What is MARC?

What is this Tutorial?

The document you are reading is distributed with the MARC::Record package, however in case you are reading it somewhere else, you can find the latest version at CPAN: http://www.cpan.org/modules/by-module/MARC/. You'll notice that some sections aren't filled in yet, which is a result of this document being a work in progress. If you have ideas for new sections please make a suggestion to perl4lib: https://perl4lib.perl.org/.

History of MARC on CPAN

In mid 2001, Andy Lester released MARC::Record and MARC::Field which provided a much simpler and maintainable package for processing MARC data with Perl. As its name suggests, MARC::Record treats an individual MARC record as the primary Perl object, rather than having the object represent a given set of records. Instead of forking the two projects, the developers agreed to encourage use of the MARC::Record framework, and to work on enhancing MARC::Record rather than extending MARC.pm further. Soon afterwards, MARC::Batch was added, which allows you to read in a large data file without having to worry about memory consumption.

In Dec., 2004, the MARC::Lint module, an extension to check the validity of MARC records, was removed from the MARC::Record distribution, to become a separately distributed package. This tutorial contains examples for using MARC::Lint.

Brief Overview of MARC Classes

Here are the packages that get installed with MARC::Record:

MARC::Batch

A convenience class for accessing MARC data contained in an external file.

MARC::Field

An object for representing the indicators and subfields of a single MARC field.

MARC::Record

This primary class represents a MARC record, being a container for multiple MARC::Field objects.

MARC::Doc::Tutorial

This document!

MARC::File

A superclass for representing files of MARC data.

MARC::File::MicroLIF

A subclass of MARC::File for working with data encoded in the MicroLIF format.

MARC::File::USMARC

A subclass of MARC::File for working with data encoded in the USMARC format.

Help Wanted!

Reading a record from a file

   1   ## Example R1
   2
   3   ## create a MARC::Batch object.
   4   use MARC::Batch;
   5   my $batch = MARC::Batch->new('USMARC', 'file.dat');
   6
   7   ## get a MARC record from the MARC::Batch object.
   8   ## the $record will be a MARC::Record object.
   9   my $record = $batch->next();
  10
  11   ## print the title contained in the record.
  12   print $record->title(),"\n";

Using the distribution's 't/camel.usmarc', your result should be:

  ActivePerl with ASP and ADO / Tobias Martinsson.

Iterating through a batch file

   1   ## Example R2
   2
   3   ## create a MARC::Batch object.
   4   use MARC::Batch;
   5   my $batch = MARC::Batch->new('USMARC','file.dat');
   6
   7   while (my $record = $batch->next()) {
   8
   9     ## print the title contained in the record.
  10     print $record->title(),"\n";
  11
  12   }

The call to the "next()" method at line 7 returns the next record from the file. "next()" returns "undef" when there are no more records left in the file, which causes the "while" loop to end. This is a useful idiom for reading in all the records in a file. Your results with 'camel.usmarc' should be:

  ActivePerl with ASP and ADO / Tobias Martinsson.
  Programming the Perl DBI / Alligator Descartes and Tim Bunce.
  .
  .
  .
  Cross-platform Perl / Eric F. Johnson.

Checking for errors

   1   ## Example R3
   2
   3   ## create a MARC::Batch object.
   4   use MARC::Batch;
   5   my $batch = MARC::Batch->new('USMARC','file.dat');
   6
   7   ## get a marc record from the MARC::Batch object.
   8   ## $record will be a MARC::Record object.
   9   while ( my $record = $batch->next() ) {
  10       print $record->title(),"\n";
  11   }
  12
  13   ## make sure there weren't any problems.
  14   if ( my @warnings = $batch->warnings() ) {
  15       print "\nWarnings were detected!\n", @warnings;
  16   }

The call to "warnings()" at line 14 will retrieve any warning messages and store them in @warnings. This allows you to detect when "next()" has aborted prematurely (before the end of the file has been reached). When a warning is detected, an explanation is sent to "STDERR". By introducing an error into 'camel.usmarc', we'll receive the following output to "STDOUT":

  Warnings were detected!
  Invalid indicators "a0" forced to blanks in record 1 for tag 245

Recovering from errors

   1   ## Example R4
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC', 'file.dat');
   5   $batch->strict_off();
   6
   7   while ( my $record = $batch->next() ) {
   8      print $record->title(),"\n";
   9   }
  10
  11   ## make sure there weren't any problems.
  12   if ( my @warnings = $batch->warnings() ) {
  13       print "\nWarnings were detected!\n", @warnings;
  14   }

Introducing a second error to the 'camel.usmarc' file gives the following:

   ActivePerl with ASP and ADO / Tobias Martinsson.
   Programming the Perl DBI / Alligator Descartes and Tim Bunce.
   .
   .
   .
   Cross-platform Perl / Eric F. Johnson.

   Warnings were detected!
   Invalid indicators "a0" forced to blanks in record 1 for tag 245
   Invalid indicators "a0" forced to blanks in record 5 for tag 245

Looking at a field

   1   ## Example R5
   2
   3   ## open a file.
   4   use MARC::Batch;
   5   my $batch = MARC::Batch->new('USMARC','file.dat');
   6
   7   ## read a record.
   8   my $record = $batch->next();
   9
  10   ## get the 100 field as a MARC::Field object.
  11   my $field = $record->field('100');
  12   print "The 100 field contains: ",$field->as_string(),"\n";
  13   print "The 1st indicator is ",$field->indicator(1),"\n";
  14   print "The 2nd indicator is ",$field->indicator(2),"\n";
  15   print "Subfield d contains: ",$field->subfield('d'),"\n";

Which results in something like:

  The 100 field contains: Martinsson, Tobias, 1976-
  The 1st indicator is 1
  The 2nd indicator is
  Subfield d contains: 1976-

As before, use a "while" loop to iterate through all the records in a batch.

Looking at repeatable fields

   1   ## Example R6
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   my $record = $batch->next();
   6
   7   ## get all the 650 fields (list context).
   8   my @fields = $record->field('650');
   9
  10   ## examine each 650 field and print it out.
  11   foreach my $field (@fields) {
  12     print $field->as_string(),"\n";
  13   }

Which prints out the following for the first record of 't/camel.usmarc':

  Active server pages.
  ActiveX.

Looking at a set of related fields

   1   ## Example R7
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   my $record = $batch->next();
   6
   7   # retrieve all title fields in one shot.
   8   foreach my $field ($record->field('2..')) {
   9     print $field->tag(),' contains ',$field->as_string(),"\n";
  10   }

Notice the shorthand in line 8 which compacts lines 7-13 of our previous example. Instead of storing the fields in an array, the "field()" still returns a list in the "for" loop. Line 9 uses the "tag()" method which returns the tag number for a particular MARC field, which is useful when you aren't certain what tag you are currently dealing with. Sample output from this recipe:

   245 contains ActivePerl with ASP and ADO / Tobias Martinsson.
   260 contains New York : John Wiley & Sons, 2000.

You can also return all tags for a specific record by using '...' in "field" (though, see the next recipe).

Looking at all the fields in a record

   1   ## Example R8
   2
   3   use MARC::Batch;
   4   my $file = MARC::Batch->new('USMARC','file.dat');
   5   my $record = $batch->next();
   6
   7   ## get all of the fields using the fields() method.
   8   my @fields = $record->fields();
   9
  10   ## print out the tag, the indicators and the field contents.
  11   foreach my $field (@fields) {
  12     print
  13       $field->tag(), " ",
  14       defined $field->indicator(1) ? $field->indicator(1) : "",
  15       defined $field->indicator(2) ? $field->indicator(2) : "",
  16       " ", $field->as_string, " \n";
  17   }

The above code would print the following for the first record of 't/camel.usmarc':

  001  fol05731351
  003  IMchF
  .
  .
  .
  300    xxi, 289 p. : ill. ; 23 cm. + 1 computer  laser disc (4 3/4 in.)
  500    "Wiley Computer Publishing."
  650  0 Perl (Computer program language)
  630 00 Active server pages.
  630 00 ActiveX.

Creating a record

   1   ## Example C1
   2
   3   ## create a MARC::Record object.
   4   use MARC::Record;
   5   my $record = MARC::Record->new();
   6
   7   ## add the leader to the record. optional.
   8   $record->leader('00903pam  2200265 a 4500');
   9
  10   ## create an author field.
  11   my $author = MARC::Field->new(
  12     '100',1,'',
  13       a => 'Logan, Robert K.',
  14       d => '1939-'
  15     );
  16   $record->append_fields($author);
  17
  18   ## create a title field.
  19   my $title = MARC::Field->new(
  20     '245','1','4',
  21       a => 'The alphabet effect /',
  22       c => 'Robert K. Logan.'
  23     );
  24   $record->append_fields($title);

The key to creating records from scratch is to use "append_fields()", which adds a field to the end of the record. Since each field gets added at the end, it's up to you to order the fields the way you want. "insert_fields_before()" and "insert_fields_after()" are similar methods that allow you to define where the field gets added. These methods are covered in more detail below.

Writing records to a file

   1   ## Example W1
   2
   3   ## create a MARC::Record object.
   4   use MARC::Record;
   5   my $record = MARC::Record->new();
   6
   7   ## add the leader to the record. optional.
   8   $record->leader('00903pam  2200265 a 4500');
   9
  10   ## create an author field.
  11   my $author = MARC::Field->new(
  12     '100',1,'',
  13       a => 'Logan, Robert K.',
  14       d => '1939-'
  15     );
  16
  17   ## create a title field.
  18   my $title = MARC::Field->new(
  19     '245','1','4',
  20       a => 'The alphabet effect /',
  21       c => 'Robert K. Logan.'
  22     );
  23
  24   $record->append_fields($author, $title);
  25
  26   ## open a filehandle to write to 'record.dat'.
  27   open(OUTPUT, '> record.dat') or die $!;
  28   print OUTPUT $record->as_usmarc();
  29   close(OUTPUT);

The "as_usmarc()" method call at line 28 returns a scalar value which is the raw USMARC data for $record. The raw data is then promptly printed to the "OUTPUT" file handle. If you want to output multiple records to a file, simply repeat the process at line 28 for the additional records. Also of note is the "append_fields" method: unlike recipe C1 which called the method once for each field added, this recipe demonstrates that "append_fields" can accept multiple arguments.

Note to the curious: the "as_usmarc()" method is actually an alias to the MARC::File::USMARC "encode()" method. Having separate "encode()" methods is a design feature of the MARC class hierarchy, since it allows extensions to be built that translate MARC::Record objects into different data formats.

Debugging with "as_formatted()"

   1   ## Example W2
   2
   3   ## create a MARC::Record object.
   4   use MARC::Record;
   5   my $record = MARC::Record->new();
   6
   7   $record->leader('00903pam  2200265 a 4500');
   8
   9   $record->append_fields(
  10    MARC::Field->new('100','1','', a=>'Logan, Robert K.', d=>'1939-'),
  11    MARC::Field->new('245','1','4', a=>'The alphabet effect /', c=>'Robert K. Logan.')
  12   );
  13
  14   ## pretty print the record.
  15   print $record->as_formatted(), "\n";

This code will pretty print the contents of the newly created record:

  LDR 00903pam  2200265 a 4500
  100 1  _aLogan, Robert K.
         _d1939-
  245 14 _aThe alphabet effect /
         _cRobert K. Logan.

Notice on lines 9-12 how you can add a list of new fields by creating MARC::Field objects within a call to "append_fields()". This is yet another shorthand method to those shown in recipes C1 and W1. For more pretty-printing capabilities, try "marcdump()" in our next recipe.

Debugging with marcdump()

 % marcdump record.dat
 record.dat
 LDR 00122pam  2200049 a 4500
 100 1  _aLogan, Robert K.
        _d1939-
 245 14 _aThe alphabet effect /
        _cRobert K. Logan.

  Recs  Errs Filename
 ----- ----- --------
     1     0 record.dat

As you can see, this command results in the record being pretty printed to your screen ("STDOUT") similarly to the "as_formatted" method from recipe W2. It is useful for verifying your USMARC data after it has been stored on disk. More details about debugging are found later in VALIDATING.

Adding a field

   1   ## Example U1
   2
   3   ## create our MARC::Batch object.
   4   use MARC::Batch;
   5   my $batch = MARC::Batch->new('USMARC','file.dat');
   6
   7   ## open a file handle to write to.
   8   open(OUT,'>new.dat') or die $!;
   9
  10   ## read each record, modify, then print.
  11   while ( my $record = $batch->next() ) {
  12
  13       ## add a 590 field.
  14       $record->append_fields(
  15          MARC::Field->new('590','','',a=>'Access provided by Enron.')
  16       );
  17
  18       print OUT $record->as_usmarc();
  19
  20   }
  21
  22   close(OUT);

Preserving field order

   1   ## Example U2
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   open(OUT,'>new.dat') or die $!;
   6
   7   ## read in each record.
   8   while ( my $record = $batch->next() ) {
   9
  10       ## find the tag after 590.
  11       my $before;
  12       foreach ($record->fields()) {
  13           $before = $_;
  14           last if $_->tag() > 590;
  15       }
  16
  17       ## create the 590 field.
  18       my $new = MARC::Field->new('590','','',a=>'Access provided by Enron.');
  19
  20       ## insert our 590 field after the $before.
  21       $record->insert_fields_before($before,$new);
  22
  23       ## and print out the new record.
  24       print OUT $record->as_usmarc();
  25
  26   }

Deleting a field

   1   ## Example U3
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','new.dat');
   5   open(OUT,'>newer.dat') or die $1;
   6
   7   while ( my $record = $batch->next() ) {
   8
   9     ## get the 590 record.
  10     my $field = $record->field('590');
  11
  12     ## if there is a 590 AND it has the word "Enron"...
  13     if ($field and $field->as_string() =~ /Enron/i) {
  14
  15       ## delete it!
  16       $record->delete_field($field);
  17
  18     }
  19
  20     ## output possibly modified record.
  21     print OUT $record->as_usmarc();
  22
  23   }

The 590 field is retrieved on line 10, but notice how we check that we actually received a valid $field, and that it then contains the word 'Enron' before we delete it. You need to pass "delete_field()" a MARC::Field object that can be retrieved with the "field()" method.

Changing existing fields

   1   ## Example U4
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','new.dat');
   5   open(OUT,'>newer.dat') or die $1;
   6
   7   while ( my $record = $batch->next() ) {
   8
   9     ## look for a 590 containing "Enron"...
  10     my $field = $record->field('590');
  11     if ($field and $field->as_string =~ /Enron/i) {
  12
  13       ## create a new 590 field.
  14       my $new_field = MARC::Field->new(
  15         '590','','', a => 'Access provided by Arthur Andersen.' );
  16
  17       ## replace existing with our new one.
  18       $field->replace_with($new_field);
  19
  20     }
  21
  22     ## output possibly modified record.
  23     print OUT $record->as_usmarc();
  24
  25   }

In this example, we used MARC::Field's method "replace_with()" to replace an existing field in the record with a new field that we created. To use "replace_with()", you need to retrieve the field you want to replace from a MARC::Record object (line 10), create a new field to replace the existing one with (lines 13-15), and then call the existing field's "replace_with()" method passing the new field as an argument (lines 18). You must pass "replace_with()" a valid MARC::Field object.

Updating subfields and indicators

   1   ## Example U5
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   open(OUT,'>new.dat') or die $!;
   6
   7   while (my $record = $batch->next()) {
   8
   9     ## retrieve the 245 record.
  10     my $field_245 = $record->field('245');
  11
  12     ## if we got 245 and it starts with 'The'...
  13     if ($field_245 and $field_245->as_string() =~ /^The /) {
  14
  15       ## if the 2nd indicator isn't 4, update
  16       if ($field_245->indicator(2) != 4) {
  17         $field_245->update( ind2 => 4 );
  18       }
  19
  20     }
  21
  22     print OUT $record->as_usmarc();
  23
  24   }

In a similar fashion, you can update individual or multiple subfields:

  $field_245->update( a => 'History of the World :', b => 'part 1' );

But beware, you can only update the first occurrence of a subfield using "update()". If you need to do more finer grained updates, you are advised to build a new field and replace the existing field with "replace_with()".

Changing a record's leader

   1   ## Example U6
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   open(OUT,'>new.dat') or die $!;
   6   my $record = $batch->next();
   7
   8   ## get the current leader.
   9   my $leader = $record->leader();
  10
  11   ## replace position 6 with 'm'
  12   substr($leader,6,1) = 'm';
  13
  14   ## update the leader
  15   $record->leader($leader);
  16
  17   ## save the record to a file
  18   print OUT $record->as_usmarc();

Modifying fields without indicators

   1   ## Example U7
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','file.dat');
   5   open(OUT,'>new.dat') or die $!;
   6
   7   while (my $record = $batch->next() ) {
   8
   9     ## see if there is a 005 field.
  10     my $field_005 = $record->field('005');
  11
  12     ## delete it if we find one.
  13     $record->delete_field($field_005) if $field_005;
  14
  15     ## figure out the contents of our new 005 field.
  16     my ($sec,$min,$hour,$mday,$mon,$year) = localtime();
  17     $year += 1900; $mon += 1; # catering to offsets.
  18     my $datetime = sprintf("%4d%02d%02d%02d%02d%02d.0",
  19                             $year,$mon,$mday,$hour,$min,$sec);
  20
  21     ## create a new 005 field using our new datetime.
  22     $record->append_fields( MARC::Field->new('005',$datetime) );
  23
  24     ## save record to a file.
  25     print OUT $record->as_usmarc();
  26
  27   }

Reordering subfields

   1   ## Example U8
   2
   3   use MARC::Batch;
   4   my $batch = MARC::Batch->new('USMARC','856.dat');
   5   open(OUT,'>856_new.dat') or die $!;
   6
   7   while (my $record = $batch->next()) {
   8
   9     my $existing = $record->field('856');
  10
  11     ## make sure 856 exists.
  12     if ($existing) {
  13
  14       ## our ordered subfields.
  15       my @subfields = ();
  16
  17       ## if we have a subfield 3, add it.
  18       if (defined($existing->subfield('3'))) {
  19         push(@subfields,'3',$existing->subfield('3'));
  20       }
  21
  22       ## now add subfields z and u.
  23       push(@subfields,'z','Access restricted',
  24         'u',$existing->subfield('u'));
  25
  26       ## create a new 856.
  27       my $new = MARC::Field->new(
  28          856', $existing->indicator(1),
  29          $existing->indicator(2), @subfields
  30       );
  31
  32       ## replace the existing subfield.
  33       $existing->replace_with($new);
  34
  35     }
  36
  37     ## write out the record
  38     print OUT $record->as_usmarc();
  39
  40   }

Updating subject subfield x to subfield v

   1  ## Example U9
   2
   3  use MARC::Batch;
   4
   5  my $file = shift;
   6
   7  my $batch = MARC::Batch->new('USMARC', $file);
   8  while ( my $record = $batch->next() ) {
   9
  10    # go through all 6XX fields in the record.
  11    foreach my $subject ( $record->field( '6..' ) ) {
  12
  13      # extract subfields as an array of array refs.
  14      my @subfields = $subject->subfields();
  15
  16      # setup an array to store our new field.
  17      my @newSubfields = ();
  18
  19      # a flag to indicate that we found an subfield x.
  20      my $foundX = 0;
  21
  22      # use pop() to read the subfields backwards.
  23      while ( my $subfield = pop( @subfields ) ) {
  24
  25        # for convenience, pull out the subfield
  26        # code and data from  the array ref.
  27        my ($code,$data) = @$subfield;
  28
  29        # if the subfield code is 'x' and
  30        # we haven't already found one...
  31        if ( $code eq 'x' and ! $foundX ) {
  32
  33          # change to a v.
  34          $code = 'v';
  35
  36          # set flag so we know not to
  37          # translate any more subfield x.
  38          $foundX = 1;
  39
  40        }
  41
  42        # add our (potentially changed) subfield
  43        # data to our new subfield data array.
  44        unshift( @newSubfields, $code, $data );
  45
  46      }
  47
  48      # if we did find a subfield x, then create a new field using our
  49      # new subfield data, and replace the old one with the new one.
  50      if ( $foundX ) {
  51        my $newSubject = MARC::Field->new(
  52          $subject->tag(),
  53          $subject->indicator(1),
  54          $subject->indicator(2),
  55          @newSubfields
  56        );
  57        $subject->replace_with( $newSubject );
  58      }
  59
  60    }
  61
  62    # output the potentially changed record as MARC.
  63    print $record->as_usmarc();
  64
  65  }

Using MARC::Lint

   1   ## Example V1
   2
   3   use MARC::Batch;
   4   use MARC::Lint;
   5
   6   my $batch = MARC::Batch->new('USMARC','file.dat');
   7   my $linter = MARC::Lint->new();
   8   my $counter = 0;
   9
  10   while (my $record = $batch->next() ) {
  11
  12     $counter++;
  13
  14     ## feed the record to our linter object.
  15     $linter->check_record($record);
  16
  17     ## get the warnings...
  18     my @warnings = $linter->warnings();
  19
  20     ## output any warnings.
  21     if (@warnings) {
  22
  23       print "RECORD $counter\n";
  24       print join("\n",@warnings),"\n";
  25
  26     }
  27
  28   }

MARC::Lint is quite thorough, and will check the following when validating: presence of a 245 field, repeatability of fields and subfields, valid use of subfield within particular fields, presence of indicators and their values. All checks are based on MARC21 bibliographic format.

Customizing MARC::Lint

MARC::Lint does provide a framework for adding rules. It can be done using the object oriented programming technique of inheritance. In short, you can create your own subclass of MARC::Lint, and then use it to validate your records. Here's an example:

   1   ## Example V2
   2
   3   ## first, create our own subclass of MARC::Lint.
   4   ## should be saved in a file called MyLint.pm.
   5
   6   package MyLint;
   7   use base qw(MARC::Lint);
   8
   9   ## add a method to check that the 856
  10   ## fields contain a correct subfield z.
  11   sub check_856 {
  12
  13     ## your method is passed the MARC::Lint
  14     ## and MARC::Field objects for the record.
  15     my ($self,$field) = @_;
  16
  17     if ($field->subfield('z') ne 'Connect to this resource') {
  18
  19       ## add a warning to our lint object.
  20       $self->warn("856 subfield z must read 'Connect to this resource'.");
  21
  22     }
  23
  24   }

Then create a separate program that uses your subclass to validate your MARC records. You'll need to make sure your program is able to find your module (in this case, MyLint.pm)... this can be achieved by putting both MyLint.pm and the following program in the same directory:

   1   ## Example V3
   2
   3   use MARC::Batch;
   4   use MyLint;
   5
   6   my $linter = MyLint->new();
   7   my $batch = MARC::Batch->new('USMARC','file.marc');
   8   my $counter = 0;
   9
  10   while (my $record = $batch->next()) {
  11
  12     $counter++;
  13
  14     ## check the record
  15     $linter->check_record($record);
  16
  17     ## get the warnings, and print them out
  18     my @warnings = $linter->warnings();
  19     if (@warnings) {
  20       print "RECORD $counter\n";
  21       print join("\n",@warnings),"\n";
  22     }
  23
  24   }

Notice how the call to "check_record()" at line 15 automatically calls the "check_record" in MARC::Lint. The property of inheritance is what makes this happen. $linter is an instance of the MyLint class, and MyLint inherits from the MARC::Lint class, which allows $linter to inherit all the functionality of a normal MARC::Lint object plus the new functionality found in the "check_856" method.

Notice also that we don't have to call "check_856()" directly. The call to "check_record()" automatically looks for any "check_XXX" methods that it can call to verify the record. Pretty neat stuff. If you've added validation checks that you think could be of use to the general public, please share them on the perl4lib mailing list, or become a developer and add them to the source!

Comparing Collections

Authority Records

URLs

ISBN/ISSNs

Call numbers

Subject headings

   1   use MARC::File::USMARC;
   2   use constant MAX => 20;
   3
   4   my %counts;
   5
   6   my $filename = shift or die "Must specify filename\n";
   7   my $file = MARC::File::USMARC->in( $filename );
   8
   9   while ( my $marc = $file->next() ) {
  10       for my $field ( $marc->field("6..") ) {
  11           my $heading = $field->subfield('a');
  12
  13           # trailing whitespace / punctuation.
  14           $heading =~ s/[.,]?\s*$//;
  15
  16           # Now count it.
  17           ++$counts{$heading};
  18       }
  19   }
  20   $file->close();
  21
  22   # Sort the list of headings based on the count of each.
  23   my @headings = reverse sort { $counts{$a} <=> $counts{$b} } keys %counts;
  24
  25   # Take the top N hits...
  26   @headings = @headings[0..MAX-1];
  27
  28   # And print out the results.
  29   for my $heading ( @headings ) {
  30       printf( "%5d %s\n", $counts{$heading}, $heading );
  31   }

Which will generate results like this:

  600 United States
  140 World War, 1939-1945
   78 Great Britain
   63 Afro-Americans
   61 Indians of North America
   58 American poetry
   55 France
   53 West (U.S.)
   53 Science fiction
   53 American literature
   50 Shakespeare, William
   48 Soviet Union
   46 Mystery and detective stories
   45 Presidents
   43 China
   40 Frontier and pioneer life
   38 English poetry
   37 Authors, American
   37 English language
   35 Japan

HTML

XML

MARCMaker

An example of a brief record in this format:

 =LDR  00314nam  22001215a 4500
 =001  ctr00000123\
 =003  XX-XxUND
 =005  20000613133448.0
 =008  051029s2005\\\\xxua\\\\\\\\\\001\0\eng\\
 =040  \\$aXX-XxUND$cXX-XxUND
 =245  00$aSample of MARCMaker record.
 =260  \\$a[United States] :$b[S.n.],$c2005.
 =300  \\$a1 p. ;$c28 cm.

The following example converts an ISO2709 format record into MARCMaker format.

   1    ## Example Maker1
   2
   3    use MARC::Batch;
   4    use MARC::File::MARCMaker;
   5
   6    #mrc indicates ISO2709 format
   7    my $mrc_in = 'in.mrc';
   8    #mrk indicates MARCMaker format
   9    my $mrk_out = 'out.mrk';
   10
   11   #initialize $batch_mrc as new MARC::Batch object
   12   my $batch_mrc = MARC::Batch->new('USMARC', $mrc_in);
   13
   14   #open mrk (MARCMaker) format output file
   15   open (OUTMRK, ">$mrk_out") || die "Cannot open $mrk_out, $!";
   16
   17   my $rec_count = 0;
   18   while (my $record = $batch_mrc->next()) {
   19      $rec_count++;
   20
   21      print OUTMRK MARC::File::MARCMaker->encode($record);
   22
   23   } # while
   24
   25   print "$rec_count records processed\n";

The following example shows conversion from MARCMaker format to ISO2709 format.

   1    ## Example Maker2
   2
   3    use MARC::Batch;
   4    use MARC::File::MARCMaker;
   5
   6    #mrk indicates MARCMaker format
   7    my $mrk_in = 'in.mrk';
   8    #mrc indicates ISO2709 format
   9    my $mrc_out = 'out.mrc';
   10
   11   #initialize $batch_mrk as new MARC::Batch object
   12   my $batch_mrk = MARC::Batch->new( 'MARCMaker', $mrk_in);
   13
   14   #open mrc (ISO2709) format output file
   15   open (OUTMRC, ">$mrc_out") || die "Cannot open $mrc_out, $!";
   16
   17   my $rec_count = 0;
   18   while (my $record = $batch_mrk->next()) {
   19      $rec_count++;
   20
   21      print OUTMRC $record->as_usmarc();
   22
   23   } # while
   24
   25   print "$rec_count records processed\n";

Excel

Z39.50

Chris' program is a command line utility which you run like so:

  ./zm.pl 0596000278

where 0596000278 is an ISBN (for the 3rd edition of the Camel incidentally). The program will query the Library of Congress Z39.50 server for the ISBN, and dump out the retrieved MARC record on the screen. The program is designed to lookup multiple ISBNs if you separate them with a space. This is just an example showing what is possible.

   1   #!/usr/bin/perl -w
   2
   3   # GET-MARC-ISBN -- Get MARC records by ISBN from a Z39.50 server
   4
   5   use strict;
   6   use Carp;
   7   use Net::Z3950;
   8   use MARC::Record;
   9
  10   exit if ($#ARGV < 0);
  11
  12   # We handle multiple ISBNs in the same query by assembling a
  13   # (potentially very large) search string with Prefix Query Notation
  14   # that ORs the ISBN-bearing attributes.
  15   #
  16   # For purposes of automation, we want to request batches of many MARC
  17   # records.  I am not a Z39.50 weenie, though, and I don't know
  18   # offhand if there is a limit on how big a PQN query can be...
  19
  20   my $zq = "\@attr 1=7 ". pop();
  21   while (@ARGV) { $zq = '@or @attr 1=7 '. pop() ." $zq" }
  22
  23   ## HERE IS THE CODE FOR Z3950 REC RETRIEVAL
  24   # Set up connection management structures, connect
  25   # to the server, and submit the Z39.50 query.
  26
  27   my $mgr = Net::Z3950::Manager->new( databaseName => 'voyager' );
  28   $mgr->option( elementSetName => "f" );
  29   $mgr->option( preferredRecordSyntax => Net::Z3950::RecordSyntax::USMARC );
  30
  31   my $conn = $mgr->connect('z3950.loc.gov', '7090');
  32   croak "Unable to connect to server" if !defined($conn);
  33
  34   my $rs = $conn->search($zq);
  35
  36   my $numrec = $rs->size();
  37   print STDERR "$numrec record(s) found\n";
  38
  39   for (my $ii = 1; $ii <= $numrec; $ii++) {
  40
  41       # Extract MARC records from Z3950
  42       # result set, and load MARC::Record.
  43       my $zrec = $rs->record($ii);
  44       my $mrec = MARC::Record->new_from_usmarc($zrec->rawdata());
  45       print $mrec->as_formatted, "\n\n";
  46
  47   }

Databases

 +---------------+---------------+------+-----+---------+----------------+
 | Field         | Type          | Null | Key | Default | Extra          |
 +---------------+---------------+------+-----+---------+----------------+
 | TitleID       | int(7)        |      | PRI | NULL    | auto_increment |
 | RecLastMod    | timestamp(14) | YES  |     | NULL    |                |
 | ISSN          | text          | YES  |     | NULL    |                |
 | RawMARCRecord | blob          | YES  |     | NULL    |                |
 +---------------+---------------+------+-----+---------+----------------+

   1 #!/usr/bin/perl -w
   2
   3 # Script that reads in a file of ISSNs, queries a Z39.50 server,
   4 # and stores resulting records in a database. Limitations: Only
   5 # stores 1 records per ISSN.
   6 # Last updated 2004-09-08 Mark Jordan, mjordan@sfu.ca
   7
   8 use strict;
   9 use Carp;
  10 use Net::Z3950;
  11 use MARC::Record;
  12 use DBI;
  13
  14 # DB connection settings
  15 my $host = "somehost";
  16 my $user = "someuser";
  17 my $password = "somepass";
  18 my $database = "somedb";
  19
  20 # Input file (one ISSS/line)
  21 my $InputFile = $ARGV[0];
  22
  23 # Prepare list of ISSNs to search
  24 my @ISSNs;
  25 open (INPUT, "< $InputFile") or die "Can't find input file\n";
  26 while (<INPUT>) { chomp $_; push (@ISSNs, $_); }
  27 close INPUT;
  28
  29
  30 # Set up connection management structures, connect to the server,
  31 # and submit the Z39.50 query.
  32 my $mgr = Net::Z3950::Manager->new( databaseName => 'voyager' );
  33 $mgr->option( elementSetName => "f" );
  34 $mgr->option( preferredRecordSyntax => Net::Z3950::RecordSyntax::USMARC );
  35 my $conn = $mgr->connect('z3950.loc.gov', '7090');
  36 croak "Unable to connect to server" if !defined($conn);
  37
  38
  39 my $handle = DBI->connect("DBI:mysql:$database:$host","$user","$password")
  40         or die $DBI::errstr;
  41
  42 foreach my $ISSN (@ISSNs) {
  43         my $zq = "\@attr 1=8 ". $ISSN;
  44         my $rs = $conn->search($zq);
  45         my $numrec = $rs->size();
  46         if ($numrec == 0) {
  47             print "Record for ISSN $ISSN not found, moving to next ISSN...\n";
  48             next;
  49         } else {
  50            # Extract MARC record from the result set, and invoke MARC::Record
  51            my $zrec = $rs->record(1);
  52            my $mrec = MARC::Record->new_from_usmarc($zrec->rawdata());
  53            my $rawdata = $zrec->rawdata();
  54            $rawdata = $handle->quote ($rawdata);
  55            # Add to db
  56            my $SQL = "insert into Titles values (NULL,NULL,'$ISSN',$rawdata)";
  57            my $cursor = $handle->prepare($SQL);
  58            $cursor->execute;
  59            print "Record for ISSN $ISSN added to database...\n";
  60            $cursor->finish;
  61         }
  62 }
  63 $handle->disconnect;
  64
  65 __END__

If you want to pull records out of the same database and do something with them, here's a template script:

   1 #!/usr/bin/perl -w
   2
   3 # Script that gets MARC records (in blobs) from a database.
   4 # Last updated 2004-09-08 Mark Jordan, mjordan@sfu.ca
   5
   6 use strict;
   7 use MARC::Record;
   8 use DBI;
   9
  10 # DB connection settings
  11 my $mysql_host = "somehost";
  12 my $mysql_user = "someuser";
  13 my $mysql_password = "somepass*";
  14 my $mysql_database = "somedb";
  15
  16
  17 my $handle = DBI->connect("DBI:mysql:$mysql_database:$mysql_host",
  18         "$mysql_user","$mysql_password") or die $DBI::errstr;
  19
  20 my $SQL = "select * from Titles";
  21 my $cursor = $handle->prepare($SQL);
  22 $cursor->execute;
  23
  24 while (my @Records = $cursor->fetchrow_array) {
  25         my $RawMARC = $Records[3];
  26         my $mrec = MARC::Record->new_from_usmarc($RawMARC);
  27         # Print out the title
  28         print $mrec->title , "\n";
  29 }
  30
  31 $cursor->finish;
  32 $handle->disconnect;
  33
  34 __END__

Procite/Endnote