# 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;