/usr/share/perl5/RDF/Query/Compiler/SQL.pm is in librdf-query-perl 2.918-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 | # RDF::Query::Compiler::SQL
# -----------------------------------------------------------------------------
=head1 NAME
RDF::Query::Compiler::SQL - Compile a SPARQL query directly to SQL.
=head1 VERSION
This document describes RDF::Query::Compiler::SQL version 2.918.
=head1 STATUS
This module's API and functionality should be considered deprecated.
If you need functionality that this module provides,
please L<get in touch|http://www.perlrdf.org/>.
=cut
package RDF::Query::Compiler::SQL;
use strict;
use warnings;
no warnings 'redefine';
use RDF::Query::Error qw(:try);
use Log::Log4perl;
use List::Util qw(first);
use Data::Dumper;
use Math::BigInt;
use Digest::MD5 ('md5');
#use Digest::Perl::MD5 (); #('md5');
use Carp qw(carp croak confess);
use Scalar::Util qw(blessed reftype);
use RDF::Query::Error qw(:try);
######################################################################
my (@NODE_TYPE_TABLES, %NODE_TYPE_TABLES);
our ($VERSION);
BEGIN {
$VERSION = '2.918';
@NODE_TYPE_TABLES = (
['Resources', 'ljr', 'URI'],
['Literals', 'ljl', qw(Value Language Datatype)],
['Bnodes', 'ljb', qw(Name)]
);
%NODE_TYPE_TABLES = map { $_->[0] => [ @{ $_ }[1 .. $#{ $_ }] ] } @NODE_TYPE_TABLES;
}
######################################################################
use constant INDENT => "\t";
=head1 METHODS
=over 4
=cut
=item C<< new ( $parse_tree ) >>
Returns a new compiler object.
=cut
sub new {
my $class = shift;
my $parsed = shift;
my $model = shift;
my $l = Log::Log4perl->get_logger("rdf.query.compiler.sql");
my $stable;
if ($model) {
my $mhash = _mysql_hash( $model );
$l->debug("Model: $model => $mhash\n");
$stable = "Statements${mhash}";
} else {
$stable = 'Statements';
}
my $self = bless( {
parsed => $parsed,
stable => $stable,
vars => {},
from => [],
where => [],
}, $class );
return $self;
}
=item C<< compile () >>
Returns a SQL query string for the specified parse tree.
=cut
sub compile {
my $self = shift;
my $parsed = $self->{parsed};
my $sql;
try {
my $method = uc $parsed->{'method'};
if ($method eq 'SELECT') {
$sql = $self->emit_select();
} else {
throw RDF::Query::Error::CompilationError( -text => "SQL compilation of $method queries not yet implemented." );
}
} catch RDF::Query::Error::CompilationError with {
my $err = shift;
throw $err;
};
return $sql;
}
=item C<< emit_select >>
Returns a SQL query string representing the query.
=cut
sub emit_select {
my $self = shift;
my $parsed = $self->{parsed};
my $level = \do { my $a = 0 };
my @vars = map { $_->name } @{ $parsed->{variables} };
my %select_vars = map { $_ => 1 } @vars;
$self->patterns2sql( $parsed->{'triples'}, $level );
my ($varcols, @cols) = $self->add_variable_values_joins;
my $vars = $self->{vars};
my $from = $self->{from};
my $where = $self->{where};
my $options = $self->{options} || {};
my $unique = $options->{'distinct'};
my $from_clause;
foreach my $f (@$from) {
$from_clause .= ",\n" . INDENT if ($from_clause and $from_clause =~ m/[^(]$/ and $f !~ m/^([)]|LEFT JOIN)/);
$from_clause .= $f;
}
my $where_clause = @$where ? "WHERE\n"
. INDENT . join(" AND\n" . INDENT, @$where) : '';
my @sql = (
"SELECT" . ($unique ? ' DISTINCT' : ''),
INDENT . join(",\n" . INDENT, @cols),
"FROM",
INDENT . $from_clause,
$where_clause,
);
push(@sql, $self->order_by_clause( $varcols, $level ) );
push(@sql, $self->limit_clause( $options ) );
my $sql = join("\n", grep {length} @sql);
return $sql;
}
=item C<< limit_clause >>
Returns a SQL LIMIT clause, or an empty string if the query does not need limiting.
=cut
sub limit_clause {
my $self = shift;
my $options = shift;
if (my $limit = $options->{limit}) {
return "LIMIT ${limit}";
} else {
return "";
}
}
=item C<< order_by_clause >>
Returns a SQL ORDER BY clause, or an empty string if the query does not use ordering.
=cut
sub order_by_clause {
my $self = shift;
my $varcols = shift;
my $level = shift || \do{ my $a = 0 };
my $vars = $self->{vars};
my $options = $self->{options} || {};
my %variable_value_cols = %$varcols;
my $sql = '';
if ($options->{orderby}) {
my $data = $options->{orderby}[0];
my ($dir, @operands) = @$data;
if (scalar(@operands) > 1) {
throw RDF::Query::Error::CompilationError( -text => "Can't sort by more than one column yet." );
}
my $sort = $operands[0];
if (blessed($sort) and $sort->type eq 'VAR') {
my $var = $sort->name;
my @cols = $self->variable_columns( $var );
$sql .= "ORDER BY\n"
. INDENT . join(', ', map { "$_ $dir" } @cols );
} elsif (blessed($sort) and $sort->type eq 'FUNCTION') {
my $uri = $self->qualify_uri( $sort->uri );
my $col = $self->expr2sql( $sort, $level );
my @sort;
foreach my $var (keys %$vars) {
my ($l_sort_col, $r_sort_col, $b_sort_col) = @{ $variable_value_cols{ $var } };
my $varcol = $vars->{ $var };
if ($col =~ /${varcol}/) {
my ($l, $r, $b) = ($col) x 3;
$l =~ s/$varcol/${l_sort_col}/;
$r =~ s/$varcol/${r_sort_col}/;
$b =~ s/$varcol/${b_sort_col}/;
push(@sort, "$l $dir, $r $dir, $b $dir");
last;
}
}
unless (@sort) {
push(@sort, "${col} $dir");
}
$sql .= "ORDER BY\n"
. INDENT . join(', ', @sort);
} else {
throw RDF::Query::Error::CompilationError( -text => "Can't sort by $$data[1][0] yet." );
}
}
return $sql;
}
=item C<< variable_columns ( $var ) >>
Given a variable name, returns the set of column aliases that store the values
for the column (values for Literals, URIs, and Blank Nodes).
=cut
sub variable_columns {
my $self = shift;
my $var = shift;
return map { "${var}_$_" } (qw(Value URI Name));
}
=item C<< add_variable_values_joins >>
Modifies the query by adding LEFT JOINs to the tables in the database that
contain the node values (for literals, resources, and blank nodes).
=cut
sub add_variable_values_joins {
my $self = shift;
my $l = Log::Log4perl->get_logger("rdf.query.algebra.service");
my $parsed = $self->{parsed};
my @vars = map { $_->name } @{ $parsed->{variables} };
my %select_vars = map { $_ => 1 } @vars;
my %variable_value_cols;
my $vars = $self->{vars};
my $from = $self->{from};
my $where = $self->{where};
my @cols;
my $uniq_count = 0;
my (%seen_vars, %seen_joins);
foreach my $var (grep { not $seen_vars{ $_ }++ } (@vars, keys %$vars)) {
my $col = $vars->{ $var };
unless ($col) {
throw RDF::Query::Error::CompilationError "*** Nothing is known about the variable ?${var}";
}
my $col_table = (split(/[.]/, $col))[0];
my ($count) = ($col_table =~ /\w(\d+)/);
$l->debug("var: $var\t\tcol: $col\t\tcount: $count\t\tunique count: $uniq_count\n");
push(@cols, "${col} AS ${var}_Node") if ($select_vars{ $var });
foreach (@NODE_TYPE_TABLES) {
my ($table, $alias, @join_cols) = @$_;
foreach my $jc (@join_cols) {
my $column_real_name = "${alias}${uniq_count}.${jc}";
my $column_alias_name = "${var}_${jc}";
push(@cols, "${column_real_name} AS ${column_alias_name}");
push( @{ $variable_value_cols{ $var } }, $column_real_name);
foreach my $i (0 .. $#{ $where }) {
if ($where->[$i] =~ /\b$column_alias_name\b/) {
$where->[$i] =~ s/\b${column_alias_name}\b/${column_real_name}/g;
}
}
}
}
foreach my $i (0 .. $#{ $from }) {
my $f = $from->[ $i ];
next if ($from->[ $i ] =~ m/^[()]$/);
my ($alias) = ($f =~ m/Statements\d* (\w\d+)/); #split(/ /, $f))[1];
if ($alias eq $col_table) {
# my (@tables, @where);
foreach (@NODE_TYPE_TABLES) {
my ($vtable, $vname) = @$_;
my $valias = join('', $vname, $uniq_count);
next if ($seen_joins{ $valias }++);
# push(@tables, "${vtable} ${valias}");
# push(@where, "${col} = ${valias}.ID");
$f .= " LEFT JOIN ${vtable} ${valias} ON (${col} = ${valias}.ID)";
}
# my $join = sprintf("LEFT JOIN (%s) ON (%s)", join(', ', @tables), join(' AND ', @where));
# $from->[ $i ] = join(' ', $f, $join);
$from->[ $i ] = $f;
next;
}
}
$uniq_count++;
}
return (\%variable_value_cols, @cols);
}
=item C<< patterns2sql ( \@triples, \$level, %args ) >>
Builds the SQL query in instance data from the supplied C<@triples>.
C<$level> is used as a unique identifier for recursive calls.
C<%args> may contain callback closures for the following keys:
'where_hook'
'from_hook'
When present, these closures are used to add SQL FROM and WHERE clauses
to the query instead of adding them directly to the object's instance data.
=cut
sub patterns2sql {
my $self = shift;
my $triples = shift;
my $level = shift || \do{ my $a = 0 };
my %args = @_;
# my %vars = scalar(@_) ? %{ $_[0] } : ();
my $parsed = $self->{parsed};
my $parsed_vars = $parsed->{variables};
my %queryvars = map { $_->name => 1 } @$parsed_vars;
# my (@from, @where);
my $from = $self->{from};
my $where = $self->{where};
my $vars = $self->{vars};
my $add_where = sub {
my $w = shift;
if (my $hook = $args{ where_hook }) {
push(@$where, $hook->( $w ));
} else {
push(@$where, $w);
}
return $w;
};
my $add_from = sub {
my $f = shift;
if (my $hook = $args{ from_hook }) {
push(@$from, $hook->( $f ));
} else {
push(@$from, $f);
}
return $f;
};
my $triple = shift(@$triples);
Carp::confess "unblessed atom: " . Dumper($triple) unless (blessed($triple));
if ($triple->isa('RDF::Query::Algebra::Triple') or $triple->isa('RDF::Query::Algebra::Quad')) {
my $quad = $triple->isa('RDF::Query::Algebra::Quad');
my @posmap = ($quad)
? qw(subject predicate object context)
: qw(subject predicate object);
# $add_from->('(');
my $table = "s${$level}";
my $stable = $self->{stable};
$add_from->( "${stable} ${table}" );
foreach my $method (@posmap) {
my $node = $triple->$method();
my $pos = $method;
my $col = "${table}.${pos}";
if ($node->isa('RDF::Query::Node::Variable')) {
my $name = $node->name;
if (exists $vars->{ $name }) {
my $existing_col = $vars->{ $name };
$add_where->( "$col = ${existing_col}" );
} else {
$vars->{ $name } = $col;
}
} elsif ($node->isa('RDF::Query::Node::Resource')) {
my $uri = $node->uri_value;
my $id = $self->_mysql_node_hash( $node );
$id =~ s/\D//;
$add_where->( "${col} = $id" );
} elsif ($node->isa('RDF::Query::Node::Blank')) {
my $id = $node->blank_identifier;
my $b = "b${$level}";
$add_from->( "Bnodes $b" );
$add_where->( "${col} = ${b}.ID" );
$add_where->( "${b}.Name = '$id'" );
} elsif ($node->isa('RDF::Query::Node::Literal')) {
my $id = $self->_mysql_node_hash( $node );
$id =~ s/\D//;
$add_where->( "${col} = $id" );
} else {
throw RDF::Query::Error::CompilationError( -text => "Unknown node type: " . Dumper($node) );
}
}
# $add_from->(')');
} else {
if ($triple->isa('RDF::Query::Algebra::Optional')) {
throw RDF::Query::Error::CompilationError( -text => "SQL compilation of OPTIONAL blocks is currently broken" );
} elsif ($triple->isa('RDF::Query::Algebra::NamedGraph')) {
$self->patterns2sql( [ $triple->pattern ], $level, %args );
# my $graph = $triple->graph;
# my $pattern = $triple->pattern;
# if ($graph->isa('RDF::Query::Node::Variable')) {
# my $name = $graph->name;
# my $context;
# my $hook = sub {
# my $f = shift;
# if ($f =~ /^Statements/i) {
# my $alias = (split(/ /, $f))[1];
# if (defined($context)) {
# $context =~ s/\D//;
# $add_where->( "${alias}.Context = ${context}" );
# } else {
# $context = "${alias}.Context";
# $vars->{ $name } = $context;
# }
# }
# return $f;
# };
# $self->patterns2sql( [ $pattern ], $level, from_hook => $hook );
# } else {
# my $hash = $self->_mysql_node_hash( $graph );
# my $hook = sub {
# my $f = shift;
# if ($f =~ /^Statements/i) {
# my $alias = (split(/ /, $f))[1];
# $hash =~ s/\D//;
# $add_where->( "${alias}.Context = ${hash}" );
# }
# return $f;
# };
# $self->patterns2sql( [ $pattern ], $level, from_hook => $hook );
# }
} elsif ($triple->isa('RDF::Query::Algebra::Filter')) {
++$$level;
my $expr = $triple->expr;
my $pattern = $triple->pattern;
$self->expr2sql( $expr, $level, from_hook => $add_from, where_hook => $add_where );
++$$level;
$self->patterns2sql( [ $pattern ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::BasicGraphPattern')) {
++$$level;
$self->patterns2sql( [ $triple->triples ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::GroupGraphPattern')) {
++$$level;
$self->patterns2sql( [ $triple->patterns ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::Distinct')) {
$self->{options}{distinct} = 1;
my $pattern = $triple->pattern;
$self->patterns2sql( [ $pattern ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::Limit')) {
$self->{options}{limit} = $triple->limit;
my $pattern = $triple->pattern;
$self->patterns2sql( [ $pattern ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::Offset')) {
$self->{options}{offset} = $triple->offset;
my $pattern = $triple->pattern;
$self->patterns2sql( [ $pattern ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::Sort')) {
$self->{options}{orderby} = [ $triple->orderby ];
my $pattern = $triple->pattern;
$self->patterns2sql( [ $pattern ], $level, %args );
} elsif ($triple->isa('RDF::Query::Algebra::Project')) {
my $pattern = $triple->pattern;
$self->patterns2sql( [ $pattern ], $level, %args );
} else {
throw RDF::Query::Error::CompilationError( -text => "Unknown pattern type '$triple' in SQL compilation." );
}
}
if (scalar(@$triples)) {
++$$level;
$self->patterns2sql( $triples, $level );
}
return;
# return (\%vars, \@from, \@where);
}
=item C<< expr2sql ( $expression, \$level, %args ) >>
Returns a SQL expression for the supplied query C<$expression>.
C<$level> is used as a unique identifier for recursive calls.
C<%args> may contain callback closures for the following keys:
'where_hook'
'from_hook'
When present, these closures are used to add necessary SQL FROM and WHERE
clauses to the query.
=cut
sub expr2sql {
my $self = shift;
my $expr = shift;
my $level = shift || \do{ my $a = 0 };
my %args = @_;
my $equality = do { no warnings 'uninitialized'; ($args{'equality'} eq 'rdf') ? 'rdf' : 'xpath' };
my $from = $self->{from};
my $where = $self->{where};
my $vars = $self->{vars};
my $sql;
my $add_where = sub {
my $w = shift;
$sql ||= $w;
if (my $hook = $args{ where_hook }) {
$hook->( $w );
}
};
my $add_from = sub {
my $f = shift;
if (my $hook = $args{ from_hook }) {
$hook->( $f );
}
};
my $parsed = $self->{parsed};
my $parsed_vars = $parsed->{variables};
my %queryvars = map { $_->name => 1 } @$parsed_vars;
Carp::confess unless ref($expr);
my $blessed = blessed($expr);
if ($blessed and $expr->isa('RDF::Trine::Node')) {
if ($expr->isa('RDF::Trine::Node::Literal')) {
my $literal = $expr->literal_value;
my $dt = $expr->literal_datatype;
my $hash = $self->_mysql_node_hash( $expr );
if ($equality eq 'rdf') {
$literal = $hash;
} else {
if (defined($dt)) {
my $uri = $dt;
my $func = $self->get_function( $self->qualify_uri( $uri ) );
if ($func) {
my ($v, $f, $w) = $func->( $self, $parsed_vars, $level, RDF::Query::Node::Literal->new($literal) );
$literal = $w->[0];
} else {
$literal = qq("${literal}");
}
} else {
$literal = qq('${literal}');
}
}
$add_where->( $literal );
} elsif ($expr->isa('RDF::Query::Node::Blank')) {
my $hash = $self->_mysql_node_hash( $expr );
$add_where->( $hash );
} elsif ($expr->isa('RDF::Query::Node::Resource')) {
my $uri = $self->_mysql_node_hash( $expr );
$add_where->( $uri );
} elsif ($expr->isa('RDF::Query::Node::Variable')) {
my $name = $expr->name;
my $col = $vars->{ $name };
no warnings 'uninitialized';
$add_where->( qq(${col}) );
}
} elsif ($blessed and $expr->isa('RDF::Query::Expression::Function')) {
my $uri = $expr->uri->uri_value;
my $func = $self->get_function( $uri );
if ($func) {
my ($v, $f, $w) = $func->( $self, $parsed_vars, $level, $expr->arguments );
foreach my $key (keys %$v) {
my $val = $v->{ $key };
$vars->{ $key } = $val unless (exists($vars->{ $key }));
}
foreach my $f (@$f) {
$add_from->( @$f );
}
foreach my $w (@$w) {
$add_where->( $w );
}
} else {
throw RDF::Query::Error::CompilationError( -text => "Unknown custom function $uri in FILTER." );
}
} elsif ($blessed and $expr->isa('RDF::Query::Expression')) {
my $op = $expr->op;
my @args = $expr->operands;
if ($op eq '!') {
if ($args[0]->isa('RDF::Query::Expression::Function')) {
if ($args[0]->uri->uri_value eq 'sparql:isbound') {
my $expr = RDF::Query::Expression::Function->new(
RDF::Query::Node::Resource->new('rdfquery:isNotBound'),
$args[0]->arguments
);
$self->expr2sql( $expr, $level, %args );
}
}
} else {
if ($op =~ m#^(=|==|!=|[<>]=?|[*]|/|[-+])$#) {
$op = '<>' if ($op eq '!=');
$op = '=' if ($op eq '==');
my ($a, $b) = @args;
my $a_type = $a->type;
my $b_type = $b->type;
try {
if ($op eq '=') {
if ($a_type eq 'VAR' and $b_type eq 'VAR') {
# comparing equality on two type-unknown variables.
# could need rdf-term equality, so punt to the
# catch block below.
throw RDF::Query::Error::ComparisonError;
}
}
foreach my $data ([$a_type, 'LHS'], [$b_type, 'RHS']) {
my ($type, $side) = @$data;
unless ($type =~ m/^(VAR|LITERAL|FUNCTION)$/) {
if ($op =~ m/^!?=$/) {
# throw to the catch block below.
throw RDF::Query::Error::ComparisonError( -text => "Using comparison operator '${op}' on unknown node type requires RDF-Term semantics." );
} else {
# throw error out of the compiler.
throw RDF::Query::Error::CompilationError( -text => "Cannot use the comparison operator '${op}' on a ${side} ${type} node." );
}
}
}
if ($a_type eq 'VAR') {
++$$level; my $var_name_a = $self->expr2sql( $a, $level, equality => $equality );
my $sql_a = "(SELECT value FROM Literals WHERE ${var_name_a} = ID LIMIT 1)";
if ($b_type eq 'VAR') {
# ?var cmp ?var
++$$level; my $var_name_b = $self->expr2sql( $b, $level, equality => $equality );
my $sql_b = "(SELECT value FROM Literals WHERE ${var_name_b} = ID LIMIT 1)";
$add_where->( "${sql_a} ${op} ${sql_b}" );
} else {
# ?var cmp NODE
++$$level; my $sql_b = $self->expr2sql( $b, $level, equality => $equality );
$add_where->( "${sql_a} ${op} ${sql_b}" );
}
} else {
++$$level; my $sql_a = $self->expr2sql( $a, $level, equality => $equality );
if ($b->type eq 'VAR') {
# ?var cmp NODE
++$$level; my $var_name = $self->expr2sql( $b, $level, equality => $equality );
my $sql_b = "(SELECT value FROM Literals WHERE ${var_name} = ID LIMIT 1)";
$add_where->( "${sql_a} ${op} ${sql_b}" );
} else {
# NODE cmp NODE
++$$level; my $sql_b = $self->expr2sql( $b, $level, equality => $equality );
$add_where->( "${sql_a} ${op} ${sql_b}" );
}
}
} catch RDF::Query::Error::ComparisonError with {
# we can't compare these terms using the XPath semantics (for literals),
# so fall back on RDF-Term semantics.
my $err = shift;
my @w;
my $where_hook = sub {
my $w = shift;
push(@w, $w);
return;
};
foreach my $expr (@args) {
$self->expr2sql( $expr, $level, %args, %args, equality => 'rdf', where_hook => $where_hook )
}
$add_where->("$w[0] ${op} $w[1]");
};
} elsif ($op eq '&&') {
foreach my $expr (@args) {
$self->expr2sql( $expr, $level, %args )
}
} elsif ($op eq '||') {
my @w;
my $where_hook = sub {
my $w = shift;
push(@w, $w);
return;
};
foreach my $expr (@args) {
$self->expr2sql( $expr, $level, %args, where_hook => $where_hook )
}
my $where = '(' . join(' OR ', map { qq<($_)> } @w) . ')';
$add_where->( $where );
} else {
throw RDF::Query::Error::CompilationError( -text => "SQL compilation of FILTER($op) queries not yet implemented." );
}
}
}
return $sql;
}
=item C<< _mysql_hash ( $data ) >>
Returns a hash value for the supplied C<$data> string. This value is computed
using the same algorithm that Redland's mysql storage backend uses.
=cut
sub _mysql_hash {
my $data = shift;
my @data = unpack('C*', md5( $data ));
my $sum = Math::BigInt->new('0');
# my $count = 0;
foreach my $count (0 .. 7) {
# while (@data) {
my $data = Math::BigInt->new( $data[ $count ] ); #shift(@data);
my $part = $data << (8 * $count);
# warn "+ $part\n";
$sum += $part;
} # continue { last if ++$count == 8 } # limit to 64 bits
# warn "= $sum\n";
$sum =~ s/\D//; # get rid of the extraneous '+' that pops up under perl 5.6
return $sum;
}
=item C<< _mysql_node_hash ( $node ) >>
Returns a hash value (computed by C<_mysql_hash> for the supplied C<$node>.
The hash value is based on the string value of the node and the node type.
=cut
sub _mysql_node_hash {
my $self = shift;
my $node = shift;
# my @node = @$node;
# my ($type, $value) = splice(@node, 0, 2, ());
my $data;
Carp::confess 'node a blessed node: ' . Dumper($node) unless blessed($node);
if ($node->isa('RDF::Query::Node::Resource')) {
my $value = $node->uri_value;
if (ref($value)) {
$value = $self->qualify_uri( $value );
}
$data = 'R' . $value;
} elsif ($node->isa('RDF::Query::Node::Blank')) {
my $value = $node->blank_identifier;
$data = 'B' . $value;
} elsif ($node->isa('RDF::Query::Node::Literal')) {
my $value = $node->literal_value;
my $lang = $node->literal_value_language;
my $dt = $node->literal_datatype;
no warnings 'uninitialized';
$data = sprintf("L%s<%s>%s", $value, $lang, $dt);
# warn "($data)";
} else {
return undef;
}
my $hash = _mysql_hash( $data );
return $hash;
}
=item C<< qualify_uri ( $uri ) >>
Returns a fully qualified URI from the supplied C<$uri>. C<$uri> may already
be a qualified URI, or a parse tree for a qualified URI or QName. If C<$uri> is
a QName, the namespaces defined in the query parse tree are used to fully qualify.
=cut
sub qualify_uri {
my $self = shift;
my $uri = shift;
my $parsed = $self->{parsed};
if (ref($uri) and $uri->type eq 'URI') {
$uri = $uri->uri_value;
}
if (ref($uri)) {
my ($abbr, $local) = @$uri;
if (exists $parsed->{namespaces}{$abbr}) {
my $ns = $parsed->{namespaces}{$abbr};
$uri = join('', $ns, $local);
} else {
throw RDF::Query::Error::ParseError ( -text => "Unknown namespace prefix: $abbr" );
}
}
return $uri;
}
=item C<add_function ( $uri, $function )>
Associates the custom function C<$function> (a CODE reference) with the
specified URI, allowing the function to be called by query FILTERs.
=cut
sub add_function {
my $self = shift;
my $uri = shift;
my $code = shift;
if (ref($self)) {
$self->{'functions'}{$uri} = $code;
} else {
our %functions;
$functions{ $uri } = $code;
}
}
=item C<get_function ( $uri )>
If C<$uri> is associated with a query function, returns a CODE reference
to the function. Otherwise returns C<undef>.
=cut
sub get_function {
my $self = shift;
my $uri = shift;
our %functions;
my $func = $self->{'functions'}{$uri} || $functions{ $uri };
return $func;
}
our %functions;
BEGIN {
$functions{ 'sparql:regex' } = sub {
my $self = shift;
my $parsed_vars = shift;
my $level = shift || \do{ my $a = 0 };
my @args = @_;
my (@from, @where);
my (@regex, @literal, @pattern);
if (blessed($args[0]) and $args[0]->isa('RDF::Query::Node::Variable')) {
my $name = $args[0]->name;
push(@literal, "${name}_Value");
push(@literal, "${name}_URI");
push(@literal, "${name}_Name");
} else {
push(@literal, $self->expr2sql( $args[0], $level ));
}
if ($args[1]->type eq 'VAR') {
my $name = $args[0][1];
push(@pattern, "${name}_Value");
push(@pattern, "${name}_URI");
push(@pattern, "${name}_Name");
} else {
push(@pattern, $self->expr2sql( $args[1], $level ));
}
foreach my $literal (@literal) {
foreach my $pattern (@pattern) {
push(@regex, sprintf(qq(%s REGEXP %s), $literal, $pattern));
}
}
push(@where, '(' . join(' OR ', @regex) . ')');
return ({}, \@from, \@where);
};
$functions{ 'sparql:bound' } = sub {
my $self = shift;
my $parsed_vars = shift;
my $level = shift || \do{ my $a = 0 };
my @args = @_;
my (@from, @where);
my $literal = $self->expr2sql( $args[0], $level );
push(@where, sprintf(qq(%s IS NOT NULL), $literal));
return ({}, \@from, \@where);
};
$functions{ 'rdfquery:isNotBound' } = sub {
my $self = shift;
my $parsed_vars = shift;
my $level = shift || \do{ my $a = 0 };
my @args = @_;
my (@from, @where);
my $literal = $self->expr2sql( $args[0], $level );
push(@where, sprintf(qq(%s IS NULL), $literal));
return ({}, \@from, \@where);
};
$functions{ 'http://www.w3.org/2001/XMLSchema#integer' } = sub {
my $self = shift;
my $parsed_vars = shift;
my $level = shift || \do{ my $a = 0 };
my @args = @_;
my (@from, @where);
my $literal = $self->expr2sql( $args[0], $level );
push(@where, sprintf(qq((0 + %s)), $literal));
return ({}, \@from, \@where);
};
$functions{ 'http://www.w3.org/2001/XMLSchema#double' } =
$functions{ 'http://www.w3.org/2001/XMLSchema#decimal' } = sub {
my $self = shift;
my $parsed_vars = shift;
my $level = shift || \do{ my $a = 0 };
my @args = @_;
my (@from, @where);
if ($args[0] eq 'FUNCTION') {
Carp::confess;
}
my $literal = $self->expr2sql( $args[0], $level );
push(@where, sprintf(qq((0.0 + %s)), $literal));
return ({}, \@from, \@where);
};
}
1;
__END__
=back
=head1 AUTHOR
Gregory Williams <gwilliams@cpan.org>
=cut
|