-package DBIx::Class::Storage::DBIHacks;
+package #hide from PAUSE
+ DBIx::Class::Storage::DBIHacks;
#
# This module contains code that should never have seen the light of day,
# does not belong in the Storage, or is otherwise unfit for public
-# display. The arrival of SQLA2 should immediately oboslete 90% of this
+# display. The arrival of SQLA2 should immediately obsolete 90% of this
#
use strict;
use base 'DBIx::Class::Storage';
use mro 'c3';
-use Carp::Clan qw/^DBIx::Class/;
+use List::Util 'first';
+use Scalar::Util 'blessed';
+use Sub::Name 'subname';
+use namespace::clean;
+
+#
+# This code will remove non-selecting/non-restricting joins from
+# {from} specs, aiding the RDBMS query optimizer
+#
+sub _prune_unused_joins {
+ my $self = shift;
+ my ($from, $select, $where, $attrs) = @_;
+
+ return $from unless $self->_use_join_optimizer;
+
+ if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') {
+ return $from; # only standard {from} specs are supported
+ }
+
+ my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_);
+
+ # a grouped set will not be affected by amount of rows. Thus any
+ # {multiplying} joins can go
+ delete $aliastypes->{multiplying} if $attrs->{group_by};
+
+ my @newfrom = $from->[0]; # FROM head is always present
+
+ my %need_joins;
+ for (values %$aliastypes) {
+ # add all requested aliases
+ $need_joins{$_} = 1 for keys %$_;
+
+ # add all their parents (as per joinpath which is an AoH { table => alias })
+ $need_joins{$_} = 1 for map { values %$_ } map { @$_ } values %$_;
+ }
+ for my $j (@{$from}[1..$#$from]) {
+ push @newfrom, $j if (
+ (! $j->[0]{-alias}) # legacy crap
+ ||
+ $need_joins{$j->[0]{-alias}}
+ );
+ }
+
+ return \@newfrom;
+}
#
# This is the code producing joined subqueries like:
-# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
+# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
#
sub _adjust_select_args_for_complex_prefetch {
my ($self, $from, $select, $where, $attrs) = @_;
$self->throw_exception ('Nothing to prefetch... how did we get here?!')
- if not @{$attrs->{_prefetch_select}};
+ if not @{$attrs->{_prefetch_selector_range}};
$self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY');
-
# generate inner/outer attribute lists, remove stuff that doesn't apply
my $outer_attrs = { %$attrs };
delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/;
my $inner_attrs = { %$attrs };
- delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/;
-
-
- # bring over all non-collapse-induced order_by into the inner query (if any)
- # the outer one will have to keep them all
- delete $inner_attrs->{order_by};
- if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) {
- $inner_attrs->{order_by} = [
- @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1]
- ];
- }
+ delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range select as/;
+ # if the user did not request it, there is no point using it inside
+ delete $inner_attrs->{order_by} if delete $inner_attrs->{_order_is_artificial};
# generate the inner/outer select lists
# for inside we consider only stuff *not* brought in by the prefetch
# on the outside we substitute any function for its alias
my $outer_select = [ @$select ];
my $inner_select = [];
- for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) {
- my $sel = $outer_select->[$i];
-
- if (ref $sel eq 'HASH' ) {
- $sel->{-as} ||= $attrs->{as}[$i];
- $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") );
- }
- push @$inner_select, $sel;
- }
+ my ($root_source, $root_source_offset);
- # normalize a copy of $from, so it will be easier to work with further
- # down (i.e. promote the initial hashref to an AoH)
- $from = [ @$from ];
- $from->[0] = [ $from->[0] ];
- my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
+ for my $i (0 .. $#$from) {
+ my $node = $from->[$i];
+ my $h = (ref $node eq 'HASH') ? $node
+ : (ref $node eq 'ARRAY' and ref $node->[0] eq 'HASH') ? $node->[0]
+ : next
+ ;
+ if ( ($h->{-alias}||'') eq $attrs->{alias} and $root_source = $h->{-rsrc} ) {
+ $root_source_offset = $i;
+ last;
+ }
+ }
- # decide which parts of the join will remain in either part of
- # the outer/inner query
+ $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
+ unless $root_source;
- # First we compose a list of which aliases are used in restrictions
- # (i.e. conditions/order/grouping/etc). Since we do not have
- # introspectable SQLA, we fall back to ugly scanning of raw SQL for
- # WHERE, and for pieces of ORDER BY in order to determine which aliases
- # need to appear in the resulting sql.
- # It may not be very efficient, but it's a reasonable stop-gap
- # Also unqualified column names will not be considered, but more often
- # than not this is actually ok
- #
- # In the same loop we enumerate part of the selection aliases, as
- # it requires the same sqla hack for the time being
- my ($restrict_aliases, $select_aliases, $prefetch_aliases);
- {
- # produce stuff unquoted, so it can be scanned
- my $sql_maker = $self->sql_maker;
- local $sql_maker->{quote_char};
- my $sep = $self->_sql_maker_opts->{name_sep} || '.';
- $sep = "\Q$sep\E";
-
- my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select);
- my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select});
- my $where_sql = $sql_maker->where ($where);
- my $group_by_sql = $sql_maker->_order_by({
- map { $_ => $inner_attrs->{$_} } qw/group_by having/
- });
- my @non_prefetch_order_by_chunks = (map
- { ref $_ ? $_->[0] : $_ }
- $sql_maker->_order_by_chunks ($inner_attrs->{order_by})
- );
+ # use the heavy duty resolver to take care of aliased/nonaliased naming
+ my $colinfo = $self->_resolve_column_info($from);
+ my $selected_root_columns;
+ my ($p_start, $p_end) = @{$outer_attrs->{_prefetch_selector_range}};
+ for my $i (0 .. $p_start - 1, $p_end + 1 .. $#$outer_select) {
+ my $sel = $outer_select->[$i];
- for my $alias (keys %original_join_info) {
- my $seen_re = qr/\b $alias $sep/x;
+ if (ref $sel eq 'HASH' ) {
+ $sel->{-as} ||= $attrs->{as}[$i];
+ $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") );
+ }
+ elsif (! ref $sel and my $ci = $colinfo->{$sel}) {
+ $selected_root_columns->{$ci->{-colname}} = 1;
+ }
- for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) {
- if ($piece =~ $seen_re) {
- $restrict_aliases->{$alias} = 1;
- }
- }
+ push @$inner_select, $sel;
- if ($non_prefetch_select_sql =~ $seen_re) {
- $select_aliases->{$alias} = 1;
- }
+ push @{$inner_attrs->{as}}, $attrs->{as}[$i];
+ }
- if ($prefetch_select_sql =~ $seen_re) {
- $prefetch_aliases->{$alias} = 1;
+ # We will need to fetch all native columns in the inner subquery, which may be a part
+ # of an *outer* join condition. We can not just fetch everything because a potential
+ # has_many restricting join collapse *will not work* on heavy data types.
+ # Time for more horrible SQL parsing, aughhhh
+
+ # MASSIVE FIXME - in fact when we are fully transitioned to DQ and the support is
+ # is sane - we will need to trim the select list to *only* fetch stuff that is
+ # necessary to build joins. In the current implementation if I am selecting a blob
+ # and the group_by kicks in - we are fucked, and all the user can do is not select
+ # that column. This is silly!
+
+ my $retardo_sqla_cache = {};
+ for my $cond ( map { $_->[1] } @{$from}[$root_source_offset + 1 .. $#$from] ) {
+ for my $col (@{$self->_extract_condition_columns($cond, $retardo_sqla_cache)}) {
+ my $ci = $colinfo->{$col};
+ if (
+ $ci
+ and
+ $ci->{-source_alias} eq $attrs->{alias}
+ and
+ ! $selected_root_columns->{$ci->{-colname}}++
+ ) {
+ # adding it to both to keep limits not supporting dark selectors happy
+ push @$inner_select, $ci->{-fq_colname};
+ push @{$inner_attrs->{as}}, $ci->{-fq_colname};
}
-
}
}
- # Add any non-left joins to the restriction list (such joins are indeed restrictions)
- for my $j (values %original_join_info) {
- my $alias = $j->{-alias} or next;
- $restrict_aliases->{$alias} = 1 if (
- (not $j->{-join_type})
- or
- ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
- );
- }
+ # construct the inner $from and lock it in a subquery
+ # we need to prune first, because this will determine if we need a group_by below
+ # the fake group_by is so that the pruner throws away all non-selecting, non-restricting
+ # multijoins (since we def. do not care about those inside the subquery)
- # mark all join parents as mentioned
- # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
- for my $collection ($restrict_aliases, $select_aliases) {
- for my $alias (keys %$collection) {
- $collection->{$_} = 1
- for (@{ $original_join_info{$alias}{-join_path} || [] });
- }
- }
+ my $inner_subq = do {
- # construct the inner $from for the subquery
- my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) );
- my @inner_from;
- for my $j (@$from) {
- push @inner_from, $j if $inner_joins{$j->[0]{-alias}};
- }
+ # must use it here regardless of user requests
+ local $self->{_use_join_optimizer} = 1;
- # if a multi-type join was needed in the subquery ("multi" is indicated by
- # presence in {collapse}) - add a group_by to simulate the collapse in the subq
- unless ($inner_attrs->{group_by}) {
- for my $alias (keys %inner_joins) {
+ my $inner_from = $self->_prune_unused_joins ($from, $inner_select, $where, {
+ group_by => ['dummy'], %$inner_attrs,
+ });
- # the dot comes from some weirdness in collapse
- # remove after the rewrite
- if ($attrs->{collapse}{".$alias"}) {
- $inner_attrs->{group_by} ||= $inner_select;
- last;
- }
+ my $inner_aliastypes =
+ $self->_resolve_aliastypes_from_select_args( $inner_from, $inner_select, $where, $inner_attrs );
+
+ # we need to simulate collapse in the subq if a multiplying join is pulled
+ # by being a non-selecting restrictor
+ if (
+ ! $inner_attrs->{group_by}
+ and
+ first {
+ $inner_aliastypes->{restricting}{$_}
+ and
+ ! $inner_aliastypes->{selecting}{$_}
+ } ( keys %{$inner_aliastypes->{multiplying}||{}} )
+ ) {
+ my $unprocessed_order_chunks;
+ ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection (
+ $inner_from, $inner_select, $inner_attrs->{order_by}
+ );
+
+ $self->throw_exception (
+ 'A required group_by clause could not be constructed automatically due to a complex '
+ . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+ . 'group_by by hand'
+ ) if $unprocessed_order_chunks;
}
- }
-
- # demote the inner_from head
- $inner_from[0] = $inner_from[0][0];
- # generate the subquery
- my $subq = $self->_select_args_to_query (
- \@inner_from,
- $inner_select,
- $where,
- $inner_attrs,
- );
+ # we already optimized $inner_from above
+ local $self->{_use_join_optimizer} = 0;
- my $subq_joinspec = {
- -alias => $attrs->{alias},
- -source_handle => $inner_from[0]{-source_handle},
- $attrs->{alias} => $subq,
+ # generate the subquery
+ $self->_select_args_to_query (
+ $inner_from,
+ $inner_select,
+ $where,
+ $inner_attrs,
+ );
};
# Generate the outer from - this is relatively easy (really just replace
# - it is part of the restrictions, in which case we need to collapse the outer
# result by tackling yet another group_by to the outside of the query
- # so first generate the outer_from, up to the substitution point
+ # work on a shallow copy
+ $from = [ @$from ];
+
my @outer_from;
- while (my $j = shift @$from) {
- if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap
- push @outer_from, [
- $subq_joinspec,
- @{$j}[1 .. $#$j],
- ];
- last; # we'll take care of what's left in $from below
- }
- else {
- push @outer_from, $j;
- }
+
+ # we may not be the head
+ if ($root_source_offset) {
+ # first generate the outer_from, up to the substitution point
+ @outer_from = splice @$from, 0, $root_source_offset;
+
+ my $root_node = shift @$from;
+
+ push @outer_from, [
+ {
+ -alias => $attrs->{alias},
+ -rsrc => $root_node->[0]{-rsrc},
+ $attrs->{alias} => $inner_subq,
+ },
+ @{$root_node}[1 .. $#$root_node],
+ ];
+ }
+ else {
+ my $root_node = shift @$from;
+
+ @outer_from = {
+ -alias => $attrs->{alias},
+ -rsrc => $root_node->{-rsrc},
+ $attrs->{alias} => $inner_subq,
+ };
}
+ # scan the *remaining* from spec against different attributes, and see which joins are needed
+ # in what role
+ my $outer_aliastypes =
+ $self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs );
+
+ # unroll parents
+ my ($outer_select_chain, $outer_restrict_chain) = map { +{
+ map { $_ => 1 } map { values %$_} map { @$_ } values %{ $outer_aliastypes->{$_} || {} }
+ } } qw/selecting restricting/;
+
# see what's left - throw away if not selecting/restricting
- # also throw in a group_by if restricting to guard against
- # cross-join explosions
- #
+ # also throw in a group_by if a non-selecting multiplier,
+ # to guard against cross-join explosions
+ my $need_outer_group_by;
while (my $j = shift @$from) {
my $alias = $j->[0]{-alias};
- if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) {
- push @outer_from, $j;
+ if (
+ $outer_select_chain->{$alias}
+ ) {
+ push @outer_from, $j
}
- elsif ($restrict_aliases->{$alias}) {
+ elsif ($outer_restrict_chain->{$alias}) {
push @outer_from, $j;
-
- # FIXME - this should be obviated by SQLA2, as I'll be able to
- # have restrict_inner and restrict_outer... or something to that
- # effect... I think...
-
- # FIXME2 - I can't find a clean way to determine if a particular join
- # is a multi - instead I am just treating everything as a potential
- # explosive join (ribasushi)
- #
- # if (my $handle = $j->[0]{-source_handle}) {
- # my $rsrc = $handle->resolve;
- # ... need to bail out of the following if this is not a multi,
- # as it will be much easier on the db ...
-
- $outer_attrs->{group_by} ||= $outer_select;
- # }
+ $need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0;
}
}
- # demote the outer_from head
- $outer_from[0] = $outer_from[0][0];
+ if ($need_outer_group_by and ! $outer_attrs->{group_by}) {
+
+ my $unprocessed_order_chunks;
+ ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection (
+ \@outer_from, $outer_select, $outer_attrs->{order_by}
+ );
+
+ $self->throw_exception (
+ 'A required group_by clause could not be constructed automatically due to a complex '
+ . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+ . 'group_by by hand'
+ ) if $unprocessed_order_chunks;
+
+ }
# This is totally horrific - the $where ends up in both the inner and outer query
# Unfortunately not much can be done until SQLA2 introspection arrives, and even
return (\@outer_from, $outer_select, $where, $outer_attrs);
}
+#
+# I KNOW THIS SUCKS! GET SQLA2 OUT THE DOOR SO THIS CAN DIE!
+#
+# Due to a lack of SQLA2 we fall back to crude scans of all the
+# select/where/order/group attributes, in order to determine what
+# aliases are neded to fulfill the query. This information is used
+# throughout the code to prune unnecessary JOINs from the queries
+# in an attempt to reduce the execution time.
+# Although the method is pretty horrific, the worst thing that can
+# happen is for it to fail due to some scalar SQL, which in turn will
+# result in a vocal exception.
+sub _resolve_aliastypes_from_select_args {
+ my ( $self, $from, $select, $where, $attrs ) = @_;
+
+ $self->throw_exception ('Unable to analyze custom {from}')
+ if ref $from ne 'ARRAY';
+
+ # what we will return
+ my $aliases_by_type;
+
+ # see what aliases are there to work with
+ my $alias_list;
+ for (@$from) {
+ my $j = $_;
+ $j = $j->[0] if ref $j eq 'ARRAY';
+ my $al = $j->{-alias}
+ or next;
+
+ $alias_list->{$al} = $j;
+ $aliases_by_type->{multiplying}{$al} ||= $j->{-join_path}||[] if (
+ # not array == {from} head == can't be multiplying
+ ( ref($_) eq 'ARRAY' and ! $j->{-is_single} )
+ or
+ # a parent of ours is already a multiplier
+ ( grep { $aliases_by_type->{multiplying}{$_} } @{ $j->{-join_path}||[] } )
+ );
+ }
+
+ # get a column to source/alias map (including unqualified ones)
+ my $colinfo = $self->_resolve_column_info ($from);
+
+ # set up a botched SQLA
+ my $sql_maker = $self->sql_maker;
+
+ # these are throw away results, do not pollute the bind stack
+ local $sql_maker->{select_bind};
+ local $sql_maker->{where_bind};
+ local $sql_maker->{group_bind};
+ local $sql_maker->{having_bind};
+
+ # we can't scan properly without any quoting (\b doesn't cut it
+ # everywhere), so unless there is proper quoting set - use our
+ # own weird impossible character.
+ # Also in the case of no quoting, we need to explicitly disable
+ # name_sep, otherwise sorry nasty legacy syntax like
+ # { 'count(foo.id)' => { '>' => 3 } } will stop working >:(
+ local $sql_maker->{quote_char} = $sql_maker->{quote_char};
+ local $sql_maker->{name_sep} = $sql_maker->{name_sep};
+
+ unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
+ $sql_maker->{quote_char} = ["\x00", "\xFF"];
+ # if we don't unset it we screw up retarded but unfortunately working
+ # 'MAX(foo.bar)' => { '>', 3 }
+ $sql_maker->{name_sep} = '';
+ }
+
+ my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
+
+ # generate sql chunks
+ my $to_scan = {
+ restricting => [
+ $sql_maker->_recurse_where ($where),
+ $sql_maker->_parse_rs_attrs ({
+ map { $_ => $attrs->{$_} } (qw/group_by having/)
+ }),
+ ],
+ selecting => [
+ $sql_maker->_recurse_fields ($select),
+ ( map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker) ),
+ ],
+ };
+
+ # throw away empty chunks
+ $_ = [ map { $_ || () } @$_ ] for values %$to_scan;
+
+ # first loop through all fully qualified columns and get the corresponding
+ # alias (should work even if they are in scalarrefs)
+ for my $alias (keys %$alias_list) {
+ my $al_re = qr/
+ $lquote $alias $rquote $sep
+ |
+ \b $alias \.
+ /x;
+
+ for my $type (keys %$to_scan) {
+ for my $piece (@{$to_scan->{$type}}) {
+ $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[]
+ if ($piece =~ $al_re);
+ }
+ }
+ }
+
+ # now loop through unqualified column names, and try to locate them within
+ # the chunks
+ for my $col (keys %$colinfo) {
+ next if $col =~ / \. /x; # if column is qualified it was caught by the above
+
+ my $col_re = qr/ $lquote $col $rquote /x;
+
+ for my $type (keys %$to_scan) {
+ for my $piece (@{$to_scan->{$type}}) {
+ if ($piece =~ $col_re) {
+ my $alias = $colinfo->{$col}{-source_alias};
+ $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[];
+ }
+ }
+ }
+ }
+
+ # Add any non-left joins to the restriction list (such joins are indeed restrictions)
+ for my $j (values %$alias_list) {
+ my $alias = $j->{-alias} or next;
+ $aliases_by_type->{restricting}{$alias} ||= $j->{-join_path}||[] if (
+ (not $j->{-join_type})
+ or
+ ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
+ );
+ }
+
+ return $aliases_by_type;
+}
+
+# This is the engine behind { distinct => 1 }
+sub _group_over_selection {
+ my ($self, $from, $select, $order_by) = @_;
+
+ my $rs_column_list = $self->_resolve_column_info ($from);
+
+ my (@group_by, %group_index);
+
+ # the logic is: if it is a { func => val } we assume an aggregate,
+ # otherwise if \'...' or \[...] we assume the user knows what is
+ # going on thus group over it
+ for (@$select) {
+ if (! ref($_) or ref ($_) ne 'HASH' ) {
+ push @group_by, $_;
+ $group_index{$_}++;
+ if ($rs_column_list->{$_} and $_ !~ /\./ ) {
+ # add a fully qualified version as well
+ $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++;
+ }
+ }
+ }
+
+ # add any order_by parts that are not already present in the group_by
+ # we need to be careful not to add any named functions/aggregates
+ # i.e. order_by => [ ... { count => 'foo' } ... ]
+ my @leftovers;
+ for ($self->_extract_order_criteria($order_by)) {
+ # only consider real columns (for functions the user got to do an explicit group_by)
+ if (@$_ != 1) {
+ push @leftovers, $_;
+ next;
+ }
+ my $chunk = $_->[0];
+ my $colinfo = $rs_column_list->{$chunk} or do {
+ push @leftovers, $_;
+ next;
+ };
+
+ $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./;
+ push @group_by, $chunk unless $group_index{$chunk}++;
+ }
+
+ return wantarray
+ ? (\@group_by, (@leftovers ? \@leftovers : undef) )
+ : \@group_by
+ ;
+}
+
sub _resolve_ident_sources {
my ($self, $ident) = @_;
# the reason this is so contrived is that $ident may be a {from}
# structure, specifying multiple tables to join
- if ( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) {
+ if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) {
# this is compat mode for insert/update/delete which do not deal with aliases
$alias2source->{me} = $ident;
$rs_alias = 'me';
$tabinfo = $_->[0];
}
- $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve
- if ($tabinfo->{-source_handle});
+ $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc}
+ if ($tabinfo->{-rsrc});
}
}
# returns { $column_name => \%column_info, ... }
# also note: this adds -result_source => $rsrc to the column info
#
-# usage:
-# my $col_sources = $self->_resolve_column_info($ident, @column_names);
+# If no columns_names are supplied returns info about *all* columns
+# for all sources
sub _resolve_column_info {
my ($self, $ident, $colnames) = @_;
my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident);
- my $sep = $self->_sql_maker_opts->{name_sep} || '.';
- $sep = "\Q$sep\E";
-
- my (%return, %seen_cols);
+ my (%seen_cols, @auto_colnames);
# compile a global list of column names, to be able to properly
# disambiguate unqualified column names (if at all possible)
my $rsrc = $alias2src->{$alias};
for my $colname ($rsrc->columns) {
push @{$seen_cols{$colname}}, $alias;
+ push @auto_colnames, "$alias.$colname" unless $colnames;
}
}
- COLUMN:
+ $colnames ||= [
+ @auto_colnames,
+ grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
+ ];
+
+ my (%return, $colinfos);
foreach my $col (@$colnames) {
- my ($alias, $colname) = $col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x;
+ my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
- unless ($alias) {
- # see if the column was seen exactly once (so we know which rsrc it came from)
- if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) {
- $alias = $seen_cols{$colname}[0];
- }
- else {
- next COLUMN;
- }
- }
+ # if the column was seen exactly once - we know which rsrc it came from
+ $source_alias ||= $seen_cols{$colname}[0]
+ if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
- my $rsrc = $alias2src->{$alias};
- $return{$col} = $rsrc && {
- %{$rsrc->column_info($colname)},
+ next unless $source_alias;
+
+ my $rsrc = $alias2src->{$source_alias}
+ or next;
+
+ $return{$col} = {
+ %{
+ ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname}
+ ||
+ $self->throw_exception(
+ "No such column '$colname' on source " . $rsrc->source_name
+ );
+ },
-result_source => $rsrc,
- -source_alias => $alias,
+ -source_alias => $source_alias,
+ -fq_colname => $col eq $colname ? "$source_alias.$col" : $col,
+ -colname => $colname,
};
+
+ $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname;
}
return \%return;
# the top of the stack, and if not - make sure the chain is inner-joined down
# to the root.
#
-sub _straight_join_to_node {
+sub _inner_join_to_node {
my ($self, $from, $alias) = @_;
# subqueries and other oddness are naturally not supported
# So it looks like we will have to switch some stuff around.
# local() is useless here as we will be leaving the scope
# anyway, and deep cloning is just too fucking expensive
- # So replace the first hashref in the node arrayref manually
+ # So replace the first hashref in the node arrayref manually
my @new_from = ($from->[0]);
- my $sw_idx = { map { $_ => 1 } @$switch_branch };
+ my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
for my $j (@{$from}[1 .. $#$from]) {
my $jalias = $j->[0]{-alias};
return \@new_from;
}
+# yet another atrocity: attempt to extract all columns from a
+# where condition by hooking _quote
+sub _extract_condition_columns {
+ my ($self, $cond, $sql_maker_cache) = @_;
+
+ return [] unless $cond;
+
+ my $sm = $sql_maker_cache->{condparser} ||= $self->{_sql_ident_capturer} ||= do {
+ # FIXME - replace with a Moo trait
+ my $orig_sm_class = ref $self->sql_maker;
+ my $smic_class = "${orig_sm_class}::_IdentCapture_";
+
+ unless ($smic_class->isa('SQL::Abstract')) {
+
+ no strict 'refs';
+ *{"${smic_class}::_quote"} = subname "${smic_class}::_quote" => sub {
+ my ($self, $ident) = @_;
+ if (ref $ident eq 'SCALAR') {
+ $ident = $$ident;
+ my $storage_quotes = $self->sql_quote_char || '"';
+ my ($ql, $qr) = map
+ { quotemeta $_ }
+ (ref $storage_quotes eq 'ARRAY' ? @$storage_quotes : ($storage_quotes) x 2 )
+ ;
+
+ while ($ident =~ /
+ $ql (\w+) $qr
+ |
+ ([\w\.]+)
+ /xg) {
+ $self->{_captured_idents}{$1||$2}++;
+ }
+ }
+ else {
+ $self->{_captured_idents}{$ident}++;
+ }
+ return $ident;
+ };
+
+ *{"${smic_class}::_get_captured_idents"} = subname "${smic_class}::_get_captures" => sub {
+ (delete shift->{_captured_idents}) || {};
+ };
+
+ $self->inject_base ($smic_class, $orig_sm_class);
+
+ }
+
+ $smic_class->new();
+ };
+
+ $sm->_recurse_where($cond);
+
+ return [ sort keys %{$sm->_get_captured_idents} ];
+}
+
+sub _extract_order_criteria {
+ my ($self, $order_by, $sql_maker) = @_;
+
+ my $parser = sub {
+ my ($sql_maker, $order_by) = @_;
+
+ return scalar $sql_maker->_order_by_chunks ($order_by)
+ unless wantarray;
+
+ my @chunks;
+ for ($sql_maker->_order_by_chunks ($order_by) ) {
+ my $chunk = ref $_ ? $_ : [ $_ ];
+ $chunk->[0] =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+ push @chunks, $chunk;
+ }
+
+ return @chunks;
+ };
+
+ if ($sql_maker) {
+ return $parser->($sql_maker, $order_by);
+ }
+ else {
+ $sql_maker = $self->sql_maker;
+ local $sql_maker->{quote_char};
+ return $parser->($sql_maker, $order_by);
+ }
+}
+
+sub _order_by_is_stable {
+ my ($self, $ident, $order_by, $where) = @_;
+
+ my $colinfo = $self->_resolve_column_info($ident, [
+ (map { $_->[0] } $self->_extract_order_criteria($order_by)),
+ $where ? @{$self->_extract_fixed_condition_columns($where)} :(),
+ ]);
+
+ return undef unless keys %$colinfo;
+
+ my $cols_per_src;
+ $cols_per_src->{$_->{-source_alias}}{$_->{-colname}} = $_ for values %$colinfo;
+
+ for (values %$cols_per_src) {
+ my $src = (values %$_)[0]->{-result_source};
+ return 1 if $src->_identifying_column_set($_);
+ }
+
+ return undef;
+}
+
+# returns an arrayref of column names which *definitely* have som
+# sort of non-nullable equality requested in the given condition
+# specification. This is used to figure out if a resultset is
+# constrained to a column which is part of a unique constraint,
+# which in turn allows us to better predict how ordering will behave
+# etc.
+#
+# this is a rudimentary, incomplete, and error-prone extractor
+# however this is OK - it is conservative, and if we can not find
+# something that is in fact there - the stack will recover gracefully
+# Also - DQ and the mst it rode in on will save us all RSN!!!
+sub _extract_fixed_condition_columns {
+ my ($self, $where, $nested) = @_;
+
+ return unless ref $where eq 'HASH';
+
+ my @cols;
+ for my $lhs (keys %$where) {
+ if ($lhs =~ /^\-and$/i) {
+ push @cols, ref $where->{$lhs} eq 'ARRAY'
+ ? ( map { $self->_extract_fixed_condition_columns($_, 1) } @{$where->{$lhs}} )
+ : $self->_extract_fixed_condition_columns($where->{$lhs}, 1)
+ ;
+ }
+ elsif ($lhs !~ /^\-/) {
+ my $val = $where->{$lhs};
+
+ push @cols, $lhs if (defined $val and (
+ ! ref $val
+ or
+ (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='})
+ ));
+ }
+ }
+ return $nested ? @cols : \@cols;
+}
+
1;