X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FMSSQL.pm;h=5d14612274b8d612abe9a4999400522ee1d42aae;hb=7d3139ac1ff52213e2dad35fc9c9d1057711256a;hp=28b87f2ed6755699c81a74f8186d8a1236a14af7;hpb=6553ac3837081c481ecdf269c7aff407c348a807;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBI/MSSQL.pm b/lib/DBIx/Class/Storage/DBI/MSSQL.pm index 28b87f2..5d14612 100644 --- a/lib/DBIx/Class/Storage/DBI/MSSQL.pm +++ b/lib/DBIx/Class/Storage/DBI/MSSQL.pm @@ -3,16 +3,17 @@ package DBIx::Class::Storage::DBI::MSSQL; 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(); +use Try::Tiny; +use List::Util 'first'; +use namespace::clean; __PACKAGE__->mk_group_accessors(simple => qw/ _identity _identity_method /); -__PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks::MSSQL'); +__PACKAGE__->sql_maker_class('DBIx::Class::SQLMaker::MSSQL'); sub _set_identity_insert { my ($self, $table) = @_; @@ -23,13 +24,13 @@ sub _set_identity_insert { ); my $dbh = $self->_get_dbh; - eval { $dbh->do ($sql) }; - if ($@) { + try { $dbh->do ($sql) } + catch { $self->throw_exception (sprintf "Error executing '%s': %s", $sql, $dbh->errstr, ); - } + }; } sub _unset_identity_insert { @@ -48,12 +49,8 @@ sub insert_bulk { my $self = shift; my ($source, $cols, $data) = @_; - my $is_identity_insert = (List::Util::first - { $source->column_info ($_)->{is_auto_increment} } - (@{$cols}) - ) - ? 1 - : 0; + my $is_identity_insert = + (first { $source->column_info ($_)->{is_auto_increment} } @{$cols}) ? 1 : 0; if ($is_identity_insert) { $self->_set_identity_insert ($source->name); @@ -66,58 +63,25 @@ sub insert_bulk { } } -# 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; + my $is_identity_insert = + (first { $_->{is_auto_increment} } values %$supplied_col_info) ? 1 : 0; if ($is_identity_insert) { $self->_set_identity_insert ($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 $updated_cols; } @@ -160,7 +124,7 @@ sub _execute { # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked # on in _prep_for_execute above - my ($identity) = eval { $sth->fetchrow_array }; + my ($identity) = try { $sth->fetchrow_array }; # SCOPE_IDENTITY failed, but we can do something else if ( (! $identity) && $self->_identity_method) { @@ -179,33 +143,29 @@ sub _execute { sub last_insert_id { shift->_identity } # -# MSSQL is retarded wrt ordered subselects. One needs to add a TOP 100% -# to *all* subqueries, do it here. +# MSSQL is retarded wrt ordered subselects. One needs to add a TOP +# to *all* subqueries, but one also *can't* use TOP 100 PERCENT +# http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 # sub _select_args_to_query { my $self = shift; - # _select_args does some shady action at a distance - # see DBI.pm for more info - my $sql_maker = $self->sql_maker; - my ($op, $bind, $ident, $bind_attrs, $select, $cond, $order, $rows, $offset); - { - local $sql_maker->{_dbic_rs_attrs}; - ($op, $bind, $ident, $bind_attrs, $select, $cond, $order, $rows, $offset) = $self->_select_args(@_); - } + my ($sql, $prep_bind, @rest) = $self->next::method (@_); + # see if this is an ordered subquery + my $attrs = $_[3]; if ( - ($rows || $offset) - || - not scalar $sql_maker->_order_by_chunks ($order->{order_by}) + $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi + && + scalar $self->_extract_order_columns ($attrs->{order_by}) ) { - # either limited RS or no ordering, just short circuit - return $self->next::method (@_); + $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 = $self->sql_maker->__max_int; + $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi; } - my ($sql, $prep_bind, @rest) = $self->next::method (@_); - $sql =~ s/^ \s* SELECT \s/SELECT TOP 100 PERCENT /xi; - return wantarray ? ($sql, $prep_bind, @rest) : \[ "($sql)", @$prep_bind ] @@ -230,24 +190,96 @@ sub _svp_rollback { $self->_get_dbh->do("ROLLBACK TRANSACTION $name"); } -sub build_datetime_parser { - my $self = shift; - my $type = "DateTime::Format::Strptime"; - eval "use ${type}"; - $self->throw_exception("Couldn't load ${type}: $@") if $@; - return $type->new( pattern => '%Y-%m-%d %H:%M:%S' ); # %F %T +sub datetime_parser_type { + 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' } sub sqlt_type { 'SQLServer' } -sub _sql_maker_opts { - my ( $self, $opts ) = @_; +sub sql_limit_dialect { + my $self = shift; - if ( $opts ) { - $self->{_sql_maker_opts} = { %$opts }; + my $supports_rno = 0; + + if (exists $self->_server_info->{normalized_dbms_version}) { + $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; + } + else { + # User is connecting via DBD::Sybase and has no permission to run + # stored procedures like xp_msver, or version detection failed for some + # other reason. + # So, we use a query to check if RNO is implemented. + try { + $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); + $supports_rno = 1; + }; } - return { limit_dialect => 'RowNumberOver', %{$self->{_sql_maker_opts}||{}} }; + return $supports_rno ? 'RowNumberOver' : 'Top'; +} + +sub _ping { + my $self = shift; + + my $dbh = $self->_dbh or return 0; + + local $dbh->{RaiseError} = 1; + local $dbh->{PrintError} = 0; + + return try { + $dbh->do('select 1'); + 1; + } catch { + 0; + }; +} + +package # hide from PAUSE + DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; + +my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T +my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; + +my ($datetime_parser, $smalldatetime_parser); + +sub parse_datetime { + shift; + require DateTime::Format::Strptime; + $datetime_parser ||= DateTime::Format::Strptime->new( + pattern => $datetime_format, + on_error => 'croak', + ); + return $datetime_parser->parse_datetime(shift); +} + +sub format_datetime { + shift; + require DateTime::Format::Strptime; + $datetime_parser ||= DateTime::Format::Strptime->new( + pattern => $datetime_format, + on_error => 'croak', + ); + return $datetime_parser->format_datetime(shift); +} + +sub parse_smalldatetime { + shift; + require DateTime::Format::Strptime; + $smalldatetime_parser ||= DateTime::Format::Strptime->new( + pattern => $smalldatetime_format, + on_error => 'croak', + ); + return $smalldatetime_parser->parse_datetime(shift); +} + +sub format_smalldatetime { + shift; + require DateTime::Format::Strptime; + $smalldatetime_parser ||= DateTime::Format::Strptime->new( + pattern => $smalldatetime_format, + on_error => 'croak', + ); + return $smalldatetime_parser->format_datetime(shift); } 1; @@ -295,9 +327,57 @@ $table_name ON>. Unfortunately this operation in MSSQL requires the C 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 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. +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 C. +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. +See L and L. =head1 LICENSE