use strict;
use warnings;
-use base qw/DBIx::Class::Storage::DBI::AmbiguousGlob DBIx::Class::Storage::DBI/;
+use base qw/DBIx::Class::Storage::DBI::UniqueIdentifier/;
use mro 'c3';
use List::Util();
}
}
-# support MSSQL GUID column types
-
sub insert {
my $self = shift;
my ($source, $to_insert) = @_;
my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] );
- my %guid_cols;
- my @pk_cols = $source->primary_columns;
- my %pk_cols;
- @pk_cols{@pk_cols} = ();
-
- my @pk_guids = grep {
- $source->column_info($_)->{data_type}
- &&
- $source->column_info($_)->{data_type} =~ /^uniqueidentifier/i
- } @pk_cols;
-
- my @auto_guids = grep {
- $source->column_info($_)->{data_type}
- &&
- $source->column_info($_)->{data_type} =~ /^uniqueidentifier/i
- &&
- $source->column_info($_)->{auto_nextval}
- } grep { not exists $pk_cols{$_} } $source->columns;
-
- my @get_guids_for =
- grep { not exists $to_insert->{$_} } (@pk_guids, @auto_guids);
-
- my $updated_cols = {};
-
- for my $guid_col (@get_guids_for) {
- my ($new_guid) = $self->_get_dbh->selectrow_array('SELECT NEWID()');
- $updated_cols->{$guid_col} = $to_insert->{$guid_col} = $new_guid;
- }
-
my $is_identity_insert = (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) )
? 1
: 0;
$self->_set_identity_insert ($source->name);
}
- $updated_cols = { %$updated_cols, %{ $self->next::method(@_) } };
+ my $updated_cols = $self->next::method(@_);
if ($is_identity_insert) {
$self->_unset_identity_insert ($source->name);
}
-
return $updated_cols;
}
# see if this is an ordered subquery
my $attrs = $_[3];
- if ( scalar $self->sql_maker->_order_by_chunks ($attrs->{order_by}) ) {
+ if ( scalar $self->_parse_order_by ($attrs->{order_by}) ) {
+ $self->throw_exception(
+ 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL
+ ') unless $attrs->{unsafe_subselect_ok};
my $max = 2 ** 32;
$sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi;
}
sub sqlt_type { 'SQLServer' }
-sub _get_mssql_version {
- my $self = shift;
-
- my $data = $self->_get_dbh->selectrow_hashref('xp_msver ProductVersion');
-
- if ($data->{Character_Value} =~ /^(\d+)\./) {
- return $1;
- } else {
- $self->throw_exception(q{Your ProductVersion's Character_Value is missing or malformed!});
- }
-}
-
sub sql_maker {
my $self = shift;
unless ($self->_sql_maker) {
unless ($self->{_sql_maker_opts}{limit_dialect}) {
- my $version = eval { $self->_get_mssql_version; } || 0;
+
+ my $version = $self->_server_info->{normalized_dbms_version} || 0;
$self->{_sql_maker_opts} = {
limit_dialect => ($version >= 9 ? 'RowNumberOver' : 'Top'),
return $self->_sql_maker;
}
+sub _ping {
+ my $self = shift;
+
+ my $dbh = $self->_dbh or return 0;
+
+ local $dbh->{RaiseError} = 1;
+ local $dbh->{PrintError} = 0;
+
+ eval {
+ $dbh->do('select 1');
+ };
+
+ return $@ ? 0 : 1;
+}
+
1;
=head1 NAME
C<db_ddladmin> privilege, which is normally not included in the standard
write-permissions.
+=head2 Ordered Subselects
+
+If you attempted the following query (among many others) in Microsoft SQL
+Server
+
+ $rs->search ({}, {
+ prefetch => 'relation',
+ rows => 2,
+ offset => 3,
+ });
+
+You may be surprised to receive an exception. The reason for this is a quirk
+in the MSSQL engine itself, and sadly doesn't have a sensible workaround due
+to the way DBIC is built. DBIC can do truly wonderful things with the aid of
+subselects, and does so automatically when necessary. The list of situations
+when a subselect is necessary is long and still changes often, so it can not
+be exhaustively enumerated here. The general rule of thumb is a joined
+L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group
+applied to the left part of the join.
+
+In its "pursuit of standards" Microsft SQL Server goes to great lengths to
+forbid the use of ordered subselects. This breaks a very useful group of
+searches like "Give me things number 4 to 6 (ordered by name), and prefetch
+all their relations, no matter how many". While there is a hack which fools
+the syntax checker, the optimizer may B<still elect to break the subselect>.
+Testing has determined that while such breakage does occur (the test suite
+contains an explicit test which demonstrates the problem), it is relative
+rare. The benefits of ordered subselects are on the other hand too great to be
+outright disabled for MSSQL.
+
+Thus compromise between usability and perfection is the MSSQL-specific
+L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>.
+It is deliberately not possible to set this on the Storage level, as the user
+should inspect (and preferably regression-test) the return of every such
+ResultSet individually. The example above would work if written like:
+
+ $rs->search ({}, {
+ unsafe_subselect_ok => 1,
+ prefetch => 'relation',
+ rows => 2,
+ offset => 3,
+ });
+
+If it is possible to rewrite the search() in a way that will avoid the need
+for this flag - you are urged to do so. If DBIC internals insist that an
+ordered subselect is necessary for an operation, and you believe there is a
+different/better way to get the same result - please file a bugreport.
+
=head1 AUTHOR
-See L<DBIx::Class/CONTRIBUTORS>.
+See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>.
=head1 LICENSE
projects / dbsrgits/DBIx-Class.git / blobdiff