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 2.0.7
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 compatibility
27       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_fields( $field )
128       Deletes a given list of MARC::Field objects from the the record.
129
130           # delete all note fields
131           my @notes = $record->field('5..');
132           $record->delete_fields(@notes);
133
134       delete_fields() will return the number of fields that were deleted.
135
136   delete_field()
137       Same thing as delete_fields() but only expects a single MARC::Field to
138       be passed in. Mainly here for backwards compatibility.
139
140   as_usmarc()
141       This is a wrapper around MARC::File::USMARC::encode() for compatibility
142       with older versions of MARC::Record.
143
144   as_formatted()
145       Returns a pretty string for printing in a MARC dump.
146
147   leader()
148       Returns the leader for the record.  Sets the leader if text is defined.
149       No error checking is done on the validity of the leader.
150
151   encoding()
152       A method for getting/setting the encoding for a record. The encoding
153       for a record is determined by position 09 in the leader, which is blank
154       for MARC-8 encoding, and 'a' for UCS/Unicode. encoding() will return a
155       string, either 'MARC-8' or 'UTF-8' appropriately.
156
157       If you want to set the encoding for a MARC::Record object you can use
158       the string values:
159
160           $record->encoding( 'UTF-8' );
161
162       NOTE: MARC::Record objects created from scratch have an a default
163       encoding of MARC-8, which has been the standard for years...but many
164       online catlogs and record vendors are migrating to UTF-8.
165
166       WARNING: you should be sure your record really does contain valid UTF-8
167       data when you manually set the encoding.
168
169   set_leader_lengths( $reclen, $baseaddr )
170       Internal function for updating the leader's length and base address.
171
172   clone()
173       The clone() method makes a copy of an existing MARC record and returns
174       the new version.  Note that you cannot just say:
175
176           my $newmarc = $oldmarc;
177
178       This just makes a copy of the reference, not a new object.  You must
179       use the clone() method like so:
180
181           my $newmarc = $oldmarc->clone;
182
183       You can also specify field specs to filter down only a certain subset
184       of fields.  For instance, if you only wanted the title and ISBN tags
185       from a record, you could do this:
186
187           my $small_marc = $marc->clone( 245, '020' );
188
189       The order of the fields is preserved as it was in the original record.
190
191   warnings()
192       Returns the warnings (as a list) that were created when the record was
193       read.  These are things like "Invalid indicators converted to blanks".
194
195           my @warnings = $record->warnings();
196
197       The warnings are items that you might be interested in, or might not.
198       It depends on how stringently you're checking data.  If you're doing
199       some grunt data analysis, you probably don't care.
200
201       A side effect of calling warnings() is that the warning buffer will be
202       cleared.
203
204   add_fields()
205       add_fields() is now deprecated, and users are encouraged to use
206       append_fields(), insert_fields_after(), and insert_fields_before()
207       since they do what you want probably. It is still here though, for
208       backwards compatibility.
209
210       add_fields() adds MARC::Field objects to the end of the list.  Returns
211       the number of fields added, or "undef" if there was an error.
212
213       There are three ways of calling add_fields() to add data to the record.
214
215       1 Create a MARC::Field object and add it
216             my $author = MARC::Field->new(
217                           100, "1", " ", a => "Arnosky, Jim."
218                           );
219             $marc->add_fields( $author );
220
221       2 Add the data fields directly, and let add_fields() take care of the
222       objectifying.
223             $marc->add_fields(
224                   245, "1", "0",
225                           a => "Raccoons and ripe corn /",
226                           c => "Jim Arnosky.",
227                           );
228
229       3 Same as #2 above, but pass multiple fields of data in anonymous lists
230             $marc->add_fields(
231                   [ 250, " ", " ", a => "1st ed." ],
232                   [ 650, "1", " ", a => "Raccoons." ],
233                   );
234

DESIGN NOTES

236       A brief discussion of why MARC::Record is done the way it is:
237
238       •   It's built for quick prototyping
239
240           One of the areas Perl excels is in allowing the programmer to
241           create easy solutions quickly.  MARC::Record is designed along
242           those same lines.  You want a program to dump all the 6XX tags in a
243           file?  MARC::Record is your friend.
244
245       •   It's built for extensibility
246
247           Currently, I'm using MARC::Record for analyzing bibliographic data,
248           but who knows what might happen in the future?  MARC::Record needs
249           to be just as adept at authority data, too.
250
251       •   It's designed around accessor methods
252
253           I use method calls everywhere, and I expect calling programs to do
254           the same, rather than accessing internal data directly.  If you
255           access an object's hash fields on your own, future releases may
256           break your code.
257
258       •   It's not built for speed
259
260           One of the tradeoffs in using accessor methods is some overhead in
261           the method calls.  Is this slow?  I don't know, I haven't measured.
262           I would suggest that if you're a cycle junkie that you use
263           Benchmark.pm to check to see where your bottlenecks are, and then
264           decide if MARC::Record is for you.
265

RELATED MODULES

267       MARC::Field, MARC::Batch, MARC::File::XML, MARC::Charset, MARC::Lint
268

TODO

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

BUGS, WISHES AND CORRESPONDENCE

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

IDEAS

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

LICENSE

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

AUTHORS

339       •   Andy Lester
340
341       •   Mike O'Regan
342
343       •   Ed Summers
344
345       •   Mike Rylander
346
347       •   Galen Charlton
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351perl v5.38.0                      2023-07-20                   MARC::Record(3)