1 package # Hide from PAUSE
2 DBIx::Class::SQLAHacks;
4 # This module is a subclass of SQL::Abstract::Limit and includes a number
5 # of DBIC-specific workarounds, not yet suitable for inclusion into the
8 use base qw/SQL::Abstract::Limit/;
11 use List::Util 'first';
12 use Sub::Name 'subname';
14 use Carp::Clan qw/^DBIx::Class|^SQL::Abstract|^Try::Tiny/;
17 # reinstall the carp()/croak() functions imported into SQL::Abstract
18 # as Carp and Carp::Clan do not like each other much
19 no warnings qw/redefine/;
21 for my $f (qw/carp croak/) {
23 my $orig = \&{"SQL::Abstract::$f"};
24 *{"SQL::Abstract::$f"} = subname "SQL::Abstract::$f" =>
26 if (Carp::longmess() =~ /DBIx::Class::SQLAHacks::[\w]+ .+? called \s at/x) {
27 __PACKAGE__->can($f)->(@_);
36 # the "oh noes offset/top without limit" constant
37 sub __max_int { 0xFFFFFFFF };
40 # Tries to determine limit dialect.
43 my $self = shift->SUPER::new(@_);
45 # This prevents the caching of $dbh in S::A::L, I believe
46 # If limit_dialect is a ref (like a $dbh), go ahead and replace
47 # it with what it resolves to:
48 $self->{limit_dialect} = $self->_find_syntax($self->{limit_dialect})
49 if ref $self->{limit_dialect};
54 # !!! THIS IS ALSO HORRIFIC !!! /me ashamed
56 # Generates inner/outer select lists for various limit dialects
57 # which result in one or more subqueries (e.g. RNO, Top, RowNum)
58 # Any non-root-table columns need to have their table qualifier
59 # turned into a column alias (otherwise names in subqueries clash
60 # and/or lose their source table)
62 # Returns inner/outer strings of SQL QUOTED selectors with aliases
63 # (to be used in whatever select statement), and an alias index hashref
64 # of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used for string-subst
66 # If an order_by is supplied, the inner select needs to bring out columns
67 # used in implicit (non-selected) orders, and the order condition itself
68 # needs to be realiased to the proper names in the outer query. Thus we
69 # also return a hashref (order doesn't matter) of QUOTED EXTRA-SEL =>
70 # QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
71 # exist in the original select list
73 sub _subqueried_limit_attrs {
74 my ($self, $rs_attrs) = @_;
76 croak 'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
77 unless ref ($rs_attrs) eq 'HASH';
79 my ($re_sep, $re_alias) = map { quotemeta $_ } (
80 $self->name_sep || '.',
84 # correlate select and as, build selection index
85 my (@sel, $in_sel_index);
86 for my $i (0 .. $#{$rs_attrs->{select}}) {
88 my $s = $rs_attrs->{select}[$i];
89 my $sql_sel = $self->_recurse_fields ($s);
90 my $sql_alias = (ref $s) eq 'HASH' ? $s->{-as} : undef;
95 unquoted_sql => do { local $self->{quote_char}; $self->_recurse_fields ($s) },
101 croak "Select argument $i ($s) without corresponding 'as'"
105 $in_sel_index->{$sql_sel}++;
106 $in_sel_index->{$self->_quote ($sql_alias)}++ if $sql_alias;
108 # record unqualified versions too, so we do not have
109 # to reselect the same column twice (in qualified and
111 if (! ref $s && $sql_sel =~ / $re_sep (.+) $/x) {
112 $in_sel_index->{$1}++;
117 # re-alias and remove any name separators from aliases,
118 # unless we are dealing with the current source alias
119 # (which will transcend the subqueries as it is necessary
120 # for possible further chaining)
121 my (@in_sel, @out_sel, %renamed);
122 for my $node (@sel) {
123 if (first { $_ =~ / (?<! $re_alias ) $re_sep /x } ($node->{as}, $node->{unquoted_sql}) ) {
124 $node->{as} =~ s/ $re_sep /__/xg;
125 my $quoted_as = $self->_quote($node->{as});
126 push @in_sel, sprintf '%s AS %s', $node->{sql}, $quoted_as;
127 push @out_sel, $quoted_as;
128 $renamed{$node->{sql}} = $quoted_as;
131 push @in_sel, $node->{sql};
132 push @out_sel, $self->_quote ($node->{as});
136 # see if the order gives us anything
138 for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
140 $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
141 $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
143 next if $in_sel_index->{$chunk};
145 $extra_order_sel{$chunk} ||= $self->_quote (
146 'ORDER__BY__' . scalar keys %extra_order_sel
151 (map { join (', ', @$_ ) } (
156 keys %extra_order_sel ? \%extra_order_sel : (),
160 # ANSI standard Limit/Offset implementation. DB2 and MSSQL >= 2005 use this
162 my ($self, $sql, $rs_attrs, $rows, $offset ) = @_;
164 # mangle the input sql as we will be replacing the selector
165 $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
166 or croak "Unrecognizable SELECT: $sql";
168 # get selectors, and scan the order_by (if any)
169 my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
170 = $self->_subqueried_limit_attrs ( $rs_attrs );
172 # make up an order if none exists
173 my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
174 my $rno_ord = $self->_order_by ($requested_order);
176 # this is the order supplement magic
177 my $mid_sel = $out_sel;
178 if ($extra_order_sel) {
179 for my $extra_col (sort
180 { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
181 keys %$extra_order_sel
183 $in_sel .= sprintf (', %s AS %s',
185 $extra_order_sel->{$extra_col},
188 $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
192 # and this is order re-alias magic
193 for ($extra_order_sel, $alias_map) {
194 for my $col (keys %$_) {
195 my $re_col = quotemeta ($col);
196 $rno_ord =~ s/$re_col/$_->{$col}/;
200 # whatever is left of the order_by (only where is processed at this point)
201 my $group_having = $self->_parse_rs_attrs($rs_attrs);
203 my $qalias = $self->_quote ($rs_attrs->{alias});
204 my $idx_name = $self->_quote ('rno__row__index');
206 $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
208 SELECT $out_sel FROM (
209 SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
210 SELECT $in_sel ${sql}${group_having}
212 ) $qalias WHERE $idx_name BETWEEN %u AND %u
216 $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
220 # some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
221 sub _rno_default_order {
225 # Informix specific limit, almost like LIMIT/OFFSET
227 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
229 $sql =~ s/^ \s* SELECT \s+ //ix
230 or croak "Unrecognizable SELECT: $sql";
232 return sprintf ('SELECT %s%s%s%s',
234 ? sprintf ('SKIP %u ', $offset)
237 sprintf ('FIRST %u ', $rows),
239 $self->_parse_rs_attrs ($rs_attrs),
243 # Firebird specific limit, reverse of _SkipFirst for Informix
245 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
247 $sql =~ s/^ \s* SELECT \s+ //ix
248 or croak "Unrecognizable SELECT: $sql";
250 return sprintf ('SELECT %s%s%s%s',
251 sprintf ('FIRST %u ', $rows),
253 ? sprintf ('SKIP %u ', $offset)
257 $self->_parse_rs_attrs ($rs_attrs),
263 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
265 # mangle the input sql as we will be replacing the selector
266 $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
267 or croak "Unrecognizable SELECT: $sql";
269 my ($insel, $outsel) = $self->_subqueried_limit_attrs ($rs_attrs);
271 my $qalias = $self->_quote ($rs_attrs->{alias});
272 my $idx_name = $self->_quote ('rownum__index');
273 my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
275 $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
277 SELECT $outsel FROM (
278 SELECT $outsel, ROWNUM $idx_name FROM (
279 SELECT $insel ${sql}${order_group_having}
281 ) $qalias WHERE $idx_name BETWEEN %u AND %u
285 $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
289 # Crappy Top based Limit/Offset support. Legacy for MSSQL < 2005
291 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
293 # mangle the input sql as we will be replacing the selector
294 $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
295 or croak "Unrecognizable SELECT: $sql";
298 my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
299 = $self->_subqueried_limit_attrs ($rs_attrs);
301 my $requested_order = delete $rs_attrs->{order_by};
303 my $order_by_requested = $self->_order_by ($requested_order);
305 # make up an order unless supplied
306 my $inner_order = ($order_by_requested
309 { join ('', $rs_attrs->{alias}, $self->{name_sep}||'.', $_ ) }
310 ( $rs_attrs->{_rsroot_source_handle}->resolve->_pri_cols )
314 my ($order_by_inner, $order_by_reversed);
316 # localise as we already have all the bind values we need
318 local $self->{order_bind};
319 $order_by_inner = $self->_order_by ($inner_order);
322 for my $ch ($self->_order_by_chunks ($inner_order)) {
323 $ch = $ch->[0] if ref $ch eq 'ARRAY';
325 $ch =~ s/\s+ ( ASC|DESC ) \s* $//ix;
326 my $dir = uc ($1||'ASC');
328 push @out_chunks, \join (' ', $ch, $dir eq 'ASC' ? 'DESC' : 'ASC' );
331 $order_by_reversed = $self->_order_by (\@out_chunks);
334 # this is the order supplement magic
335 my $mid_sel = $out_sel;
336 if ($extra_order_sel) {
337 for my $extra_col (sort
338 { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
339 keys %$extra_order_sel
341 $in_sel .= sprintf (', %s AS %s',
343 $extra_order_sel->{$extra_col},
346 $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
349 # since whatever order bindvals there are, they will be realiased
350 # and need to show up in front of the entire initial inner subquery
351 # Unshift *from_bind* to make this happen (horrible, horrible, but
352 # we don't have another mechanism yet)
353 unshift @{$self->{from_bind}}, @{$self->{order_bind}};
356 # and this is order re-alias magic
357 for my $map ($extra_order_sel, $alias_map) {
358 for my $col (keys %$map) {
359 my $re_col = quotemeta ($col);
360 $_ =~ s/$re_col/$map->{$col}/
361 for ($order_by_reversed, $order_by_requested);
365 # generate the rest of the sql
366 my $grpby_having = $self->_parse_rs_attrs ($rs_attrs);
368 my $quoted_rs_alias = $self->_quote ($rs_attrs->{alias});
370 $sql = sprintf ('SELECT TOP %u %s %s %s %s',
371 $rows + ($offset||0),
378 $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
386 $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
392 ) if ( ($offset && $order_by_requested) || ($mid_sel ne $out_sel) );
394 $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
398 # This for Sybase ASE, to use SET ROWCOUNT when there is no offset, and
399 # GenericSubQ otherwise.
400 sub _RowCountOrGenericSubQ {
402 my ($sql, $rs_attrs, $rows, $offset) = @_;
404 return $self->_GenericSubQ(@_) if $offset;
406 return sprintf <<"EOF", $rows, $sql;
413 # This is the most evil limit "dialect" (more of a hack) for *really*
414 # stupid databases. It works by ordering the set by some unique column,
415 # and calculating amount of rows that have a less-er value (thus
416 # emulating a RowNum-like index). Of course this implies the set can
417 # only be ordered by a single unique columns.
419 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
421 my $root_rsrc = $rs_attrs->{_rsroot_source_handle}->resolve;
422 my $root_tbl_name = $root_rsrc->name;
424 # mangle the input sql as we will be replacing the selector
425 $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
426 or croak "Unrecognizable SELECT: $sql";
428 my ($order_by, @rest) = do {
429 local $self->{quote_char};
430 $self->_order_by_chunks ($rs_attrs->{order_by})
440 ( ref $order_by eq 'ARRAY' and @$order_by == 1 )
444 'Generic Subquery Limit does not work on resultsets without an order, or resultsets '
445 . 'with complex order criteria (multicolumn and/or functions). Provide a single, '
446 . 'unique-column order criteria.'
450 ($order_by) = @$order_by if ref $order_by;
452 $order_by =~ s/\s+ ( ASC|DESC ) \s* $//ix;
453 my $direction = lc ($1 || 'asc');
455 my ($unq_sort_col) = $order_by =~ /(?:^|\.)([^\.]+)$/;
457 my $inf = $root_rsrc->storage->_resolve_column_info (
458 $rs_attrs->{from}, [$order_by, $unq_sort_col]
461 my $ord_colinfo = $inf->{$order_by} || croak "Unable to determine source of order-criteria '$order_by'";
463 if ($ord_colinfo->{-result_source}->name ne $root_tbl_name) {
464 croak "Generic Subquery Limit order criteria can be only based on the root-source '"
465 . $root_rsrc->source_name . "' (aliased as '$rs_attrs->{alias}')";
468 # make sure order column is qualified
469 $order_by = "$rs_attrs->{alias}.$order_by"
470 unless $order_by =~ /^$rs_attrs->{alias}\./;
473 my $ucs = { $root_rsrc->unique_constraints };
474 for (values %$ucs ) {
475 if (@$_ == 1 && "$rs_attrs->{alias}.$_->[0]" eq $order_by) {
480 croak "Generic Subquery Limit order criteria column '$order_by' must be unique (no unique constraint found)"
483 my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
484 = $self->_subqueried_limit_attrs ($rs_attrs);
486 my $cmp_op = $direction eq 'desc' ? '>' : '<';
487 my $count_tbl_alias = 'rownum__emulation';
489 my $order_sql = $self->_order_by (delete $rs_attrs->{order_by});
490 my $group_having_sql = $self->_parse_rs_attrs($rs_attrs);
492 # add the order supplement (if any) as this is what will be used for the outer WHERE
493 $in_sel .= ", $_" for keys %{$extra_order_sel||{}};
495 $sql = sprintf (<<EOS,
498 SELECT $in_sel ${sql}${group_having_sql}
500 WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) %s
503 ( map { $self->_quote ($_) } (
507 "$count_tbl_alias.$unq_sort_col",
511 ? sprintf ('BETWEEN %u AND %u', $offset, $offset + $rows - 1)
512 : sprintf ('< %u', $rows )
516 $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
521 # While we're at it, this should make LIMIT queries more efficient,
522 # without digging into things too deeply
524 my ($self, $syntax) = @_;
525 return $self->{_cached_syntax} ||= $self->SUPER::_find_syntax($syntax);
528 # Quotes table names, handles "limit" dialects (e.g. where rownum between x and
531 my ($self, $table, $fields, $where, $rs_attrs, @rest) = @_;
533 if (not ref($table) or ref($table) eq 'SCALAR') {
534 $table = $self->_quote($table);
537 @rest = (-1) unless defined $rest[0];
538 croak "LIMIT 0 Does Not Compute" if $rest[0] == 0;
539 # and anyway, SQL::Abstract::Limit will cause a barf if we don't first
541 my ($sql, @bind) = $self->SUPER::select(
542 $table, $self->_recurse_fields($fields), $where, $rs_attrs, @rest
544 push @{$self->{where_bind}}, @bind;
546 # this *must* be called, otherwise extra binds will remain in the sql-maker
547 my @all_bind = $self->_assemble_binds;
549 return wantarray ? ($sql, @all_bind) : $sql;
552 sub _assemble_binds {
554 return map { @{ (delete $self->{"${_}_bind"}) || [] } } (qw/from where having order/);
557 # Quotes table names, and handles default inserts
561 $table = $self->_quote($table);
563 # SQLA will emit INSERT INTO $table ( ) VALUES ( )
564 # which is sadly understood only by MySQL. Change default behavior here,
565 # until SQLA2 comes with proper dialect support
566 if (! $_[0] or (ref $_[0] eq 'HASH' and !keys %{$_[0]} ) ) {
567 my $sql = "INSERT INTO ${table} DEFAULT VALUES";
569 if (my $ret = ($_[1]||{})->{returning} ) {
570 $sql .= $self->_insert_returning ($ret);
576 $self->SUPER::insert($table, @_);
579 # Just quotes table names.
583 $table = $self->_quote($table);
584 $self->SUPER::update($table, @_);
587 # Just quotes table names.
591 $table = $self->_quote($table);
592 $self->SUPER::delete($table, @_);
597 # my ( $syntax, $sql, $order, $rows, $offset ) = @_;
600 return $_[1] . $self->_parse_rs_attrs($_[2]);
602 return $self->SUPER::_emulate_limit(@_);
606 sub _recurse_fields {
607 my ($self, $fields) = @_;
608 my $ref = ref $fields;
609 return $self->_quote($fields) unless $ref;
610 return $$fields if $ref eq 'SCALAR';
612 if ($ref eq 'ARRAY') {
613 return join(', ', map { $self->_recurse_fields($_) } @$fields);
615 elsif ($ref eq 'HASH') {
616 my %hash = %$fields; # shallow copy
618 my $as = delete $hash{-as}; # if supplied
620 my ($func, $args, @toomany) = %hash;
622 # there should be only one pair
624 croak "Malformed select argument - too many keys in hash: " . join (',', keys %$fields );
627 if (lc ($func) eq 'distinct' && ref $args eq 'ARRAY' && @$args > 1) {
629 'The select => { distinct => ... } syntax is not supported for multiple columns.'
630 .' Instead please use { group_by => [ qw/' . (join ' ', @$args) . '/ ] }'
631 .' or { select => [ qw/' . (join ' ', @$args) . '/ ], distinct => 1 }'
635 my $select = sprintf ('%s( %s )%s',
636 $self->_sqlcase($func),
637 $self->_recurse_fields($args),
639 ? sprintf (' %s %s', $self->_sqlcase('as'), $self->_quote ($as) )
645 # Is the second check absolutely necessary?
646 elsif ( $ref eq 'REF' and ref($$fields) eq 'ARRAY' ) {
647 return $self->_fold_sqlbind( $fields );
650 croak($ref . qq{ unexpected in _recurse_fields()})
655 update => 'FOR UPDATE',
656 shared => 'FOR SHARE',
659 # this used to be a part of _order_by but is broken out for clarity.
660 # What we have been doing forever is hijacking the $order arg of
661 # SQLA::select to pass in arbitrary pieces of data (first the group_by,
662 # then pretty much the entire resultset attr-hash, as more and more
663 # things in the SQLA space need to have mopre info about the $rs they
664 # create SQL for. The alternative would be to keep expanding the
665 # signature of _select with more and more positional parameters, which
666 # is just gross. All hail SQLA2!
667 sub _parse_rs_attrs {
668 my ($self, $arg) = @_;
672 if (my $g = $self->_recurse_fields($arg->{group_by}) ) {
673 $sql .= $self->_sqlcase(' group by ') . $g;
676 if (defined $arg->{having}) {
677 my ($frag, @bind) = $self->_recurse_where($arg->{having});
678 push(@{$self->{having_bind}}, @bind);
679 $sql .= $self->_sqlcase(' having ') . $frag;
682 if (defined $arg->{order_by}) {
683 $sql .= $self->_order_by ($arg->{order_by});
686 if (my $for = $arg->{for}) {
687 $sql .= " $for_syntax->{$for}" if $for_syntax->{$for};
694 my ($self, $arg) = @_;
696 # check that we are not called in legacy mode (order_by as 4th argument)
697 if (ref $arg eq 'HASH' and not grep { $_ =~ /^-(?:desc|asc)/i } keys %$arg ) {
698 return $self->_parse_rs_attrs ($arg);
701 my ($sql, @bind) = $self->SUPER::_order_by ($arg);
702 push @{$self->{order_bind}}, @bind;
707 sub _order_directions {
708 my ($self, $order) = @_;
710 # strip bind values - none of the current _order_directions users support them
711 return $self->SUPER::_order_directions( [ map
712 { ref $_ ? $_->[0] : $_ }
713 $self->_order_by_chunks ($order)
718 my ($self, $from) = @_;
719 if (ref $from eq 'ARRAY') {
720 return $self->_recurse_from(@$from);
721 } elsif (ref $from eq 'HASH') {
722 return $self->_make_as($from);
724 return $from; # would love to quote here but _table ends up getting called
725 # twice during an ->select without a limit clause due to
726 # the way S::A::Limit->select works. should maybe consider
727 # bypassing this and doing S::A::select($self, ...) in
728 # our select method above. meantime, quoting shims have
729 # been added to select/insert/update/delete here
733 sub _generate_join_clause {
734 my ($self, $join_type) = @_;
736 return sprintf ('%s JOIN ',
737 $join_type ? ' ' . uc($join_type) : ''
742 my ($self, $from, @join) = @_;
744 push(@sqlf, $self->_make_as($from));
745 foreach my $j (@join) {
749 # check whether a join type exists
750 my $to_jt = ref($to) eq 'ARRAY' ? $to->[0] : $to;
752 if (ref($to_jt) eq 'HASH' and defined($to_jt->{-join_type})) {
753 $join_type = $to_jt->{-join_type};
754 $join_type =~ s/^\s+ | \s+$//xg;
757 $join_type = $self->{_default_jointype} if not defined $join_type;
759 push @sqlf, $self->_generate_join_clause( $join_type );
761 if (ref $to eq 'ARRAY') {
762 push(@sqlf, '(', $self->_recurse_from(@$to), ')');
764 push(@sqlf, $self->_make_as($to));
766 push(@sqlf, ' ON ', $self->_join_condition($on));
768 return join('', @sqlf);
772 my ($self, $sqlbind) = @_;
774 my @sqlbind = @$$sqlbind; # copy
775 my $sql = shift @sqlbind;
776 push @{$self->{from_bind}}, @sqlbind;
782 my ($self, $from) = @_;
783 return join(' ', map { (ref $_ eq 'SCALAR' ? $$_
784 : ref $_ eq 'REF' ? $self->_fold_sqlbind($_)
786 } reverse each %{$self->_skip_options($from)});
790 my ($self, $hash) = @_;
792 $clean_hash->{$_} = $hash->{$_}
793 for grep {!/^-/} keys %$hash;
797 sub _join_condition {
798 my ($self, $cond) = @_;
799 if (ref $cond eq 'HASH') {
804 croak (ref($v) . qq{ reference arguments are not supported in JOINS - try using \"..." instead'})
805 if ref($v) ne 'SCALAR';
809 my $x = '= '.$self->_quote($v); $j{$_} = \$x;
812 return scalar($self->_recurse_where(\%j));
813 } elsif (ref $cond eq 'ARRAY') {
814 return join(' OR ', map { $self->_join_condition($_) } @$cond);
816 die "Can't handle this yet!";
823 $self->{limit_dialect} = shift;
824 undef $self->{_cached_syntax};
826 return $self->{limit_dialect};
829 # Set to an array-ref to specify separate left and right quotes for table names.
830 # A single scalar is equivalen to [ $char, $char ]
833 $self->{quote_char} = shift if @_;
834 return $self->{quote_char};
837 # Character separating quoted table names.
840 $self->{name_sep} = shift if @_;
841 return $self->{name_sep};