X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FMSSQL.pm;h=ea4b079694113dfeb37bc051e0535ce6e17ba24d;hb=fd323bf1046faa7de5a8c985268d80ec5b703361;hp=c6b93605a6d1aab7bfcbb3b9f2d616a3a49f6282;hpb=48fe908793f2a2141bb687946c18f9a54ae2c47f;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBI/MSSQL.pm b/lib/DBIx/Class/Storage/DBI/MSSQL.pm
index c6b9360..ea4b079 100644
--- a/lib/DBIx/Class/Storage/DBI/MSSQL.pm
+++ b/lib/DBIx/Class/Storage/DBI/MSSQL.pm
@@ -3,68 +3,398 @@ 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 Try::Tiny;
+use namespace::clean;
 
-sub _dbh_last_insert_id {
-  my ($self, $dbh, $source, $col) = @_;
-  my ($id) = $dbh->selectrow_array('SELECT SCOPE_IDENTITY()');
-  return $id;
+use List::Util();
+
+__PACKAGE__->mk_group_accessors(simple => qw/
+  _identity _identity_method
+/);
+
+__PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks::MSSQL');
+
+sub _set_identity_insert {
+  my ($self, $table) = @_;
+
+  my $sql = sprintf (
+    'SET IDENTITY_INSERT %s ON',
+    $self->sql_maker->_quote ($table),
+  );
+
+  my $dbh = $self->_get_dbh;
+  try { $dbh->do ($sql) }
+  catch {
+    $self->throw_exception (sprintf "Error executing '%s': %s",
+      $sql,
+      $dbh->errstr,
+    );
+  };
+}
+
+sub _unset_identity_insert {
+  my ($self, $table) = @_;
+
+  my $sql = sprintf (
+    'SET IDENTITY_INSERT %s OFF',
+    $self->sql_maker->_quote ($table),
+  );
+
+  my $dbh = $self->_get_dbh;
+  $dbh->do ($sql);
+}
+
+sub insert_bulk {
+  my $self = shift;
+  my ($source, $cols, $data) = @_;
+
+  my $is_identity_insert = (List::Util::first
+      { $source->column_info ($_)->{is_auto_increment} }
+      (@{$cols})
+  )
+     ? 1
+     : 0;
+
+  if ($is_identity_insert) {
+     $self->_set_identity_insert ($source->name);
+  }
+
+  $self->next::method(@_);
+
+  if ($is_identity_insert) {
+     $self->_unset_identity_insert ($source->name);
+  }
+}
+
+sub insert {
+  my $self = shift;
+  my ($source, $to_insert) = @_;
+
+  my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] );
+
+  my $is_identity_insert = (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) )
+     ? 1
+     : 0;
+
+  if ($is_identity_insert) {
+     $self->_set_identity_insert ($source->name);
+  }
+
+  my $updated_cols = $self->next::method(@_);
+
+  if ($is_identity_insert) {
+     $self->_unset_identity_insert ($source->name);
+  }
+
+  return $updated_cols;
+}
+
+sub _prep_for_execute {
+  my $self = shift;
+  my ($op, $extra_bind, $ident, $args) = @_;
+
+# cast MONEY values properly
+  if ($op eq 'insert' || $op eq 'update') {
+    my $fields = $args->[0];
+
+    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) {
+        my $val = $fields->{$col};
+        $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]];
+      }
+    }
+  }
+
+  my ($sql, $bind) = $self->next::method (@_);
+
+  if ($op eq 'insert') {
+    $sql .= ';SELECT SCOPE_IDENTITY()';
+
+  }
+
+  return ($sql, $bind);
 }
 
-sub build_datetime_parser {
+sub _execute {
+  my $self = shift;
+  my ($op) = @_;
+
+  my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_);
+
+  if ($op eq 'insert') {
+
+    # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked
+    # on in _prep_for_execute above
+    my ($identity) = try { $sth->fetchrow_array };
+
+    # SCOPE_IDENTITY failed, but we can do something else
+    if ( (! $identity) && $self->_identity_method) {
+      ($identity) = $self->_dbh->selectrow_array(
+        'select ' . $self->_identity_method
+      );
+    }
+
+    $self->_identity($identity);
+    $sth->finish;
+  }
+
+  return wantarray ? ($rv, $sth, @bind) : $rv;
+}
+
+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 $type = "DateTime::Format::Strptime";
-  eval "use ${type}";
-  $self->throw_exception("Couldn't load ${type}: $@") if $@;
-  return $type->new( pattern => '%Y-%m-%d %H:%M:%S' );  # %F %T
+
+  my ($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 $self->_parse_order_by ($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 $max /xi;
+  }
+
+  return wantarray
+    ? ($sql, $prep_bind, @rest)
+    : \[ "($sql)", @$prep_bind ]
+  ;
+}
+
+
+# savepoint syntax is the same as in Sybase ASE
+
+sub _svp_begin {
+  my ($self, $name) = @_;
+
+  $self->_get_dbh->do("SAVE TRANSACTION $name");
+}
+
+# A new SAVE TRANSACTION with the same name releases the previous one.
+sub _svp_release { 1 }
+
+sub _svp_rollback {
+  my ($self, $name) = @_;
+
+  $self->_get_dbh->do("ROLLBACK TRANSACTION $name");
+}
+
+sub datetime_parser_type {
+  'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format'
 }
 
 sub sqlt_type { 'SQLServer' }
 
-sub _sql_maker_opts {
-    my ( $self, $opts ) = @_;
+sub sql_maker {
+  my $self = shift;
+
+  unless ($self->_sql_maker) {
+    unless ($self->{_sql_maker_opts}{limit_dialect}) {
+      my $have_rno = 0;
+
+      if (exists $self->_server_info->{normalized_dbms_version}) {
+        $have_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())');
+          $have_rno = 1;
+        };
+      }
 
-    if ( $opts ) {
-        $self->{_sql_maker_opts} = { %$opts };
+      $self->{_sql_maker_opts} = {
+        limit_dialect => ($have_rno ? 'RowNumberOver' : 'Top'),
+        %{$self->{_sql_maker_opts}||{}}
+      };
     }
 
-    return { limit_dialect => 'Top', %{$self->{_sql_maker_opts}||{}} };
+    my $maker = $self->next::method (@_);
+  }
+
+  return $self->_sql_maker;
+}
+
+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;
 
 =head1 NAME
 
-DBIx::Class::Storage::DBI::MSSQL - Storage::DBI subclass for MSSQL
+DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support
+in DBIx::Class
 
 =head1 SYNOPSIS
 
-This subclass supports MSSQL, and can in theory be used directly
-via the C<storage_type> mechanism:
+This is the base class for Microsoft SQL Server support, used by
+L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and
+L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>.
+
+=head1 IMPLEMENTATION NOTES
+
+=head2 IDENTITY information
+
+Microsoft SQL Server supports three methods of retrieving the IDENTITY
+value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY().
+SCOPE_IDENTITY is used here because it is the safest.  However, it must
+be called is the same execute statement, not just the same connection.
+
+So, this implementation appends a SELECT SCOPE_IDENTITY() statement
+onto each INSERT to accommodate that requirement.
+
+C<SELECT @@IDENTITY> can also be used by issuing:
+
+  $self->_identity_method('@@identity');
+
+it will only be used if SCOPE_IDENTITY() fails.
+
+This is more dangerous, as inserting into a table with an on insert trigger that
+inserts into another table with an identity will give erroneous results on
+recent versions of SQL Server.
+
+=head2 identity insert
+
+Be aware that we have tried to make things as simple as possible for our users.
+For MSSQL that means that when a user tries to create a row, while supplying an
+explicit value for an autoincrementing column, we will try to issue the
+appropriate database call to make this possible, namely C<SET IDENTITY_INSERT
+$table_name ON>. Unfortunately this operation in MSSQL requires the
+C<db_ddladmin> privilege, which is normally not included in the standard
+write-permissions.
+
+=head2 Ordered Subselects
 
-  $schema->storage_type('::DBI::MSSQL');
-  $schema->connect_info('dbi:....', ...);
+If you attempted the following query (among many others) in Microsoft SQL
+Server
 
-However, as there is no L<DBD::MSSQL>, you will probably want to use
-one of the other DBD-specific MSSQL classes, such as
-L<DBIx::Class::Storage::DBI::Sybase::MSSQL>.  These classes will
-merge this class with a DBD-specific class to obtain fully
-correct behavior for your scenario.
+ $rs->search ({}, {
+  prefetch => 'relation',
+  rows => 2,
+  offset => 3,
+ });
 
-=head1 METHODS
+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.
 
-=head2 last_insert_id
+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.
 
-=head2 sqlt_type
+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:
 
-=head2 build_datetime_parser
+ $rs->search ({}, {
+  unsafe_subselect_ok => 1,
+  prefetch => 'relation',
+  rows => 2,
+  offset => 3,
+ });
 
-The resulting parser handles the MSSQL C<DATETIME> type, but is almost
-certainly not sufficient for the other MSSQL 2008 date/time types.
+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 AUTHORS
+=head1 AUTHOR
 
-Brian Cassidy <bricas@cpan.org>
+See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>.
 
 =head1 LICENSE