NAME

DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server - Support specific to Microsoft SQL Server over ODBC

DESCRIPTION

This class implements support specific to Microsoft SQL Server over ODBC. It is loaded automatically by DBIx::Class::Storage::DBI::ODBC when it detects a MSSQL back-end.

Most of the functionality is provided from the superclass DBIx::Class::Storage::DBI::MSSQL.

USAGE NOTES

Basic Linux Setup (Debian)

  sudo aptitude install tdsodbc libdbd-odbc-perl unixodbc

In case it is not already there put the following (adjust for non-64bit arch) in "/etc/odbcinst.ini":

  [FreeTDS]
  Description = FreeTDS
  Driver      = /usr/lib/x86_64-linux-gnu/odbc/libtdsodbc.so
  Setup       = /usr/lib/x86_64-linux-gnu/odbc/libtdsS.so
  UsageCount  = 1

Set your $dsn in connect_info as follows:

  dbi:ODBC:server=<my.host.name>;port=1433;driver=FreeTDS;tds_version=8.0

If you use the EasySoft driver (<http://www.easysoft.com>):

  dbi:ODBC:server=<my.host.name>;port=1433;driver=Easysoft ODBC-SQL Server

Basic Windows Setup

Use the following $dsn for the Microsoft ODBC driver:

  dbi:ODBC:driver={SQL Server};server=SERVER\SQL_SERVER_INSTANCE_NAME

And for the Native Client:

  dbi:ODBC:driver={SQL Server Native Client 10.0};server=SERVER\SQL_SERVER_INSTANCE_NAME

Go into Control Panel -> System and Security -> Administrative Tools -> Data Sources (ODBC) to check driver names and to set up data sources.

Use System DSNs, not User DSNs if you want to use DSNs.

If you set up a DSN, use the following $dsn for connect_info:

  dbi:ODBC:dsn=MY_DSN

MULTIPLE ACTIVE STATEMENTS

The following options are alternative ways to enable concurrent executing statement support. Each has its own advantages and drawbacks and works on different platforms. Read each section carefully.

For more details about using MAS in MSSQL over DBD::ODBC see this excellent document provided by EasySoft: <http://www.easysoft.com/developer/languages/perl/multiple-active-statements.html>.

In order of preference, they are:

mars
dynamic_cursors
server_cursors

METHODS

connect_call_use_mars

Use as:

  on_connect_call => 'use_mars'

in your connection info, or alternatively specify it directly:

  Your::Schema->connect (
    $original_dsn . '; MARS_Connection=Yes',
    $user,
    $pass,
    \%attrs,
  )

Use to enable a feature of SQL Server 2005 and later, "Multiple Active Result Sets". See "Does DBD::ODBC support Multiple Active Statements?" in DBD::ODBC::FAQ for more information.

This does not work on FreeTDS drivers at the time of this writing, and only works with the Native Client, later versions of the Windows MS ODBC driver, and the Easysoft driver.

connect_call_use_dynamic_cursors

Use as:

  on_connect_call => 'use_dynamic_cursors'

Which will add "odbc_cursortype => 2" to your DBI connection attributes, or alternatively specify the necessary flag directly:

  Your::Schema->connect (@dsn, { ... odbc_cursortype => 2 })

See "odbc_cursortype" in DBD::ODBC for more information.

If you're using FreeTDS, "tds_version" must be set to at least 8.0.

This will not work with CODE ref connect_info's.

WARNING: on FreeTDS (and maybe some other drivers) this will break "SCOPE_IDENTITY()", and "SELECT @@IDENTITY" will be used instead, which on SQL Server 2005 and later will return erroneous results on tables which have an on insert trigger that inserts into another table with an "IDENTITY" column.

WARNING: on FreeTDS, changes made in one statement (e.g. an insert) may not be visible from a following statement (e.g. a select.)

WARNING: FreeTDS versions > 0.82 seem to have completely broken the ODBC protocol. DBIC will not allow dynamic cursor support with such versions to protect your data. Please hassle the authors of FreeTDS to act on the bugs that make their driver not overly usable with DBD::ODBC.

connect_call_use_server_cursors

Use as:

  on_connect_call => 'use_server_cursors'

May allow multiple active select statements. See "odbc_SQL_ROWSET_SIZE" in DBD::ODBC for more information.

Takes an optional parameter for the value to set the attribute to, default is 2.

WARNING: this does not work on all versions of SQL Server, and may lock up your database!

At the time of writing, this option only works on Microsoft's Windows drivers, later versions of the ODBC driver and the Native Client driver.

FURTHER QUESTIONS?

Check the list of additional DBIC resources.

COPYRIGHT AND LICENSE

This module is free software copyright by the DBIx::Class (DBIC) authors. You can redistribute it and/or modify it under the same terms as the DBIx::Class library.