MARC::Record(3pm)

1MARC::Record(3)       User Contributed Perl Documentation      MARC::Record(3)
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NAME

6       MARC::Record - Perl extension for handling MARC records
7

VERSION

9       Version 2.0.0
10

DESCRIPTION

12       Module for handling MARC records as objects.  The file-handling stuff
13       is in MARC::File::*.
14

ERROR HANDLING

16       Any errors generated are stored in $MARC::Record::ERROR.  Warnings are
17       kept with the record and accessible in the "warnings()" method.
18

CONSTRUCTORS

20   new()
21       Base constructor for the class.  It just returns a completely empty
22       record.  To get real data, you'll need to populate it with fields, or
23       use one of the MARC::File::* modules to read from a file.
24
25   new_from_usmarc( $marcblob [, \&filter_func($tagno,$tagdata)] )
26       This is a wrapper around "MARC::File::USMARC::decode()" for
27       compatibility with older versions of MARC::Record.
28
29       The "wanted_func()" is optional.  See MARC::File::USMARC::decode for
30       details.
31

COMMON FIELD RETRIEVAL METHODS

33       Following are a number of convenience methods for commonly-retrieved
34       data fields.  Please note that they each return strings, not
35       MARC::Field objects.  They return empty strings if the appropriate
36       field or subfield is not found.  This is as opposed to the
37       "field()"/"subfield()" methods which return "undef" if something's not
38       found.  My assumption is that these methods are used for quick & dirty
39       reports and you don't want to mess around with noting if something is
40       undef.
41
42       Also note that no punctuation cleanup is done.  If the 245a is
43       "Programming Perl / ", then that's what you'll get back, rather than
44       "Programming Perl".
45
46   title()
47       Returns the title from the 245 tag.
48
49   title_proper()
50       Returns the title proper from the 245 tag, subfields a, n and p.
51
52   author()
53       Returns the author from the 100, 110 or 111 tag.
54
55   edition()
56       Returns the edition from the 250 tag, subfield a.
57
58   publication_date()
59       Returns the publication date from the 260 tag, subfield c.
60

FIELD & SUBFIELD ACCESS METHODS

62   fields()
63       Returns a list of all the fields in the record. The list contains a
64       MARC::Field object for each field in the record.
65
66   field( tagspec(s) )
67       Returns a list of tags that match the field specifier, or an empty list
68       if nothing matched.  In scalar context, returns the first matching tag,
69       or undef if nothing matched.
70
71       The field specifier can be a simple number (i.e. "245"), or use the "."
72       notation of wildcarding (i.e. subject tags are "6..").
73
74   subfield( $tag, $subfield )
75       Shortcut method for getting just a subfield for a tag.  These are
76       equivalent:
77
78         my $title = $marc->field('245')->subfield("a");
79         my $title = $marc->subfield('245',"a");
80
81       If either the field or subfield can't be found, "undef" is returned.
82
83   append_fields( @fields )
84       Appends the field specified by $field to the end of the record.
85       @fields need to be MARC::Field objects.
86
87           my $field = MARC::Field->new('590','','','a' => 'My local note.');
88           $record->append_fields($field);
89
90       Returns the number of fields appended.
91
92   insert_fields_before( $before_field, @new_fields )
93       Inserts the field specified by $new_field before the field
94       $before_field.  Returns the number of fields inserted, or undef on
95       failures.  Both $before_field and all @new_fields need to be
96       MARC::Field objects.  If they are not an exception will be thrown.
97
98           my $before_field = $record->field('260');
99           my $new_field = MARC::Field->new('250','','','a' => '2nd ed.');
100           $record->insert_fields_before($before_field,$new_field);
101
102   insert_fields_after( $after_field, @new_fields )
103       Identical to "insert_fields_before()", but fields are added after
104       $after_field. Remember, $after_field and any new fields must be valid
105       MARC::Field objects or else an exception will be thrown.
106
107   insert_fields_ordered( @new_fields )
108       Will insert fields in strictly numerical order. So a 008 will be filed
109       after a 001 field. See "insert_grouped_field()" for an additional
110       ordering.
111
112   insert_grouped_field( $field )
113       Will insert the specified MARC::Field object into the record in grouped
114       order and return true (1) on success, and false (undef) on failure.
115
116           my $field = MARC::Field->new( '510', 'Indexed by Google.' );
117           $record->insert_grouped_field( $field );
118
119       For example, if a '650' field is inserted with "insert_grouped_field()"
120       it will be inserted at the end of the 6XX group of tags. After
121       discussion most people wanted the ability to add a new field to the end
122       of the hundred group where it belonged. The reason is that according to
123       the MARC format, fields within a record are supposed to be grouped by
124       block (hundred groups). This means that fields may not necessarily be
125       in tag order.
126
127   delete_field( $field )
128       Deletes a field from the record.
129
130       The field must have been retrieved from the record using the "field()"
131       method.  For example, to delete a 526 tag if it exists:
132
133           my $tag526 = $marc->field( "526" );
134           if ( $tag526 ) {
135               $marc->delete_field( $tag526 );
136           }
137
138       "delete_field()" returns the number of fields that were deleted.  This
139       shouldn't be 0 unless you didn't get the tag properly.
140
141   as_usmarc()
142       This is a wrapper around "MARC::File::USMARC::encode()" for
143       compatibility with older versions of MARC::Record.
144
145   as_formatted()
146       Returns a pretty string for printing in a MARC dump.
147
148   leader()
149       Returns the leader for the record.  Sets the leader if text is defined.
150       No error checking is done on the validity of the leader.
151
152   encoding()
153       A method for getting/setting the encoding for a record. The encoding
154       for a record is determined by position 09 in the leader, which is blank
155       for MARC-8 encoding, and 'a' for UCS/Unicode. encoding() will return a
156       string, either 'MARC-8' or 'UTF-8' appropriately.
157
158       If you want to set the encoding for a MARC::Record object you can use
159       the string values:
160
161           $record->encoding( 'UTF-8' );
162
163       NOTE: MARC::Record objects created from scratch have an a default
164       encoding of MARC-8, which has been the standard for years...but many
165       online catlogs and record vendors are migrating to UTF-8.
166
167       WARNING: you should be sure your record really does contain valid UTF-8
168       data when you manually set the encoding.
169
170   set_leader_lengths( $reclen, $baseaddr )
171       Internal function for updating the leader's length and base address.
172
173   clone()
174       The "clone()" method makes a copy of an existing MARC record and
175       returns the new version.  Note that you cannot just say:
176
177           my $newmarc = $oldmarc;
178
179       This just makes a copy of the reference, not a new object.  You must
180       use the "clone()" method like so:
181
182           my $newmarc = $oldmarc->clone;
183
184       You can also specify field specs to filter down only a certain subset
185       of fields.  For instance, if you only wanted the title and ISBN tags
186       from a record, you could do this:
187
188           my $small_marc = $marc->clone( 245, '020' );
189
190       The order of the fields is preserved as it was in the original record.
191
192   warnings()
193       Returns the warnings (as a list) that were created when the record was
194       read.  These are things like "Invalid indicators converted to blanks".
195
196           my @warnings = $record->warnings();
197
198       The warnings are items that you might be interested in, or might not.
199       It depends on how stringently you're checking data.  If you're doing
200       some grunt data analysis, you probably don't care.
201
202       A side effect of calling warnings() is that the warning buffer will be
203       cleared.
204
205   add_fields()
206       "add_fields()" is now deprecated, and users are encouraged to use
207       "append_fields()", "insert_fields_after()", and
208       "insert_fields_before()" since they do what you want probably. It is
209       still here though, for backwards compatability.
210
211       "add_fields()" adds MARC::Field objects to the end of the list.
212       Returns the number of fields added, or "undef" if there was an error.
213
214       There are three ways of calling "add_fields()" to add data to the
215       record.
216
217       1 Create a MARC::Field object and add it
218             my $author = MARC::Field->new(
219                           100, "1", " ", a => "Arnosky, Jim."
220                           );
221             $marc->add_fields( $author );
222
223       2 Add the data fields directly, and let "add_fields()" take care of the
224       objectifying.
225             $marc->add_fields(
226                   245, "1", "0",
227                           a => "Raccoons and ripe corn /",
228                           c => "Jim Arnosky.",
229                           );
230
231       3 Same as #2 above, but pass multiple fields of data in anonymous lists
232             $marc->add_fields(
233                   [ 250, " ", " ", a => "1st ed." ],
234                   [ 650, "1", " ", a => "Raccoons." ],
235                   );
236

DESIGN NOTES

238       A brief discussion of why MARC::Record is done the way it is:
239
240       ·   It's built for quick prototyping
241
242           One of the areas Perl excels is in allowing the programmer to
243           create easy solutions quickly.  MARC::Record is designed along
244           those same lines.  You want a program to dump all the 6XX tags in a
245           file?  MARC::Record is your friend.
246
247       ·   It's built for extensibility
248
249           Currently, I'm using MARC::Record for analyzing bibliographic data,
250           but who knows what might happen in the future?  MARC::Record needs
251           to be just as adept at authority data, too.
252
253       ·   It's designed around accessor methods
254
255           I use method calls everywhere, and I expect calling programs to do
256           the same, rather than accessing internal data directly.  If you
257           access an object's hash fields on your own, future releases may
258           break your code.
259
260       ·   It's not built for speed
261
262           One of the tradeoffs in using accessor methods is some overhead in
263           the method calls.  Is this slow?  I don't know, I haven't measured.
264           I would suggest that if you're a cycle junkie that you use
265           Benchmark.pm to check to see where your bottlenecks are, and then
266           decide if MARC::Record is for you.
267

RELATED MODULES

269       MARC::Field, MARC::Batch, MARC::File::XML, MARC::Charset, MARC::Lint
270

TODO

291       ·   Incorporate MARC.pm in the distribution.
292
293           Combine MARC.pm and MARC::* into one distribution.
294
295       ·   Podify MARC.pm
296
297       ·   Allow regexes across the entire tag
298
299           Imagine something like this:
300
301             my @sears_headings = $marc->tag_grep( qr/Sears/ );
302
303           (from Mike O'Regan)
304
305       ·   Insert a field in an arbitrary place in the record
306
307       ·   Modifying an existing field
308

BUGS, WISHES AND CORRESPONDENCE

310       Please feel free to email me at "<mrylander@gmail.com>".  I'm glad to
311       help as best I can, and I'm always interested in bugs, suggestions and
312       patches.
313
314       An excellent place to look for information, and get quick help, is from
315       the perl4lib mailing list.  See <http://perl4lib.perl.org> for more
316       information about this list, and other helpful MARC information.
317
318       The MARC::Record development team uses the RT bug tracking system at
319       <http://rt.cpan.org>.  If your email is about a bug or suggestion,
320       please report it through the RT system.  This is a huge help for the
321       team, and you'll be notified of progress as things get fixed or
322       updated.  If you prefer not to use the website, you can send your bug
323       to "<bug-MARC-Record@rt.cpan.org>"
324

IDEAS

326       Ideas are things that have been considered, but nobody's actually asked
327       for.
328
329       ·   Create multiple output formats.
330
331           These could be ASCII or MarcMaker.
332

LICENSE

334       This code may be distributed under the same terms as Perl itself.
335
336       Please note that these modules are not products of or supported by the
337       employers of the various contributors to the code.
338

AUTHOR

340       Andy Lester, "<andy@petdance.com>"
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344perl v5.12.0                      2007-01-25                   MARC::Record(3)