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Вячеслав Тихановский > ObjectDB > ObjectDB

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Module Version: 3.24   Source  

NAME ^

ObjectDB - usable ORM

SYNOPSIS ^

    package MyDB;
    use base 'ObjectDB';

    sub init_db {
        ...
        return $dbh;
    }

    package MyAuthor;
    use base 'MyDB';

    __PACKAGE__->meta(
        table                    => 'author',
        auto_increment           => 'id',
        discover_schema          => 1,
        generate_columns_methods => 1,
        generate_related_methods => 1,
        relationships            => {
            books => {
                type  => 'one to many',
                class => 'MyBook',
                map   => { id => 'author_id' }
            }
        }
    );

    package MyBook;
    use base 'MyDB';

    __PACKAGE__->meta(
        table                    => 'book',
        auto_increment           => 'id',
        discover_schema          => 1,
        generate_columns_methods => 1,
        generate_related_methods => 1,
        relationships            => {
            author => {
                type  => 'many to one',
                class => 'MyAuthor',
                map   => { author_id => 'id' }
            }
        }
    );

    my $book_by_id = MyBook->new(id => 1)->load(with => 'author');

    my @books_authored_by_Pushkin = MyBook->table->find(where => [ 'author.name' => 'Pushkin' ]);

    $author->create_related('books', title => 'New Book');

DESCRIPTION ^

ObjectDB is a lightweight and flexible object-relational mapper. While being light it stays usable. ObjectDB borrows many things from Rose::DB::Object, but unlike in the last one columns are not objects, everything is pretty much straightforward and flat.

Supported servers: SQLite, MySQL, PostgreSQL.

STABILITY ^

This module is used in several productions, under heavy load and big volumes.

PERFORMANCE ^

When performance is a must but you don't want to switch back to DBI take a look at find_by_compose, find_by_sql methods and at rows_as_hashes option in ObjectDB::Table.

Latest benchmarks

    # Create

              Rate create    DBI
    create 10204/s     --   -73%
    DBI    37975/s   272%     --

    # Select 1

                       Rate          find find_by_compose  find_by_sql           DBI
    find             4478/s            --            -36%         -80%          -91%
    find_by_compose  7042/s           57%              --         -69%          -86%
    find_by_sql     22556/s          404%            220%           --          -56%
    DBI             51724/s         1055%            634%         129%            --

    # Select many

                       Rate          find find_by_compose  find_by_sql           DBI
    find             5618/s            --            -21%         -76%          -89%
    find_by_compose  7109/s           27%              --         -69%          -86%
    find_by_sql     23077/s          311%            225%           --          -53%
    DBI             49180/s          775%            592%         113%            --

    # Select many with iterator

                             Rate find_by_sql find_by_compose  find
    find_by_sql            25.8/s          --            -18%  -19%
    find_by_compose        31.5/s         22%              --   -2%
    find                   32.1/s         24%              2%    --
    find_by_compose (hash)  201/s        677%            537%  526%
    find (hash)             202/s        680%            539%  528%
    find_by_sql (hash)      415/s       1505%           1215% 1193%
    DBI                    1351/s       5128%           4184% 4109%

                             find_by_compose (hash) find (hash) find_by_sql (hash)  DBI
    find_by_sql                                -87%        -87%               -94% -98%
    find_by_compose                            -84%        -84%               -92% -98%
    find                                       -84%        -84%               -92% -98%
    find_by_compose (hash)                       --         -0%               -52% -85%
    find (hash)                                  0%          --               -51% -85%
    find_by_sql (hash)                         107%        106%                 -- -69%
    DBI                                        573%        570%               226%   --

Meta auto discovery and method generation

When you have DBIx::Inspector installed meta can be automatically discovered without the need to specify columns. And special methods for columns and relationships are automatically generated.

Actions on columns

Methods

set_columns

Set columns.

    $book->set_columns(title => 'New Book', pages => 140);
set_column

Set column.

    $book->set_column(title => 'New Book');
get_column
    my $title = $book->get_column('title');
column

A shortcut for set_column/get_column.

    $book->column(title => 'New Book');
    my $title = $book->column('title');

Actions on rows

Main ObjectDB instance represents a row object. All actions performed on this instance are performed on one row. For performing actions on several rows see ObjectDB::Table.

Methods

create

Creates a new row. If meta has an auto_increment column then it is properly set.

    my $author = MyAuthor->new(name => 'Me')->create;

It is possible to create related objects automatically:

    my $author = MyAuthor->new(
        name  => 'Me',
        books => [{title => 'Book1'}, {title => 'Book2'}]
    )->create;

Which is a convenient way of calling C <create_related> manually .

load

Loads an object by primary or unique key.

    my $author = MyAuthor->new(id => 1)->load;

It is possible to load an object with related objects.

    my $book = MyBook->new(title => 'New Book')->load(with => 'author');
update

Updates an object.

    $book->set_column(title => 'Old Title');
    $book->update;
delete

Deletes an object. Related objects are NOT deleted.

    $book->delete;

Actions on tables

In order to perform an action on table a ObjectDB::Table object must be obtained via table method (see ObjectDB::Table for all available actions). The only exception is find, it is available on a row object for convenience.

    MyBook->table->delete; # deletes ALL records from MyBook

Actions on related objects

Methods

related

Returns preloaded related objects or loads them on demand.

    # same as find_related but with caching
    my $description = $book->related('book_description');

    # returns from cache
    my $description = $book->related('book_description');
create_related

Creates related object, setting appropriate foreign keys. Accepts a list, a hash reference, an object.

    $author->create_related('books', title => 'New Book');
    $author->create_related('books', MyBook->new(title => 'New Book'));
find_related

Finds related object.

    my $books = $author->find_related('books', where => [title => 'New Book']);
update_related

Updates related object.

    $author->update_related(
        'books',
        set   => {title => 'Old Book'},
        where => [title => 'New Book']
    );
delete_related

Deletes related object.

    $author->delete_related('books', where => [title => 'New Book']);

Transactions

All the exceptions will be catched, a rollback will be run and exceptions will be rethrown. It is safe to use rollback or commit inside of a transaction when you want to do custom exception handling.

    MyDB->txn(
        sub {
            ... do smth that can throw ...
        }
    );

txn's return value is preserved, so it is safe to do something like:

    my $result = MyDB->txn(
        sub {
            return 'my result';
        }
    );

Methods

txn

Accepts a subroutine reference, wraps code into eval and runs it rethrowing all exceptions.

commit

Commit transaction.

rollback

Rollback transaction.

Utility methods

Methods

meta

Returns meta object. See ObjectDB::Meta.

init_db

Returns current DBI instance.

is_modified

Returns 1 if object is modified.

is_in_db

Returns 1 if object is in database.

is_related_loaded

Checks if related objects are loaded.

clone

Clones object preserving all columns except primary or unique keys.

to_hash

Converts object into a hash reference, including all preloaded objects.

AUTHOR ^

Viacheslav Tykhanovskyi

COPYRIGHT AND LICENSE ^

Copyright 2013-2017, Viacheslav Tykhanovskyi.

This module is free software, you may distribute it under the same terms as Perl.

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