# SQL::Abstract::Limit, which proved to be very hard to keep updated
use base qw/
+ DBIx::Class::SQLAHacks::LimitDialects
SQL::Abstract
Class::Accessor::Grouped
/;
use mro 'c3';
use strict;
use warnings;
-use List::Util 'first';
use Sub::Name 'subname';
use Carp::Clan qw/^DBIx::Class|^SQL::Abstract|^Try::Tiny/;
use namespace::clean;
# as the value to abuse with MSSQL ordered subqueries)
sub __max_int { 0xFFFFFFFF };
-# !!! THIS IS ALSO HORRIFIC !!! /me ashamed
-#
-# Generates inner/outer select lists for various limit dialects
-# which result in one or more subqueries (e.g. RNO, Top, RowNum)
-# Any non-root-table columns need to have their table qualifier
-# turned into a column alias (otherwise names in subqueries clash
-# and/or lose their source table)
-#
-# Returns inner/outer strings of SQL QUOTED selectors with aliases
-# (to be used in whatever select statement), and an alias index hashref
-# of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used for string-subst
-# higher up).
-# If an order_by is supplied, the inner select needs to bring out columns
-# used in implicit (non-selected) orders, and the order condition itself
-# needs to be realiased to the proper names in the outer query. Thus we
-# also return a hashref (order doesn't matter) of QUOTED EXTRA-SEL =>
-# QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
-# exist in the original select list
-
-sub _subqueried_limit_attrs {
- my ($self, $rs_attrs) = @_;
-
- croak 'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
- unless ref ($rs_attrs) eq 'HASH';
-
- my ($re_sep, $re_alias) = map { quotemeta $_ } (
- $self->name_sep || '.',
- $rs_attrs->{alias},
- );
-
- # correlate select and as, build selection index
- my (@sel, $in_sel_index);
- for my $i (0 .. $#{$rs_attrs->{select}}) {
-
- my $s = $rs_attrs->{select}[$i];
- my $sql_sel = $self->_recurse_fields ($s);
- my $sql_alias = (ref $s) eq 'HASH' ? $s->{-as} : undef;
-
-
- push @sel, {
- sql => $sql_sel,
- unquoted_sql => do { local $self->{quote_char}; $self->_recurse_fields ($s) },
- as =>
- $sql_alias
- ||
- $rs_attrs->{as}[$i]
- ||
- croak "Select argument $i ($s) without corresponding 'as'"
- ,
- };
-
- $in_sel_index->{$sql_sel}++;
- $in_sel_index->{$self->_quote ($sql_alias)}++ if $sql_alias;
-
- # record unqualified versions too, so we do not have
- # to reselect the same column twice (in qualified and
- # unqualified form)
- if (! ref $s && $sql_sel =~ / $re_sep (.+) $/x) {
- $in_sel_index->{$1}++;
- }
- }
-
-
- # re-alias and remove any name separators from aliases,
- # unless we are dealing with the current source alias
- # (which will transcend the subqueries as it is necessary
- # for possible further chaining)
- my (@in_sel, @out_sel, %renamed);
- for my $node (@sel) {
- if (first { $_ =~ / (?<! ^ $re_alias ) $re_sep /x } ($node->{as}, $node->{unquoted_sql}) ) {
- $node->{as} = $self->_unqualify_colname($node->{as});
- my $quoted_as = $self->_quote($node->{as});
- push @in_sel, sprintf '%s AS %s', $node->{sql}, $quoted_as;
- push @out_sel, $quoted_as;
- $renamed{$node->{sql}} = $quoted_as;
- }
- else {
- push @in_sel, $node->{sql};
- push @out_sel, $self->_quote ($node->{as});
- }
- }
-
- # see if the order gives us anything
- my %extra_order_sel;
- for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
- # order with bind
- $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
- $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
-
- next if $in_sel_index->{$chunk};
-
- $extra_order_sel{$chunk} ||= $self->_quote (
- 'ORDER__BY__' . scalar keys %extra_order_sel
- );
- }
-
- return (
- (map { join (', ', @$_ ) } (
- \@in_sel,
- \@out_sel)
- ),
- \%renamed,
- keys %extra_order_sel ? \%extra_order_sel : (),
- );
-}
-
-sub _unqualify_colname {
- my ($self, $fqcn) = @_;
- my $re_sep = quotemeta($self->name_sep || '.');
- $fqcn =~ s/ $re_sep /__/xg;
- return $fqcn;
-}
-
-#
-# Follow limit dialect implementations
-#
-
-# PostgreSQL and SQLite
-sub _LimitOffset {
- my ( $self, $sql, $order, $rows, $offset ) = @_;
- $sql .= $self->_order_by( $order ) . " LIMIT $rows";
- $sql .= " OFFSET $offset" if +$offset;
- return $sql;
-}
-
-# MySQL and any SQL::Statement based DBD
-sub _LimitXY {
- my ( $self, $sql, $order, $rows, $offset ) = @_;
- $sql .= $self->_order_by( $order ) . " LIMIT ";
- $sql .= "$offset, " if +$offset;
- $sql .= $rows;
- return $sql;
-}
-
-# ANSI standard Limit/Offset implementation. DB2 and MSSQL >= 2005 use this
-sub _RowNumberOver {
- my ($self, $sql, $rs_attrs, $rows, $offset ) = @_;
-
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or croak "Unrecognizable SELECT: $sql";
-
- # get selectors, and scan the order_by (if any)
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ( $rs_attrs );
-
- # make up an order if none exists
- my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
- my $rno_ord = $self->_order_by ($requested_order);
-
- # this is the order supplement magic
- my $mid_sel = $out_sel;
- if ($extra_order_sel) {
- for my $extra_col (sort
- { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
- keys %$extra_order_sel
- ) {
- $in_sel .= sprintf (', %s AS %s',
- $extra_col,
- $extra_order_sel->{$extra_col},
- );
-
- $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
- }
- }
-
- # and this is order re-alias magic
- for ($extra_order_sel, $alias_map) {
- for my $col (keys %$_) {
- my $re_col = quotemeta ($col);
- $rno_ord =~ s/$re_col/$_->{$col}/;
- }
- }
-
- # whatever is left of the order_by (only where is processed at this point)
- my $group_having = $self->_parse_rs_attrs($rs_attrs);
-
- my $qalias = $self->_quote ($rs_attrs->{alias});
- my $idx_name = $self->_quote ('rno__row__index');
-
- $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
-
-SELECT $out_sel FROM (
- SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
- SELECT $in_sel ${sql}${group_having}
- ) $qalias
-) $qalias WHERE $idx_name BETWEEN %u AND %u
-
-EOS
-
- $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
- return $sql;
-}
-
-# some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
-sub _rno_default_order {
- return undef;
-}
-
-# Informix specific limit, almost like LIMIT/OFFSET
-# According to SQLA::Limit informix also supports
-# SKIP X LIMIT Y (in addition to SKIP X FIRST Y)
-sub _SkipFirst {
- my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
-
- $sql =~ s/^ \s* SELECT \s+ //ix
- or croak "Unrecognizable SELECT: $sql";
-
- return sprintf ('SELECT %s%s%s%s',
- $offset
- ? sprintf ('SKIP %u ', $offset)
- : ''
- ,
- sprintf ('FIRST %u ', $rows),
- $sql,
- $self->_parse_rs_attrs ($rs_attrs),
- );
-}
-
-# Firebird specific limit, reverse of _SkipFirst for Informix
-# According to SQLA::Limit firebird/interbase also supports
-# ROWS X TO Y (in addition to FIRST X SKIP Y)
-sub _FirstSkip {
- my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
-
- $sql =~ s/^ \s* SELECT \s+ //ix
- or croak "Unrecognizable SELECT: $sql";
-
- return sprintf ('SELECT %s%s%s%s',
- sprintf ('FIRST %u ', $rows),
- $offset
- ? sprintf ('SKIP %u ', $offset)
- : ''
- ,
- $sql,
- $self->_parse_rs_attrs ($rs_attrs),
- );
-}
-
-# WhOracle limits
-sub _RowNum {
- my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
-
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or croak "Unrecognizable SELECT: $sql";
-
- my ($insel, $outsel) = $self->_subqueried_limit_attrs ($rs_attrs);
-
- my $qalias = $self->_quote ($rs_attrs->{alias});
- my $idx_name = $self->_quote ('rownum__index');
- my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
-
- $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
-
-SELECT $outsel FROM (
- SELECT $outsel, ROWNUM $idx_name FROM (
- SELECT $insel ${sql}${order_group_having}
- ) $qalias
-) $qalias WHERE $idx_name BETWEEN %u AND %u
-
-EOS
-
- $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
- return $sql;
-}
-
-# Crappy Top based Limit/Offset support. Legacy for MSSQL < 2005
-sub _Top {
- my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
-
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or croak "Unrecognizable SELECT: $sql";
-
- # get selectors
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ($rs_attrs);
-
- my $requested_order = delete $rs_attrs->{order_by};
-
- my $order_by_requested = $self->_order_by ($requested_order);
-
- # make up an order unless supplied
- my $inner_order = ($order_by_requested
- ? $requested_order
- : [ map
- { join ('', $rs_attrs->{alias}, $self->{name_sep}||'.', $_ ) }
- ( $rs_attrs->{_rsroot_source_handle}->resolve->_pri_cols )
- ]
- );
-
- my ($order_by_inner, $order_by_reversed);
-
- # localise as we already have all the bind values we need
- {
- local $self->{order_bind};
- $order_by_inner = $self->_order_by ($inner_order);
-
- my @out_chunks;
- for my $ch ($self->_order_by_chunks ($inner_order)) {
- $ch = $ch->[0] if ref $ch eq 'ARRAY';
-
- $ch =~ s/\s+ ( ASC|DESC ) \s* $//ix;
- my $dir = uc ($1||'ASC');
-
- push @out_chunks, \join (' ', $ch, $dir eq 'ASC' ? 'DESC' : 'ASC' );
- }
-
- $order_by_reversed = $self->_order_by (\@out_chunks);
- }
-
- # this is the order supplement magic
- my $mid_sel = $out_sel;
- if ($extra_order_sel) {
- for my $extra_col (sort
- { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
- keys %$extra_order_sel
- ) {
- $in_sel .= sprintf (', %s AS %s',
- $extra_col,
- $extra_order_sel->{$extra_col},
- );
-
- $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
- }
-
- # since whatever order bindvals there are, they will be realiased
- # and need to show up in front of the entire initial inner subquery
- # Unshift *from_bind* to make this happen (horrible, horrible, but
- # we don't have another mechanism yet)
- unshift @{$self->{from_bind}}, @{$self->{order_bind}};
- }
-
- # and this is order re-alias magic
- for my $map ($extra_order_sel, $alias_map) {
- for my $col (keys %$map) {
- my $re_col = quotemeta ($col);
- $_ =~ s/$re_col/$map->{$col}/
- for ($order_by_reversed, $order_by_requested);
- }
- }
-
- # generate the rest of the sql
- my $grpby_having = $self->_parse_rs_attrs ($rs_attrs);
-
- my $quoted_rs_alias = $self->_quote ($rs_attrs->{alias});
-
- $sql = sprintf ('SELECT TOP %u %s %s %s %s',
- $rows + ($offset||0),
- $in_sel,
- $sql,
- $grpby_having,
- $order_by_inner,
- );
-
- $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
- $rows,
- $mid_sel,
- $sql,
- $quoted_rs_alias,
- $order_by_reversed,
- ) if $offset;
-
- $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
- $rows,
- $out_sel,
- $sql,
- $quoted_rs_alias,
- $order_by_requested,
- ) if ( ($offset && $order_by_requested) || ($mid_sel ne $out_sel) );
-
- $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
- return $sql;
-}
-
-# This for Sybase ASE, to use SET ROWCOUNT when there is no offset, and
-# GenericSubQ otherwise.
-sub _RowCountOrGenericSubQ {
- my $self = shift;
- my ($sql, $rs_attrs, $rows, $offset) = @_;
-
- return $self->_GenericSubQ(@_) if $offset;
-
- return sprintf <<"EOF", $rows, $sql;
-SET ROWCOUNT %d
-%s
-SET ROWCOUNT 0
-EOF
-}
-
-# This is the most evil limit "dialect" (more of a hack) for *really*
-# stupid databases. It works by ordering the set by some unique column,
-# and calculating amount of rows that have a less-er value (thus
-# emulating a RowNum-like index). Of course this implies the set can
-# only be ordered by a single unique columns.
-sub _GenericSubQ {
- my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
-
- my $root_rsrc = $rs_attrs->{_rsroot_source_handle}->resolve;
- my $root_tbl_name = $root_rsrc->name;
-
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or croak "Unrecognizable SELECT: $sql";
-
- my ($order_by, @rest) = do {
- local $self->{quote_char};
- $self->_order_by_chunks ($rs_attrs->{order_by})
- };
-
- unless (
- $order_by
- &&
- ! @rest
- &&
- ( ! ref $order_by
- ||
- ( ref $order_by eq 'ARRAY' and @$order_by == 1 )
- )
- ) {
- croak (
- 'Generic Subquery Limit does not work on resultsets without an order, or resultsets '
- . 'with complex order criteria (multicolumn and/or functions). Provide a single, '
- . 'unique-column order criteria.'
- );
- }
-
- ($order_by) = @$order_by if ref $order_by;
-
- $order_by =~ s/\s+ ( ASC|DESC ) \s* $//ix;
- my $direction = lc ($1 || 'asc');
-
- my ($unq_sort_col) = $order_by =~ /(?:^|\.)([^\.]+)$/;
-
- my $inf = $root_rsrc->storage->_resolve_column_info (
- $rs_attrs->{from}, [$order_by, $unq_sort_col]
- );
-
- my $ord_colinfo = $inf->{$order_by} || croak "Unable to determine source of order-criteria '$order_by'";
-
- if ($ord_colinfo->{-result_source}->name ne $root_tbl_name) {
- croak "Generic Subquery Limit order criteria can be only based on the root-source '"
- . $root_rsrc->source_name . "' (aliased as '$rs_attrs->{alias}')";
- }
-
- # make sure order column is qualified
- $order_by = "$rs_attrs->{alias}.$order_by"
- unless $order_by =~ /^$rs_attrs->{alias}\./;
-
- my $is_u;
- my $ucs = { $root_rsrc->unique_constraints };
- for (values %$ucs ) {
- if (@$_ == 1 && "$rs_attrs->{alias}.$_->[0]" eq $order_by) {
- $is_u++;
- last;
- }
- }
- croak "Generic Subquery Limit order criteria column '$order_by' must be unique (no unique constraint found)"
- unless $is_u;
-
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ($rs_attrs);
-
- my $cmp_op = $direction eq 'desc' ? '>' : '<';
- my $count_tbl_alias = 'rownum__emulation';
-
- my $order_sql = $self->_order_by (delete $rs_attrs->{order_by});
- my $group_having_sql = $self->_parse_rs_attrs($rs_attrs);
-
- # add the order supplement (if any) as this is what will be used for the outer WHERE
- $in_sel .= ", $_" for keys %{$extra_order_sel||{}};
-
- $sql = sprintf (<<EOS,
-SELECT $out_sel
- FROM (
- SELECT $in_sel ${sql}${group_having_sql}
- ) %s
-WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) %s
-$order_sql
-EOS
- ( map { $self->_quote ($_) } (
- $rs_attrs->{alias},
- $root_tbl_name,
- $count_tbl_alias,
- "$count_tbl_alias.$unq_sort_col",
- $order_by,
- )),
- $offset
- ? sprintf ('BETWEEN %u AND %u', $offset, $offset + $rows - 1)
- : sprintf ('< %u', $rows )
- ,
- );
-
- $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
- return $sql;
-}
-
-#
-# Actual SQL::Abstract overrid^Whacks
-#
-
# Handle limit-dialect selection
sub select {
my ($self, $table, $fields, $where, $rs_attrs, $limit, $offset) = @_;
}
}
-
1;
--- /dev/null
+package DBIx::Class::SQLAHacks::LimitDialects;
+
+use warnings;
+use strict;
+
+use Carp::Clan qw/^DBIx::Class|^SQL::Abstract|^Try::Tiny/;
+use List::Util 'first';
+use namespace::clean;
+
+# PostgreSQL and SQLite
+sub _LimitOffset {
+ my ( $self, $sql, $order, $rows, $offset ) = @_;
+ $sql .= $self->_order_by( $order ) . " LIMIT $rows";
+ $sql .= " OFFSET $offset" if +$offset;
+ return $sql;
+}
+
+# MySQL and any SQL::Statement based DBD
+sub _LimitXY {
+ my ( $self, $sql, $order, $rows, $offset ) = @_;
+ $sql .= $self->_order_by( $order ) . " LIMIT ";
+ $sql .= "$offset, " if +$offset;
+ $sql .= $rows;
+ return $sql;
+}
+# ANSI standard Limit/Offset implementation. DB2 and MSSQL >= 2005 use this
+sub _RowNumberOver {
+ my ($self, $sql, $rs_attrs, $rows, $offset ) = @_;
+
+ # mangle the input sql as we will be replacing the selector
+ $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ # get selectors, and scan the order_by (if any)
+ my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ( $rs_attrs );
+
+ # make up an order if none exists
+ my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
+ my $rno_ord = $self->_order_by ($requested_order);
+
+ # this is the order supplement magic
+ my $mid_sel = $out_sel;
+ if ($extra_order_sel) {
+ for my $extra_col (sort
+ { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
+ keys %$extra_order_sel
+ ) {
+ $in_sel .= sprintf (', %s AS %s',
+ $extra_col,
+ $extra_order_sel->{$extra_col},
+ );
+
+ $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
+ }
+ }
+
+ # and this is order re-alias magic
+ for ($extra_order_sel, $alias_map) {
+ for my $col (keys %$_) {
+ my $re_col = quotemeta ($col);
+ $rno_ord =~ s/$re_col/$_->{$col}/;
+ }
+ }
+
+ # whatever is left of the order_by (only where is processed at this point)
+ my $group_having = $self->_parse_rs_attrs($rs_attrs);
+
+ my $qalias = $self->_quote ($rs_attrs->{alias});
+ my $idx_name = $self->_quote ('rno__row__index');
+
+ $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
+
+SELECT $out_sel FROM (
+ SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
+ SELECT $in_sel ${sql}${group_having}
+ ) $qalias
+) $qalias WHERE $idx_name BETWEEN %u AND %u
+
+EOS
+
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
+ return $sql;
+}
+
+# some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
+sub _rno_default_order {
+ return undef;
+}
+
+# Informix specific limit, almost like LIMIT/OFFSET
+# According to SQLA::Limit informix also supports
+# SKIP X LIMIT Y (in addition to SKIP X FIRST Y)
+sub _SkipFirst {
+ my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
+
+ $sql =~ s/^ \s* SELECT \s+ //ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ return sprintf ('SELECT %s%s%s%s',
+ $offset
+ ? sprintf ('SKIP %u ', $offset)
+ : ''
+ ,
+ sprintf ('FIRST %u ', $rows),
+ $sql,
+ $self->_parse_rs_attrs ($rs_attrs),
+ );
+}
+
+# Firebird specific limit, reverse of _SkipFirst for Informix
+# According to SQLA::Limit firebird/interbase also supports
+# ROWS X TO Y (in addition to FIRST X SKIP Y)
+sub _FirstSkip {
+ my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
+
+ $sql =~ s/^ \s* SELECT \s+ //ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ return sprintf ('SELECT %s%s%s%s',
+ sprintf ('FIRST %u ', $rows),
+ $offset
+ ? sprintf ('SKIP %u ', $offset)
+ : ''
+ ,
+ $sql,
+ $self->_parse_rs_attrs ($rs_attrs),
+ );
+}
+
+# WhOracle limits
+sub _RowNum {
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+
+ # mangle the input sql as we will be replacing the selector
+ $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ my ($insel, $outsel) = $self->_subqueried_limit_attrs ($rs_attrs);
+
+ my $qalias = $self->_quote ($rs_attrs->{alias});
+ my $idx_name = $self->_quote ('rownum__index');
+ my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
+
+ $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
+
+SELECT $outsel FROM (
+ SELECT $outsel, ROWNUM $idx_name FROM (
+ SELECT $insel ${sql}${order_group_having}
+ ) $qalias
+) $qalias WHERE $idx_name BETWEEN %u AND %u
+
+EOS
+
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
+ return $sql;
+}
+
+# Crappy Top based Limit/Offset support. Legacy for MSSQL < 2005
+sub _Top {
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+
+ # mangle the input sql as we will be replacing the selector
+ $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ # get selectors
+ my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ($rs_attrs);
+
+ my $requested_order = delete $rs_attrs->{order_by};
+
+ my $order_by_requested = $self->_order_by ($requested_order);
+
+ # make up an order unless supplied
+ my $inner_order = ($order_by_requested
+ ? $requested_order
+ : [ map
+ { join ('', $rs_attrs->{alias}, $self->{name_sep}||'.', $_ ) }
+ ( $rs_attrs->{_rsroot_source_handle}->resolve->_pri_cols )
+ ]
+ );
+
+ my ($order_by_inner, $order_by_reversed);
+
+ # localise as we already have all the bind values we need
+ {
+ local $self->{order_bind};
+ $order_by_inner = $self->_order_by ($inner_order);
+
+ my @out_chunks;
+ for my $ch ($self->_order_by_chunks ($inner_order)) {
+ $ch = $ch->[0] if ref $ch eq 'ARRAY';
+
+ $ch =~ s/\s+ ( ASC|DESC ) \s* $//ix;
+ my $dir = uc ($1||'ASC');
+
+ push @out_chunks, \join (' ', $ch, $dir eq 'ASC' ? 'DESC' : 'ASC' );
+ }
+
+ $order_by_reversed = $self->_order_by (\@out_chunks);
+ }
+
+ # this is the order supplement magic
+ my $mid_sel = $out_sel;
+ if ($extra_order_sel) {
+ for my $extra_col (sort
+ { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
+ keys %$extra_order_sel
+ ) {
+ $in_sel .= sprintf (', %s AS %s',
+ $extra_col,
+ $extra_order_sel->{$extra_col},
+ );
+
+ $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
+ }
+
+ # since whatever order bindvals there are, they will be realiased
+ # and need to show up in front of the entire initial inner subquery
+ # Unshift *from_bind* to make this happen (horrible, horrible, but
+ # we don't have another mechanism yet)
+ unshift @{$self->{from_bind}}, @{$self->{order_bind}};
+ }
+
+ # and this is order re-alias magic
+ for my $map ($extra_order_sel, $alias_map) {
+ for my $col (keys %$map) {
+ my $re_col = quotemeta ($col);
+ $_ =~ s/$re_col/$map->{$col}/
+ for ($order_by_reversed, $order_by_requested);
+ }
+ }
+
+ # generate the rest of the sql
+ my $grpby_having = $self->_parse_rs_attrs ($rs_attrs);
+
+ my $quoted_rs_alias = $self->_quote ($rs_attrs->{alias});
+
+ $sql = sprintf ('SELECT TOP %u %s %s %s %s',
+ $rows + ($offset||0),
+ $in_sel,
+ $sql,
+ $grpby_having,
+ $order_by_inner,
+ );
+
+ $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
+ $rows,
+ $mid_sel,
+ $sql,
+ $quoted_rs_alias,
+ $order_by_reversed,
+ ) if $offset;
+
+ $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
+ $rows,
+ $out_sel,
+ $sql,
+ $quoted_rs_alias,
+ $order_by_requested,
+ ) if ( ($offset && $order_by_requested) || ($mid_sel ne $out_sel) );
+
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
+ return $sql;
+}
+
+# This for Sybase ASE, to use SET ROWCOUNT when there is no offset, and
+# GenericSubQ otherwise.
+sub _RowCountOrGenericSubQ {
+ my $self = shift;
+ my ($sql, $rs_attrs, $rows, $offset) = @_;
+
+ return $self->_GenericSubQ(@_) if $offset;
+
+ return sprintf <<"EOF", $rows, $sql;
+SET ROWCOUNT %d
+%s
+SET ROWCOUNT 0
+EOF
+}
+
+# This is the most evil limit "dialect" (more of a hack) for *really*
+# stupid databases. It works by ordering the set by some unique column,
+# and calculating amount of rows that have a less-er value (thus
+# emulating a RowNum-like index). Of course this implies the set can
+# only be ordered by a single unique columns.
+sub _GenericSubQ {
+ my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
+
+ my $root_rsrc = $rs_attrs->{_rsroot_source_handle}->resolve;
+ my $root_tbl_name = $root_rsrc->name;
+
+ # mangle the input sql as we will be replacing the selector
+ $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ my ($order_by, @rest) = do {
+ local $self->{quote_char};
+ $self->_order_by_chunks ($rs_attrs->{order_by})
+ };
+
+ unless (
+ $order_by
+ &&
+ ! @rest
+ &&
+ ( ! ref $order_by
+ ||
+ ( ref $order_by eq 'ARRAY' and @$order_by == 1 )
+ )
+ ) {
+ croak (
+ 'Generic Subquery Limit does not work on resultsets without an order, or resultsets '
+ . 'with complex order criteria (multicolumn and/or functions). Provide a single, '
+ . 'unique-column order criteria.'
+ );
+ }
+
+ ($order_by) = @$order_by if ref $order_by;
+
+ $order_by =~ s/\s+ ( ASC|DESC ) \s* $//ix;
+ my $direction = lc ($1 || 'asc');
+
+ my ($unq_sort_col) = $order_by =~ /(?:^|\.)([^\.]+)$/;
+
+ my $inf = $root_rsrc->storage->_resolve_column_info (
+ $rs_attrs->{from}, [$order_by, $unq_sort_col]
+ );
+
+ my $ord_colinfo = $inf->{$order_by} || croak "Unable to determine source of order-criteria '$order_by'";
+
+ if ($ord_colinfo->{-result_source}->name ne $root_tbl_name) {
+ croak "Generic Subquery Limit order criteria can be only based on the root-source '"
+ . $root_rsrc->source_name . "' (aliased as '$rs_attrs->{alias}')";
+ }
+
+ # make sure order column is qualified
+ $order_by = "$rs_attrs->{alias}.$order_by"
+ unless $order_by =~ /^$rs_attrs->{alias}\./;
+
+ my $is_u;
+ my $ucs = { $root_rsrc->unique_constraints };
+ for (values %$ucs ) {
+ if (@$_ == 1 && "$rs_attrs->{alias}.$_->[0]" eq $order_by) {
+ $is_u++;
+ last;
+ }
+ }
+ croak "Generic Subquery Limit order criteria column '$order_by' must be unique (no unique constraint found)"
+ unless $is_u;
+
+ my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ($rs_attrs);
+
+ my $cmp_op = $direction eq 'desc' ? '>' : '<';
+ my $count_tbl_alias = 'rownum__emulation';
+
+ my $order_sql = $self->_order_by (delete $rs_attrs->{order_by});
+ my $group_having_sql = $self->_parse_rs_attrs($rs_attrs);
+
+ # add the order supplement (if any) as this is what will be used for the outer WHERE
+ $in_sel .= ", $_" for keys %{$extra_order_sel||{}};
+
+ $sql = sprintf (<<EOS,
+SELECT $out_sel
+ FROM (
+ SELECT $in_sel ${sql}${group_having_sql}
+ ) %s
+WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) %s
+$order_sql
+EOS
+ ( map { $self->_quote ($_) } (
+ $rs_attrs->{alias},
+ $root_tbl_name,
+ $count_tbl_alias,
+ "$count_tbl_alias.$unq_sort_col",
+ $order_by,
+ )),
+ $offset
+ ? sprintf ('BETWEEN %u AND %u', $offset, $offset + $rows - 1)
+ : sprintf ('< %u', $rows )
+ ,
+ );
+
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
+ return $sql;
+}
+
+
+# !!! THIS IS ALSO HORRIFIC !!! /me ashamed
+#
+# Generates inner/outer select lists for various limit dialects
+# which result in one or more subqueries (e.g. RNO, Top, RowNum)
+# Any non-root-table columns need to have their table qualifier
+# turned into a column alias (otherwise names in subqueries clash
+# and/or lose their source table)
+#
+# Returns inner/outer strings of SQL QUOTED selectors with aliases
+# (to be used in whatever select statement), and an alias index hashref
+# of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used for string-subst
+# higher up).
+# If an order_by is supplied, the inner select needs to bring out columns
+# used in implicit (non-selected) orders, and the order condition itself
+# needs to be realiased to the proper names in the outer query. Thus we
+# also return a hashref (order doesn't matter) of QUOTED EXTRA-SEL =>
+# QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
+# exist in the original select list
+
+sub _subqueried_limit_attrs {
+ my ($self, $rs_attrs) = @_;
+
+ croak 'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
+ unless ref ($rs_attrs) eq 'HASH';
+
+ my ($re_sep, $re_alias) = map { quotemeta $_ } (
+ $self->name_sep || '.',
+ $rs_attrs->{alias},
+ );
+
+ # correlate select and as, build selection index
+ my (@sel, $in_sel_index);
+ for my $i (0 .. $#{$rs_attrs->{select}}) {
+
+ my $s = $rs_attrs->{select}[$i];
+ my $sql_sel = $self->_recurse_fields ($s);
+ my $sql_alias = (ref $s) eq 'HASH' ? $s->{-as} : undef;
+
+
+ push @sel, {
+ sql => $sql_sel,
+ unquoted_sql => do { local $self->{quote_char}; $self->_recurse_fields ($s) },
+ as =>
+ $sql_alias
+ ||
+ $rs_attrs->{as}[$i]
+ ||
+ croak "Select argument $i ($s) without corresponding 'as'"
+ ,
+ };
+
+ $in_sel_index->{$sql_sel}++;
+ $in_sel_index->{$self->_quote ($sql_alias)}++ if $sql_alias;
+
+ # record unqualified versions too, so we do not have
+ # to reselect the same column twice (in qualified and
+ # unqualified form)
+ if (! ref $s && $sql_sel =~ / $re_sep (.+) $/x) {
+ $in_sel_index->{$1}++;
+ }
+ }
+
+
+ # re-alias and remove any name separators from aliases,
+ # unless we are dealing with the current source alias
+ # (which will transcend the subqueries as it is necessary
+ # for possible further chaining)
+ my (@in_sel, @out_sel, %renamed);
+ for my $node (@sel) {
+ if (first { $_ =~ / (?<! ^ $re_alias ) $re_sep /x } ($node->{as}, $node->{unquoted_sql}) ) {
+ $node->{as} = $self->_unqualify_colname($node->{as});
+ my $quoted_as = $self->_quote($node->{as});
+ push @in_sel, sprintf '%s AS %s', $node->{sql}, $quoted_as;
+ push @out_sel, $quoted_as;
+ $renamed{$node->{sql}} = $quoted_as;
+ }
+ else {
+ push @in_sel, $node->{sql};
+ push @out_sel, $self->_quote ($node->{as});
+ }
+ }
+
+ # see if the order gives us anything
+ my %extra_order_sel;
+ for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
+ # order with bind
+ $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
+ $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+
+ next if $in_sel_index->{$chunk};
+
+ $extra_order_sel{$chunk} ||= $self->_quote (
+ 'ORDER__BY__' . scalar keys %extra_order_sel
+ );
+ }
+
+ return (
+ (map { join (', ', @$_ ) } (
+ \@in_sel,
+ \@out_sel)
+ ),
+ \%renamed,
+ keys %extra_order_sel ? \%extra_order_sel : (),
+ );
+}
+
+sub _unqualify_colname {
+ my ($self, $fqcn) = @_;
+ my $re_sep = quotemeta($self->name_sep || '.');
+ $fqcn =~ s/ $re_sep /__/xg;
+ return $fqcn;
+}
+
+1;
projects / dbsrgits/DBIx-Class.git / commitdiff