Bio::Annotation::DBLink - untyped links between databases


   $link1 = Bio::Annotation::DBLink->new(-database => 'TSC',
                                        -primary_id => 'TSC0000030'


   $link2 = Bio::Annotation::DBLink->new();

   # DBLink is-a Bio::AnnotationI object, can be added to annotation
   # collections, e.g. the one on features or seqs
   $feat->annotation->add_Annotation('dblink', $link2);


Provides an object which represents a link from one object to something in another database without prescribing what is in the other database.

Aside from Bio::AnnotationI, this class also implements Bio::IdentifiableI.

AUTHOR - Ewan Birney

Ewan Birney -


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


 Title   : new
 Usage   : $dblink = Bio::Annotation::DBLink->new(-database =>"GenBank",
                                                  -primary_id => "M123456");
 Function: Creates a new instance of this class.
 Example :
 Returns : A new instance of Bio::Annotation::DBLink.
 Args    : Named parameters. At present, the following parameters are

             -database    the name of the database referenced by the xref
             -primary_id  the primary (main) id of the referenced entry
                          (usually this will be an accession number)
             -optional_id a secondary ID under which the referenced entry
                          is known in the same database
             -comment     comment text for the dbxref
             -tagname     the name of the tag under which to add this
                          instance to an annotation bundle (usually 'dblink')
             -type        the type of information in the referenced entry
                          (e.g. protein, mRNA, structure)
             -namespace   synonymous with -database (also overrides)
             -version     version of the referenced entry
             -authority   attribute of the Bio::IdentifiableI interface
             -url         attribute of the Bio::IdentifiableI interface

AnnotationI implementing functions


 Title   : as_text
 Usage   :
 Example :
 Returns : 
 Args    :


 Title   : display_text
 Usage   : my $str = $ann->display_text();
 Function: returns a string. Unlike as_text(), this method returns a string
           formatted as would be expected for te specific implementation.

           One can pass a callback as an argument which allows custom text
           generation; the callback is passed the current instance and any text
 Example :
 Returns : a string
 Args    : [optional] callback


 Title   : hash_tree
 Usage   :
 Example :
 Returns : 
 Args    :


 Title   : tagname
 Usage   : $obj->tagname($newval)
 Function: Get/set the tagname for this annotation value.

           Setting this is optional. If set, it obviates the need to
           provide a tag to Bio::AnnotationCollectionI when adding
           this object. When obtaining an AnnotationI object from the
           collection, the collection will set the value to the tag
           under which it was stored unless the object has a tag
           stored already.

 Example : 
 Returns : value of tagname (a scalar)
 Args    : new value (a scalar, optional)

Specific accessors for DBLinks


 Title   : database
 Usage   : $self->database($newval)
 Function: set/get on the database string. Databases are just
           a string here which can then be interpreted elsewhere
 Example : 
 Returns : value of database
 Args    : newvalue (optional)


 Title   : primary_id
 Usage   : $self->primary_id($newval)
 Function: set/get on the primary id (a string)
           The primary id is the main identifier used for this object in 
           the database. Good examples would be accession numbers. The id
           is meant to be the main, stable identifier for this object
 Example : 
 Returns : value of primary_id
 Args    : newvalue (optional)


 Title   : optional_id
 Usage   : $self->optional_id($newval)
 Function: get/set for the optional_id (a string)

           optional id is a slot for people to use as they wish. The
           main issue is that some databases do not have a clean
           single string identifier scheme. It is hoped that the
           primary_id can behave like a reasonably sane "single string
           identifier" of objects, and people can use/abuse optional
           ids to their heart's content to provide precise mappings.

 Example : 
 Returns : value of optional_id
 Args    : newvalue (optional)


 Title   : comment
 Usage   : $self->comment($newval)
 Function: get/set of comments (comment object)
           Sets or gets comments of this dblink, which is sometimes relevant
 Example : 
 Returns : value of comment (Bio::Annotation::Comment)
 Args    : newvalue (optional)


 Title   : type
 Usage   : $self->type($newval)
 Function: get/set of type
           Sets or gets the type of this dblink.
 Example : $self->type('protein')
 Returns : value of type
 Args    : newvalue (optional)

Methods for Bio::IdentifiableI compliance


 Title   : object_id
 Usage   : $string    = $obj->object_id()
 Function: a string which represents the stable primary identifier
           in this namespace of this object. For DNA sequences this
           is its accession_number, similarly for protein sequences

           This is aliased to primary_id().
 Returns : A scalar


 Title   : version
 Usage   : $version    = $obj->version()
 Function: a number which differentiates between versions of
           the same object. Higher numbers are considered to be
           later and more relevant, but a single object described
           the same identifier should represent the same concept

 Returns : A number


 Title   : url
 Usage   : $url    = $obj->url()
 Function: URL which is associated with this DB link
 Returns : string, full URL descriptor


 Title   : authority
 Usage   : $authority    = $obj->authority()
 Function: a string which represents the organisation which
           granted the namespace, written as the DNS name for  
           organisation (eg,

 Returns : A scalar


 Title   : namespace
 Usage   : $string    = $obj->namespace()
 Function: A string representing the name space this identifier
           is valid in, often the database name or the name
           describing the collection 

           For DBLink this is the same as database().
 Returns : A scalar