NAME

       MARC::Schema - Specification of the MARC21 format

SYNOPSIS

           # in Perl
           use MARC::Schema;

           my $record = {
               _id    => 'fol05865967',
               record => [
                   [ 'LDR', undef, undef, '_', '00661nam  22002538a 4500' ],
                   [ '001', undef, undef, '_', 'fol05865967' ],
                   [ '001', undef, undef, '_', 'field is not repeatable' ],
                   [   '245', '1', '0', 'a', 'Programming Perl /',
                       'c', 'Larry Wall, Tom Christiansen & Jon Orwant.',
                       'a', 'subfield is not repeatable',
                       'x', 'unknown subfield',
                   ],
                   [ '999', undef, undef, '_', 'not a standard field']
               ]
           };

           # load default schema
           my $schema = MARC::Schema->new();

           # load custom schema from file
           my $schema = MARC::Schema->new({ file => share/marc-schema.json });

           # load custom schema
           my $schema = MARC::Schema->new(
               {   fields => {
                       '001' => { label => 'Control Number', repetable => 0 }
                   }
               }
           );
           my @check = $schema->check($record);

           # via the command line
           $ marcvalidate t/camel.mrc
           $ marcvalidate --schema marc_schema.json t/camel.mrc
           $ marcvalidate --type XML marc.xml

DESCRIPTION

       MARC::Schema defines a set of MARC21 fields and subfields to validate Catmandu::MARC
       records. A schema is given as hash reference such as:

           {   fields => {
                   LDR => {
                       positions =>
                           [ { position => '00-04', label => 'Record length' } ],
                       repeatable => 0,
                   },
                   '001' => { label => 'Control Number', repeatable => 0 }
               }
           }

       For a more detailed description of the (default) schema see MARC21 structure in JSON
       <https://pkiraly.github.io/2018/01/28/marc21-in-json/>.

METHODS

   check( $record [, %options ] )
       Check whether a given "Catmandu::Importer::MARC" or "MARC::Parser::*"
       <https://metacpan.org/search?q=%22MARC%3A%3AParser%22> record confirms to the schema and
       return a list of detected violations. Possible options include:

       ignore_unknown_fields
           Don't report fields not included in the schema.

       ignore_unknown_subfields
           Don't report subfields not included in the schema.

       Errors are given as list of hash references with keys "error", "tag", "type" and "value"
       of the violated field. "error" contains a human-readable error message for each violated
       field and/or subfield.

   check_field( $field [, %options ] )
       Check whether a MARC21 field confirms to the schema. Use same options as method "check".

AUTHOR

       Johann Rolschewski <jorol@cpan.org>

CONTRIBUTORS

       Patrick Hochstenbach <patrick.hochstenbach@ugent.be<gt>

COPYRIGHT

       Copyright 2018- Johann Rolschewski

LICENSE

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

SEE ALSO

       Catmandu::Validator

       JSON::Schema

       PICA::Schema

       MARC::Lint

ACKNOWLEDGEMENT

       MARC::Schema uses the MARC21 schema developed by PXter KirXly <https://github.com/pkiraly>
       as default. For more information see "Metadata assessment for MARC records"
       <https://github.com/pkiraly/metadata-qa-marc> and "MARC21 structure in JSON"
       <https://pkiraly.github.io/2018/01/28/marc21-in-json/>.