation for CPANDB for more information.

AUTHOR

Adam Kennedy <adamk@cpan.org>

COPYRIGHT

Copyright 2009 - 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.