ObjectDB - usable ORM
package MyDB; use base 'ObjectDB'; sub init_db { ... return $dbh; } package MyAuthor; use base 'MyDB'; __PACKAGE__->meta( table => 'author', columns => [qw/id name/], primary_key => 'id', auto_increment => 'id', relationships => { books => { type = 'one to many', class => 'MyBook', map => {id => 'author_id'} } } ); package MyBook; use base 'MyDB'; __PACKAGE__->meta( table => 'book', columns => [qw/id author_id title/], primary_key => 'id', auto_increment => 'id', 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');
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
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');
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.
create
Creates a new row. If meta has an auto_increment column then it is properly set.
meta
auto_increment
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;
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 in a row object for convenience.
table
find
MyBook->table->delete; # deletes ALL records from MyBook
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']);
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.
rollback
commit
MyDB->txn( sub { ... do smth that can throw ... } );
txn's return value is preserved, so it is safe to do something like:
txn
my $result = MyDB->txn( sub { return 'my result'; } );
Accepts a subroutine reference, wraps code into eval and runs it rethrowing all exceptions.
Commit transaction.
Rollback transaction.
Returns meta object. See ObjectDB::Meta.
ObjectDB::Meta
init_db
Returns current DBI instance.
DBI
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.
Viacheslav Tykhanovskyi
Copyright 2013, Viacheslav Tykhanovskyi.
This module is free software, you may distribute it under the same terms as Perl.
To install ObjectDB, copy and paste the appropriate command in to your terminal.
cpanm
cpanm ObjectDB
CPAN shell
perl -MCPAN -e shell install ObjectDB
For more information on module installation, please visit the detailed CPAN module installation guide.