--- /dev/null
+CREATE OR REPLACE FUNCTION evergreen.maintain_901 () RETURNS TRIGGER AS $func$
+use strict;
+use MARC::Record;
+use MARC::File::XML (BinaryEncoding => 'UTF-8');
+use MARC::Charset;
+use Encode;
+use Unicode::Normalize;
+
+MARC::Charset->assume_unicode(1);
+
+my $schema = $_TD->{table_schema};
+my $marc = MARC::Record->new_from_xml($_TD->{new}{marc});
+
+my @old901s = $marc->field('901');
+$marc->delete_fields(@old901s);
+
+if ($schema eq 'biblio') {
+ my $tcn_value = $_TD->{new}{tcn_value};
+
+ # Set TCN value to record ID?
+ my $id_as_tcn = spi_exec_query("
+ SELECT enabled
+ FROM config.global_flag
+ WHERE name = 'cat.bib.use_id_for_tcn'
+ ");
+ if (($id_as_tcn->{processed}) && $id_as_tcn->{rows}[0]->{enabled} eq 't') {
+ $tcn_value = $_TD->{new}{id};
+ $_TD->{new}{tcn_value} = $tcn_value;
+ }
+
+ my $new_901 = MARC::Field->new("901", " ", " ",
+ "a" => $tcn_value,
+ "b" => $_TD->{new}{tcn_source},
+ "c" => $_TD->{new}{id},
+ "t" => $schema
+ );
+
+ if ($_TD->{new}{owner}) {
+ $new_901->add_subfields("o" => $_TD->{new}{owner});
+ }
+
+ if ($_TD->{new}{share_depth}) {
+ $new_901->add_subfields("d" => $_TD->{new}{share_depth});
+ }
+
+ $marc->append_fields($new_901);
+} elsif ($schema eq 'authority') {
+ my $new_901 = MARC::Field->new("901", " ", " ",
+ "c" => $_TD->{new}{id},
+ "t" => $schema,
+ );
+ $marc->append_fields($new_901);
+} elsif ($schema eq 'serial') {
+ my $new_901 = MARC::Field->new("901", " ", " ",
+ "c" => $_TD->{new}{id},
+ "t" => $schema,
+ "o" => $_TD->{new}{owning_lib},
+ );
+
+ if ($_TD->{new}{record}) {
+ $new_901->add_subfields("r" => $_TD->{new}{record});
+ }
+
+ $marc->append_fields($new_901);
+} else {
+ my $new_901 = MARC::Field->new("901", " ", " ",
+ "c" => $_TD->{new}{id},
+ "t" => $schema,
+ );
+ $marc->append_fields($new_901);
+}
+
+my $xml = $marc->as_xml_record();
+$xml =~ s/\n//sgo;
+$xml =~ s/^<\?xml.+\?\s*>//go;
+$xml =~ s/>\s+</></go;
+$xml =~ s/\p{Cc}//go;
+
+# Embed a version of OpenILS::Application::AppUtils->entityize()
+# to avoid having to set PERL5LIB for PostgreSQL as well
+
+# If we are going to convert non-ASCII characters to XML entities,
+# we had better be dealing with a UTF8 string to begin with
+$xml = decode_utf8($xml);
+
+$xml = NFC($xml);
+
+# Convert raw ampersands to entities
+$xml =~ s/&(?!\S+;)/&/gso;
+
+# Convert Unicode characters to entities
+$xml =~ s/([\x{0080}-\x{fffd}])/sprintf('&#x%X;',ord($1))/sgoe;
+
+$xml =~ s/[\x00-\x1f]//go;
+$_TD->{new}{marc} = $xml;
+
+return "MODIFY";
+$func$ LANGUAGE PLPERLU;