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 --file t/camel.mrc --type RAW

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 reference with keys label, message,
    repeatable, subfields and tag of the violated field. If key subfields
    is set, the field contained invalid subfields. The error field message
    contains a human-readable error message which 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 Péter Király
    <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/>.