NAME

Alzabo::Runtime::Row - Row objects

SYNOPSIS

  use Alzabo::Runtime::Row;

  ... or ...

  use Alzabo::Runtime::Row qw(MyCaching::Class);

DESCRIPTION

These objects represent actual rows from the database containing actual data. They can be created via their new method or via an Alzabo::Runtime::Table object.

CACHING

This module attempts to use the Alzabo::ObjectCache module if it has already been loaded when a new row is created. It will use the cache to store objects after they are created as well as using it check object expiration and deletion.

In addition, using the cache allows the object to cache the results of column fetches. This is an additional performance gain.

METHODS

new

Parameters

• table => Alzabo::Runtime::Table object

• id => (see below)

• no_cache => 0 or 1

  The id parameter may be one of two things. If the table has only a single column primary key, it can be a simple scalar with the value of that primary key for this row.

  If the primary key is more than one column than it must be a hash reference containing column names and values such as:

    { pk_column1 => 1,
      pk_column2 => 'foo' }

Setting the no_cache parameter to true causes this particular row object to not interact with the cache at all. This can be useful if you know you will be creating a very large number of row objects all at once that you have no intention of re-using.

If your cache class attempts to synchronize itself across multiple processes (such as Alzabo::ObjectCacheIPC does), then it is highly recommended that you not do any operations that change data in the database (delete or update) with objects that were created with this parameter as it will probably cause problems.

Returns

A new Alzabo::Runtiem::Row object. It will attempt to retrieve the row from the cache first unless the no_cache parameter is true. If no object matches these values then an exception will be thrown.

Throws

Alzabo::Exception::NoSuchRow

get_data

Tells the row object to connect to the database and fetch the data for the row matching this row's primary key values. If a cache class is specified it attempts to fetch the data from the cache first.

select (@list_of_column_names)

Returns

Returns a list of values matching the specified columns in a list context. In scalar context it returns only a single value (the first column specified).

update (%hash_of_columns_and_values)

Given a hash of columns and values, attempts to update the database to and the object to represent these new values.

delete

Deletes the row from the RDBMS and the cache, if it exists.

id

Returns the row's id value as a string. This can be passed to the Alzabo::Runtime::Table->row_by_id method to recreate the row later.

table

Returns the Alzabo::Runtime::Table object that this row belongs to.

rows_by_foreign_key

Parameters

• foreign_key => Alzabo::Runtime::ForeignKey object

Given a foreign key object, this method returns a Alzabo::Runtime::RowCursor object for the rows in the table that the relationship is _to_, based on the value of the relevant column in the current row.

All other parameters given will be passed directly to the new method (such as the no_cache paremeter).

AUTHOR

Dave Rolsky, <autarch@urth.org>