NAME

       MQdb::DBObject - DESCRIPTION of Object

SYNOPSIS

       Root class for all objects in MappedQuery toolkit

DESCRIPTION

       Root object for toolkit and all derived subclasses.  All objects in the MappedQuery
       structure are designed to be persisted in a database. Here database is a more broad term
       and can be considered any object persistance systems.  Currently the toolkit works with
       SQL based systems but object databases or custom storage engines are possible.  Provides
       base common methods used by all objects.

AUTHOR

       Contact Jessica Severin: jessica.severin@gmail.com

LICENSE

        * Software License Agreement (BSD License)
        * MappedQueryDB [MQdb] toolkit
        * copyright (c) 2006-2009 Jessica Severin
        * All rights reserved.
        * Redistribution and use in source and binary forms, with or without
        * modification, are permitted provided that the following conditions are met:
        *     * Redistributions of source code must retain the above copyright
        *       notice, this list of conditions and the following disclaimer.
        *     * Redistributions in binary form must reproduce the above copyright
        *       notice, this list of conditions and the following disclaimer in the
        *       documentation and/or other materials provided with the distribution.
        *     * Neither the name of Jessica Severin nor the
        *       names of its contributors may be used to endorse or promote products
        *       derived from this software without specific prior written permission.
        *
        * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
        * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
        * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
        * DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS BE LIABLE FOR ANY
        * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
        * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
        * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
        * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
        * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
        * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

APPENDIX

       The rest of the documentation details each of the object methods.  Internal methods are
       usually preceded with a _

   new
         Description: instance creation method
         Returntype : instance of this Class (subclass)
         Exceptions : none

   init
         Description: initialization method which subclasses can extend
         Returntype : $self
         Exceptions : subclass dependent

   copy
         Description: Shallow copy which copies all base attributes of object
                      to new instance of same class
         Returntype : same as calling instance
         Exceptions : subclass dependent

   class
         Description: fixed string symbol for this class. Must be implemented
                      for each subclass and each subclass within toolkit
                      should return a unique name. used by global  methods.
         Returntype : string
         Exceptions : error if subclass does not redefine

   database
         Description: the MQdb::Database where this object is permanently persisted to.
                      Here database is any object persistance system.
         Returntype : MQdb::Database
         Exceptions : die if invalid setter value type is provided

   primary_id
         Description: the unique identifier for this object within database.
         Returntype : scalar or UNDEF
         Exceptions : none

   id
         Description: the unique identifier for this object within database.
                      Returns empty string if not persisted.
         Returntype : scalar or ''
         Exceptions : none

   db_id
         Description: the worldwide unique identifier for this object.
                      A URL-like combination of database, class, and id
         Returntype : string or undef if database is not defined
         Exceptions : none

   display_desc
         Description: general purpose debugging method that returns a nice
                      human readable description of the object instance contents.
                      Each subclass should implement and return a nice string.
         Returntype : string scalar
         Exceptions : none

   display_info
         Description: convenience method which prints the display_desc string
                      with a carriage return to STDOUT. useful for debugging.
         Returntype : none
         Exceptions : none

   xml
         Description: every object in system should be persistable in XML format.
                      returns an XML description of the object and all child objects.
                      Each subclass must implement and return a proper XML string.
                      Best if one implements xml_start() and xml_end() and use here.
         Returntype : string scalar
         Exceptions : none
         Default    : default is a simple xml_start + xml_end

   xml_start
         Description: every object in system should be persistable in XML format.
                      returns an XML description of the object and all child objects.
                      Each subclass should OVERRIDE this method and return a proper XML string.
                      xml_start is the primary XML start tag
         Example    : return sprintf("<feature id='%d' name='%d' ..... >", $id, $name....);
         Returntype : string scalar
         Exceptions : none

   xml_end
         Description: every object in system should be persistable in XML format.
                      returns an XML description of the object and all child objects.
                      Each subclass should OVERRIDE this method and return a proper XML string.
                      xml_end is the primary XML end tag
         Example    : return "</feature>";
         Returntype : string scalar
         Exceptions : none

   simple_xml
         Description: short hand for xml_start() . xml_end()
                      Can be used when only the primary XML start tag and attributes are needed
                      No need to override if xml_start() and xml_end() are implemented
         Returntype : string scalar
         Exceptions : none