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1 | package DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server; |
2 | use strict; |
3 | use warnings; |
4 | |
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5 | use base qw/DBIx::Class::Storage::DBI::MSSQL/; |
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6 | use mro 'c3'; |
7 | |
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8 | use Carp::Clan qw/^DBIx::Class/; |
9 | use List::Util(); |
10 | use Scalar::Util (); |
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11 | |
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12 | __PACKAGE__->mk_group_accessors(simple => qw/ |
13 | _using_dynamic_cursors |
14 | /); |
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15 | |
16 | =head1 NAME |
17 | |
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18 | DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server - Support specific |
19 | to Microsoft SQL Server over ODBC |
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20 | |
21 | =head1 DESCRIPTION |
22 | |
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23 | This class implements support specific to Microsoft SQL Server over ODBC. It is |
24 | loaded automatically by by DBIx::Class::Storage::DBI::ODBC when it detects a |
25 | MSSQL back-end. |
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26 | |
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27 | Most of the functionality is provided from the superclass |
28 | L<DBIx::Class::Storage::DBI::MSSQL>. |
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29 | |
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30 | =head1 MULTIPLE ACTIVE STATEMENTS |
31 | |
32 | The following options are alternative ways to enable concurrent executing |
33 | statement support. Each has its own advantages and drawbacks. |
34 | |
35 | =head2 connect_call_use_dynamic_cursors |
36 | |
37 | Use as: |
38 | |
39 | on_connect_call => 'use_dynamic_cursors' |
40 | |
41 | in your L<DBIx::Class::Storage::DBI/connect_info> as one way to enable multiple |
42 | concurrent statements. |
43 | |
44 | Will add C<< odbc_cursortype => 2 >> to your DBI connection attributes. See |
45 | L<DBD::ODBC/odbc_cursortype> for more information. |
46 | |
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47 | Alternatively, you can add it yourself and dynamic cursor support will be |
48 | automatically enabled. |
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49 | |
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50 | If you're using FreeTDS, C<tds_version> must be set to at least C<8.0>. |
51 | |
52 | This will not work with CODE ref connect_info's. |
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53 | |
54 | B<WARNING:> this will break C<SCOPE_IDENTITY()>, and C<SELECT @@IDENTITY> will |
55 | be used instead, which on SQL Server 2005 and later will return erroneous |
56 | results on tables which have an on insert trigger that inserts into another |
57 | table with an C<IDENTITY> column. |
58 | |
59 | =cut |
60 | |
61 | sub connect_call_use_dynamic_cursors { |
62 | my $self = shift; |
63 | |
64 | if (ref($self->_dbi_connect_info->[0]) eq 'CODE') { |
65 | croak 'cannot set DBI attributes on a CODE ref connect_info'; |
66 | } |
67 | |
68 | my $dbi_attrs = $self->_dbi_connect_info->[-1]; |
69 | |
70 | unless (ref($dbi_attrs) && Scalar::Util::reftype($dbi_attrs) eq 'HASH') { |
71 | $dbi_attrs = {}; |
72 | push @{ $self->_dbi_connect_info }, $dbi_attrs; |
73 | } |
74 | |
75 | if (not exists $dbi_attrs->{odbc_cursortype}) { |
76 | # turn on support for multiple concurrent statements, unless overridden |
77 | $dbi_attrs->{odbc_cursortype} = 2; |
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78 | $self->disconnect; # resetting dbi attrs, so have to reconnect |
79 | $self->ensure_connected; |
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80 | $self->_set_dynamic_cursors; |
81 | } |
82 | } |
83 | |
84 | sub _set_dynamic_cursors { |
85 | my $self = shift; |
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86 | my $dbh = $self->_dbh; |
87 | |
88 | eval { |
89 | local $dbh->{RaiseError} = 1; |
90 | local $dbh->{PrintError} = 0; |
91 | $dbh->do('SELECT @@IDENTITY'); |
92 | }; |
93 | if ($@) { |
94 | croak <<'EOF'; |
95 | |
96 | Your drivers do not seem to support dynamic cursors (odbc_cursortype => 2), |
97 | if you're using FreeTDS, make sure to set tds_version to 8.0 or greater. |
98 | EOF |
99 | } |
100 | |
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101 | $self->_using_dynamic_cursors(1); |
102 | $self->_identity_method('@@identity'); |
103 | } |
104 | |
105 | sub _rebless { |
106 | no warnings 'uninitialized'; |
107 | my $self = shift; |
108 | |
109 | if (ref($self->_dbi_connect_info->[0]) ne 'CODE' && |
110 | eval { $self->_dbi_connect_info->[-1]{odbc_cursortype} } == 2) { |
111 | $self->_set_dynamic_cursors; |
112 | return; |
113 | } |
114 | |
115 | $self->_using_dynamic_cursors(0); |
116 | } |
117 | |
118 | =head2 connect_call_use_server_cursors |
119 | |
120 | Use as: |
121 | |
122 | on_connect_call => 'use_server_cursors' |
123 | |
124 | May allow multiple active select statements. See |
125 | L<DBD::ODBC/odbc_SQL_ROWSET_SIZE> for more information. |
126 | |
127 | Takes an optional parameter for the value to set the attribute to, default is |
128 | C<2>. |
129 | |
130 | B<WARNING>: this does not work on all versions of SQL Server, and may lock up |
131 | your database! |
132 | |
133 | =cut |
134 | |
135 | sub connect_call_use_server_cursors { |
136 | my $self = shift; |
137 | my $sql_rowset_size = shift || 2; |
138 | |
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139 | $self->_get_dbh->{odbc_SQL_ROWSET_SIZE} = $sql_rowset_size; |
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140 | } |
141 | |
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142 | =head2 connect_call_use_MARS |
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143 | |
144 | Use as: |
145 | |
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146 | on_connect_call => 'use_MARS' |
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147 | |
148 | Use to enable a feature of SQL Server 2005 and later, "Multiple Active Result |
149 | Sets". See L<DBD::ODBC::FAQ/Does DBD::ODBC support Multiple Active Statements?> |
150 | for more information. |
151 | |
152 | B<WARNING>: This has implications for the way transactions are handled. |
153 | |
154 | =cut |
155 | |
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156 | sub connect_call_use_MARS { |
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157 | my $self = shift; |
158 | |
159 | my $dsn = $self->_dbi_connect_info->[0]; |
160 | |
161 | if (ref($dsn) eq 'CODE') { |
162 | croak 'cannot change the DBI DSN on a CODE ref connect_info'; |
163 | } |
164 | |
165 | if ($dsn !~ /MARS_Connection=/) { |
166 | $self->_dbi_connect_info->[0] = "$dsn;MARS_Connection=Yes"; |
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167 | my $was_connected = defined $self->_dbh; |
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168 | $self->disconnect; |
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169 | $self->ensure_connected if $was_connected; |
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170 | } |
171 | } |
172 | |
173 | 1; |
174 | |
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175 | =head1 AUTHOR |
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176 | |
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177 | See L<DBIx::Class/CONTRIBUTORS>. |
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178 | |
179 | =head1 LICENSE |
180 | |
181 | You may distribute this code under the same terms as Perl itself. |
182 | |
183 | =cut |
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184 | # vim: sw=2 sts=2 |