X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FMSSQL.pm;h=30b66feda9a91bdcf8ba70dbac8840d361b3c718;hb=4b8a53eabdb1629bacdb95f04ca8fc3718ca7c58;hp=c4611b3455ea3769c3c0ef8b86b34070fb49a832;hpb=afcfff010f5a1d6dbc3a5fb6dfbaeb6246c33372;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBI/MSSQL.pm b/lib/DBIx/Class/Storage/DBI/MSSQL.pm index c4611b3..30b66fe 100644 --- a/lib/DBIx/Class/Storage/DBI/MSSQL.pm +++ b/lib/DBIx/Class/Storage/DBI/MSSQL.pm @@ -3,98 +3,47 @@ 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 + DBIx::Class::Storage::DBI::IdentityInsert +/; 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 + _identity _identity_method _no_scope_identity_query /); -__PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks::MSSQL'); +__PACKAGE__->sql_maker_class('DBIx::Class::SQLMaker::MSSQL'); -sub _set_identity_insert { - my ($self, $table) = @_; - $self->_get_dbh->do (sprintf - 'SET IDENTITY_INSERT %s ON', - $self->sql_maker->_quote ($table) - ); -} - -sub insert_bulk { - my $self = shift; - my ($source, $cols, $data) = @_; - - if (List::Util::first - { $source->column_info ($_)->{is_auto_increment} } - (@{$cols}) - ) { - $self->_set_identity_insert ($source->name); - } - - $self->next::method(@_); -} - -# 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; +__PACKAGE__->sql_quote_char([qw/[ ]/]); - my @get_guids_for = - grep { not exists $to_insert->{$_} } (@pk_guids, @auto_guids); +__PACKAGE__->datetime_parser_type ( + 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' +); - 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; - } - - if (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) ) { - $self->_set_identity_insert ($source->name); - } - - $updated_cols = { %$updated_cols, %{ $self->next::method(@_) } }; - - return $updated_cols; -} +__PACKAGE__->new_guid('NEWID()'); sub _prep_for_execute { my $self = shift; - my ($op, $extra_bind, $ident, $args) = @_; + my ($op, $ident, $args) = @_; # cast MONEY values properly if ($op eq 'insert' || $op eq 'update') { my $fields = $args->[0]; + my $colinfo = $ident->columns_info([keys %$fields]); + for my $col (keys %$fields) { # $ident is a result source object with INSERT/UPDATE ops - if ($ident->column_info ($col)->{data_type} - && - $ident->column_info ($col)->{data_type} =~ /^money\z/i) { + if ( + $colinfo->{$col}{data_type} + && + $colinfo->{$col}{data_type} =~ /^money\z/i + ) { my $val = $fields->{$col}; $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]]; } @@ -103,9 +52,16 @@ sub _prep_for_execute { my ($sql, $bind) = $self->next::method (@_); - if ($op eq 'insert') { - $sql .= ';SELECT SCOPE_IDENTITY()'; - + # SELECT SCOPE_IDENTITY only works within a statement scope. We + # must try to always use this particular idiom frist, as it is the + # only one that guarantees retrieving the correct id under high + # concurrency. When this fails we will fall back to whatever secondary + # retrieval method is specified in _identity_method, but at this + # point we don't have many guarantees we will get what we expected. + # http://msdn.microsoft.com/en-us/library/ms190315.aspx + # http://davidhayden.com/blog/dave/archive/2006/01/17/2736.aspx + if ($self->_perform_autoinc_retrieval and not $self->_no_scope_identity_query) { + $sql .= "\nSELECT SCOPE_IDENTITY()"; } return ($sql, $bind); @@ -113,15 +69,21 @@ sub _prep_for_execute { sub _execute { my $self = shift; - my ($op) = @_; - my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_); + # always list ctx - we need the $sth + my ($rv, $sth, @bind) = $self->next::method(@_); - if ($op eq 'insert') { + if ($self->_perform_autoinc_retrieval) { - # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked + # attempt to bring back the result of SELECT SCOPE_IDENTITY() we tacked # on in _prep_for_execute above - my ($identity) = $sth->fetchrow_array; + my $identity; + + # we didn't even try on ftds + unless ($self->_no_scope_identity_query) { + ($identity) = try { $sth->fetchrow_array }; + $sth->finish; + } # SCOPE_IDENTITY failed, but we can do something else if ( (! $identity) && $self->_identity_method) { @@ -131,7 +93,6 @@ sub _execute { } $self->_identity($identity); - $sth->finish; } return wantarray ? ($rv, $sth, @bind) : $rv; @@ -139,41 +100,140 @@ sub _execute { sub last_insert_id { shift->_identity } +# +# 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 $self = shift; + + my ($sql, $prep_bind, @rest) = $self->next::method (@_); + + # see if this is an ordered subquery + my $attrs = $_[3]; + if ( + $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi + && + scalar $self->_extract_order_criteria ($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 = $self->sql_maker->__max_int; + $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi; + } + + return wantarray + ? ($sql, $prep_bind, @rest) + : \[ "($sql)", @$prep_bind ] + ; +} + + # savepoint syntax is the same as in Sybase ASE -sub _svp_begin { +sub _exec_svp_begin { my ($self, $name) = @_; - $self->_get_dbh->do("SAVE TRANSACTION $name"); + $self->_dbh->do("SAVE TRANSACTION $name"); } # A new SAVE TRANSACTION with the same name releases the previous one. -sub _svp_release { 1 } +sub _exec_svp_release { 1 } -sub _svp_rollback { +sub _exec_svp_rollback { my ($self, $name) = @_; - $self->_get_dbh->do("ROLLBACK TRANSACTION $name"); + $self->_dbh->do("ROLLBACK TRANSACTION $name"); } -sub build_datetime_parser { +sub sqlt_type { 'SQLServer' } + +sub sql_limit_dialect { 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 + + 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 $supports_rno ? 'RowNumberOver' : 'Top'; } -sub sqlt_type { 'SQLServer' } +sub _ping { + my $self = shift; -sub _sql_maker_opts { - my ( $self, $opts ) = @_; + my $dbh = $self->_dbh or return 0; - if ( $opts ) { - $self->{_sql_maker_opts} = { %$opts }; - } + local $dbh->{RaiseError} = 1; + local $dbh->{PrintError} = 0; - return { limit_dialect => 'Top', %{$self->{_sql_maker_opts}||{}} }; + 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; @@ -211,17 +271,67 @@ This is more dangerous, as inserting into a table with an on insert trigger that inserts into another table with an identity will give erroneous results on recent versions of SQL Server. -=head2 bulk_insert +=head2 identity insert Be aware that we have tried to make things as simple as possible for our users. -For MSSQL that means that when a user tries to do a populate/bulk_insert which -includes an autoincrementing column, we will try to tell the database to allow -the insertion of the autoinc column. But the user must have the db_ddladmin -role membership, otherwise you will get a fairly opaque error message. +For MSSQL that means that when a user tries to create a row, while supplying an +explicit value for an autoincrementing column, we will try to issue the +appropriate database call to make this possible, namely C. 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