my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
-IMPORTANT: If called on an object, proxies to new_result instead so
+=over
+
+=item WARNING
+
+If called on an object, proxies to L</new_result> instead, so
my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
-will return a CD object, not a ResultSet.
+will return a CD object, not a ResultSet, and is equivalent to:
+
+ my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
+
+Please also keep in mind that many internals call C<new_result> directly,
+so overloading this method with the idea of intercepting new result object
+creation B<will not work>. See also warning pertaining to L</create>.
+
+=back
=cut
my $attrs = { %{$self->_resolved_attrs} };
- # "needs" is a strong word here - if the subquery is part of an IN clause - no point of
- # even adding the group_by. It will really be used only when composing a poor-man's
- # multicolumn-IN equivalent OR set
- my $needs_group_by_subq = defined $attrs->{group_by};
+ my $existing_group_by = delete $attrs->{group_by};
+ my $needs_subq = defined $existing_group_by;
+
+ # simplify the joinmap and maybe decide if a subquery is necessary
+ my $relation_classifications = {};
- # simplify the joinmap and maybe decide if a grouping (and thus subquery) is necessary
- my $relation_classifications;
if (ref($attrs->{from}) eq 'ARRAY') {
- $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $cond, $attrs);
+ # if we already know we need a subq, no point of classifying relations
+ if (!$needs_subq and @{$attrs->{from}} > 1) {
+ $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $cond, $attrs);
- $relation_classifications = $storage->_resolve_aliastypes_from_select_args (
- [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
- $attrs->{select},
- $cond,
- $attrs
- ) unless $needs_group_by_subq; # we already know we need a group, no point of resolving them
+ $relation_classifications = $storage->_resolve_aliastypes_from_select_args (
+ [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
+ $attrs->{select},
+ $cond,
+ $attrs
+ );
+ }
}
else {
- $needs_group_by_subq ||= 1; # if {from} is unparseable assume the worst
+ $needs_subq ||= 1; # if {from} is unparseable assume the worst
}
- $needs_group_by_subq ||= exists $relation_classifications->{multiplying};
-
- # if no subquery - life is easy-ish
- unless (
- $needs_group_by_subq
- or
- keys %$relation_classifications # if any joins at all - need to wrap a subq
- or
- $self->_has_resolved_attr(qw/rows offset/) # limits call for a subq
+ # do we need anything like a subquery?
+ if (
+ ! $needs_subq
+ and
+ ! keys %{ $relation_classifications->{restricting} || {} }
+ and
+ ! $self->_has_resolved_attr(qw/rows offset/) # limits call for a subq
) {
# Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
# a condition containing 'me' or other table prefixes will not work
- # at all. What this code tries to do (badly) is to generate a condition
- # with the qualifiers removed, by exploiting the quote mechanism of sqla
- #
- # this is atrocious and should be replaced by normal sqla introspection
- # one sunny day
- my ($sql, @bind) = do {
+ # at all. Tell SQLMaker to dequalify idents via a gross hack.
+ my $cond = do {
my $sqla = $rsrc->storage->sql_maker;
local $sqla->{_dequalify_idents} = 1;
- $sqla->_recurse_where($self->{cond});
- } if $self->{cond};
-
+ \[ $sqla->_recurse_where($self->{cond}) ];
+ };
return $rsrc->storage->$op(
$rsrc,
$op eq 'update' ? $values : (),
- $self->{cond} ? \[$sql, @bind] : (),
+ $cond,
);
}
$rsrc->source_name,
)
);
- my $existing_group_by = delete $attrs->{group_by};
# make a new $rs selecting only the PKs (that's all we really need for the subq)
delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_selector_range as/;
);
}
else {
+
# if all else fails - get all primary keys and operate over a ORed set
# wrap in a transaction for consistency
# this is where the group_by starts to matter
- my $subq_group_by;
- if ($needs_group_by_subq) {
- $subq_group_by = $attrs->{columns};
-
+ if (
+ $existing_group_by
+ or
+ keys %{ $relation_classifications->{multiplying} || {} }
+ ) {
# make sure if there is a supplied group_by it matches the columns compiled above
# perfectly. Anything else can not be sanely executed on most databases so croak
# right then and there
if (
join ("\x00", sort @current_group_by)
ne
- join ("\x00", sort @$subq_group_by )
+ join ("\x00", sort @{$attrs->{columns}} )
) {
$self->throw_exception (
"You have just attempted a $op operation on a resultset which does group_by"
);
}
}
+
+ $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
}
my $guard = $storage->txn_scope_guard;
my @op_condition;
- for my $row ($subrs->search({}, { group_by => $subq_group_by })->cursor->all) {
+ for my $row ($subrs->cursor->all) {
push @op_condition, { map
{ $idcols->[$_] => $row->[$_] }
(0 .. $#$idcols)
sub new_result {
my ($self, $values) = @_;
- $self->throw_exception( "new_result needs a hash" )
+
+ $self->throw_exception( "new_result takes only one argument - a hashref of values" )
+ if @_ > 2;
+
+ $self->throw_exception( "new_result expects a hashref" )
unless (ref $values eq 'HASH');
my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
with an arbitrary depth and width, as long as the relationships actually
exists and the correct column data has been supplied.
-
Instead of hashrefs of plain related data (key/value pairs), you may
also pass new or inserted objects. New objects (not inserted yet, see
L</new>), will be inserted into their appropriate tables.
lot of the internals simply never call it, so your override will be
bypassed more often than not. Override either L<new|DBIx::Class::Row/new>
or L<insert|DBIx::Class::Row/insert> depending on how early in the
-L</create> process you need to intervene.
+L</create> process you need to intervene. See also warning pertaining to
+L</new>.
=back
See also L</find> and L</update_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
+If you need to know if an existing row was found or a new one created use
+L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
+to call L<DBIx::Class::Row/insert> to save the newly created row to the
+database!
+
+ my $cd = $schema->resultset('CD')->find_or_new({
+ cdid => 5,
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ year => 2005,
+ });
+
+ if( !$cd->in_storage ) {
+ # do some stuff
+ $cd->insert;
+ }
+
=cut
sub find_or_create {
See also L</find> and L</find_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
+If you need to know if an existing row was updated or a new one created use
+L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
+to call L<DBIx::Class::Row/insert> to save the newly created row to the
+database!
+
=cut
sub update_or_create {
my $me = $self->current_source_alias;
- return $self->search(
+ return $self->search({
"$me.modified" => $user->id,
- );
+ });
}
=cut
$attrs->{_collapse_order_by} = \@$prefetch_ordering;
}
-
# if both page and offset are specified, produce a combined offset
# even though it doesn't make much sense, this is what pre 081xx has
# been doing
If you want to fetch related objects from other tables as well, see C<prefetch>
below.
+ NOTE: An internal join-chain pruner will discard certain joins while
+ constructing the actual SQL query, as long as the joins in question do not
+ affect the retrieved result. This for example includes 1:1 left joins
+ that are not part of the restriction specification (WHERE/HAVING) nor are
+ a part of the query selection.
+
For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
=head2 prefetch
Specifies the (zero-based) row number for the first row to be returned, or the
of the first row of the first page if paging is used.
+=head2 software_limit
+
+=over 4
+
+=item Value: (0 | 1)
+
+=back
+
+When combined with L</rows> and/or L</offset> the generated SQL will not
+include any limit dialect stanzas. Instead the entire result will be selected
+as if no limits were specified, and DBIC will perform the limit locally, by
+artificially advancing and finishing the resulting L</cursor>.
+
+This is the recommended way of performing resultset limiting when no sane RDBMS
+implementation is available (e.g.
+L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
+L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
+
=head2 group_by
=over 4
Adds to the WHERE clause.
# only return rows WHERE deleted IS NULL for all searches
- __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
+ __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
Can be overridden by passing C<< { where => undef } >> as an attribute
to a resultset.
=over 4
-=item Value: ( 'update' | 'shared' )
+=item Value: ( 'update' | 'shared' | \$scalar )
=back
Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
-... FOR SHARED.
+... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
+query.
=cut
projects / dbsrgits/DBIx-Class.git / blobdiff