NAME

VOTABLE::FIELD - VOTABLE FIELD XML element class

SYNOPSIS

use VOTABLE::FIELD;

DESCRIPTION

This class implements the FIELD element from the VOTABLE DTD. This class stores metadata for a single field (column) in a table.

The FIELD element is a Tier 3 element, and is described by the following excerpt from the VOTABLE 1.0 DTD:

 <!ELEMENT FIELD (DESCRIPTION?, VALUES*, LINK*)>
 <!ATTLIST FIELD
         ID ID #IMPLIED
         unit CDATA #IMPLIED
         datatype (boolean | bit | unsignedByte | short | int | long | char
        | unicodeChar | float | double | floatComplex | doubleComplex) #IMPLIED
         precision CDATA #IMPLIED
         width CDATA #IMPLIED
         ref IDREF #IMPLIED
         name CDATA #IMPLIED
         ucd CDATA #IMPLIED
         arraysize CDATA #IMPLIED
         type (hidden | no_query | trigger) #IMPLIED
 >

Methods

`new($xmldom_element, %options)`

Create and return a new VOTABLE::FIELD object, based on the supplied XML::DOM::Element object, using %options to set the attributes of the new object. If no XML::DOM::Element object is specified, or is undefined, create and return an empty VOTABLE::FIELD object. Return undef if an error occurs.

Method names that begin with a leading underscore ('_') are for internal use only, and should not be used outside of the VOTABLE class hierarchy.
The names of the get_XXX and set_XXX accessors for attributes and elements are derived directly from the names of the attributes or elements. Attribute and element names containing embedded hyphens ('-') use accessors where the hyphen is mapped to an underscore ('_') in the name of the accessor method. This is a necessity, since the hyphen is not a valid name character in Perl.

WARNINGS

This code (perhaps unwisely) assumes that object internal structure is always maintained. For example, this code assumes that every VOTABLE::TABLEDATA object always has an underlying XML::DOM::Element object. As long as the internal structure is manipulated only by the publicly-available methods, this should be an adequate assumption. If a method detects an aberrant case, a warning message is printed (using the Carp::carp subroutine), and the method fails.
Similarly, this code assumes that XML::DOM methods always succeed. If a method detects an aberrant case, a warning message is printed (using the Carp::carp subroutine), and the method fails.
Most attribute set_XXX accessors do not perform validation of the new attribute values. The exceptions are the accessors for attributes with enumerated values; the new value is checked against the list of acceptable values, as defined in the DTD.

AUTHOR

Eric Winter, NASA GSFC (elwinter@milkyway.gsfc.nasa.gov)

VERSION

$Id: FIELD.pm,v 1.1.1.8 2002/05/21 14:10:33 elwinter Exp $

NAME

SYNOPSIS

DESCRIPTION

Methods

`new($xmldom_element, %options)`

`get_ID`

`set_ID($id)`

`get_arraysize`

`set_arraysize($arraysize)`

`get_datatype`

`set_datatype($datatype)`

`get_name`

`set_name($name)`

`get_precision`

`set_precision($precision)`

`get_ref`

`set_ref($ref)`

`get_type`

`set_type($type)`

`get_ucd`

`set_ucd($ucd)`

`get_unit`

`set_unit($unit)`

`get_width`

`set_width($width)`

`get_description`

`set_description($votable_description)`

`get_link`

`set_link(@votable_link)`

`get_values`

`set_values(@votable_values)`

Notes on class internals

WARNINGS

SEE ALSO

AUTHOR

VERSION