use strict;
use warnings;
-use base 'DBIx::Class::Storage';
+use base qw/DBIx::Class::Storage::DBIHacks DBIx::Class::Storage/;
use mro 'c3';
use Carp::Clan qw/^DBIx::Class/;
# which will require a subquery to select the correct rows
# (i.e. joined or limited resultsets)
#
-# Genarating a single PK column subquery is trivial and supported
+# Generating a single PK column subquery is trivial and supported
# by all RDBMS. However if we have a multicolumn PK, things get ugly.
# Look at _multipk_update_delete()
sub _subq_update_delete {
return ('select', $attrs->{bind}, $ident, $bind_attrs, $select, $where, $order, @limit);
}
-#
-# This is the code producing joined subqueries like:
-# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
-#
-sub _adjust_select_args_for_complex_prefetch {
- my ($self, $from, $select, $where, $attrs) = @_;
-
- $self->throw_exception ('Nothing to prefetch... how did we get here?!')
- if not @{$attrs->{_prefetch_select}};
-
- $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]
- ];
- }
-
-
- # 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;
- }
-
- # 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);
-
-
- # decide which parts of the join will remain in either part of
- # the outer/inner query
-
- # 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})
- );
-
-
- for my $alias (keys %original_join_info) {
- my $seen_re = qr/\b $alias $sep/x;
-
- for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) {
- if ($piece =~ $seen_re) {
- $restrict_aliases->{$alias} = 1;
- }
- }
-
- if ($non_prefetch_select_sql =~ $seen_re) {
- $select_aliases->{$alias} = 1;
- }
-
- if ($prefetch_select_sql =~ $seen_re) {
- $prefetch_aliases->{$alias} = 1;
- }
-
- }
- }
-
- # 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)
- );
- }
-
- # 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} || [] });
- }
- }
-
- # 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}};
- }
-
- # 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 $alias (keys %inner_joins) {
-
- # the dot comes from some weirdness in collapse
- # remove after the rewrite
- if ($attrs->{collapse}{".$alias"}) {
- $inner_attrs->{group_by} ||= $inner_select;
- last;
- }
- }
- }
-
- # 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,
- );
-
- my $subq_joinspec = {
- -alias => $attrs->{alias},
- -source_handle => $inner_from[0]{-source_handle},
- $attrs->{alias} => $subq,
- };
-
- # Generate the outer from - this is relatively easy (really just replace
- # the join slot with the subquery), with a major caveat - we can not
- # join anything that is non-selecting (not part of the prefetch), but at
- # the same time is a multi-type relationship, as it will explode the result.
- #
- # There are two possibilities here
- # - either the join is non-restricting, in which case we simply throw it away
- # - 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
- 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;
- }
- }
-
- # see what's left - throw away if not selecting/restricting
- # also throw in a group_by if restricting to guard against
- # cross-join explosions
- #
- while (my $j = shift @$from) {
- my $alias = $j->[0]{-alias};
-
- if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) {
- push @outer_from, $j;
- }
- elsif ($restrict_aliases->{$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;
- # }
- }
- }
-
- # demote the outer_from head
- $outer_from[0] = $outer_from[0][0];
-
- # 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
- # then if where conditions apply to the *right* side of the prefetch, you may have
- # to both filter the inner select (e.g. to apply a limit) and then have to re-filter
- # the outer select to exclude joins you didin't want in the first place
- #
- # OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
- return (\@outer_from, $outer_select, $where, $outer_attrs);
-}
-
-sub _resolve_ident_sources {
- my ($self, $ident) = @_;
-
- my $alias2source = {};
- my $rs_alias;
-
- # 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") ) {
- # this is compat mode for insert/update/delete which do not deal with aliases
- $alias2source->{me} = $ident;
- $rs_alias = 'me';
- }
- elsif (ref $ident eq 'ARRAY') {
-
- for (@$ident) {
- my $tabinfo;
- if (ref $_ eq 'HASH') {
- $tabinfo = $_;
- $rs_alias = $tabinfo->{-alias};
- }
- if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
- $tabinfo = $_->[0];
- }
-
- $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve
- if ($tabinfo->{-source_handle});
- }
- }
-
- return ($alias2source, $rs_alias);
-}
-
-# Takes $ident, \@column_names
-#
-# 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);
-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);
-
- # compile a global list of column names, to be able to properly
- # disambiguate unqualified column names (if at all possible)
- for my $alias (keys %$alias2src) {
- my $rsrc = $alias2src->{$alias};
- for my $colname ($rsrc->columns) {
- push @{$seen_cols{$colname}}, $alias;
- }
- }
-
- COLUMN:
- foreach my $col (@$colnames) {
- my ($alias, $colname) = $col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x;
-
- unless ($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;
- }
- }
-
- my $rsrc = $alias2src->{$alias};
- $return{$col} = $rsrc && {
- %{$rsrc->column_info($colname)},
- -result_source => $rsrc,
- -source_alias => $alias,
- };
- }
-
- return \%return;
-}
-
# Returns a counting SELECT for a simple count
# query. Abstracted so that a storage could override
# this to { count => 'firstcol' } or whatever makes
projects / dbsrgits/DBIx-Class.git / blobdiff