++ed by:
KEEDI ECARROLL MICHIELB MELO MJEVANS

5 PAUSE users
7 non-PAUSE users.

Martin J Evans
and 1 contributors

NAME

DBD::ODBC - ODBC Driver for DBI

SYNOPSIS

  use DBI;

  $dbh = DBI->connect('dbi:ODBC:DSN', 'user', 'password');

See DBI for more information.

DESCRIPTION

Change log and FAQs

Please note that the change log has been moved to DBD::ODBC::Changes.pm. To access this documentation, use perldoc DBD::ODBC::Changes.

For FAQs see "Frequently Asked Questions" or http://dbi.perl.org.

Important note about the tests

Please note that some tests may fail or report they are unsupported on this platform. Notably Oracle's ODBC driver will fail the "advanced" binding tests in t/08bind2.t. These tests run perfectly under SQL Server 2000. This is normal and expected. Until Oracle fixes their drivers to do the right thing from an ODBC perspective, it's going to be tough to fix the issue. The workaround for Oracle is to bind date types with SQL_TIMESTAMP. Also note that some tests may be skipped, such as t/09multi.t, if your driver doesn't seem to support returning multiple result sets. This is normal.

Version Control

DBD::ODBC source code is under version control at svn.perl.org. If you would like to use the "bleeding" edge version, you can get the latest from svn.perl.org via Subversion version control. Note there is no guarantee that this version is any different than what you get from the tarball from CPAN, but it might be :)

You may read about Subversion at http://subversion.tigris.org

You can get a subversion client from there and check dbd-odbc out via:

   svn checkout http://svn.perl.org/modules/dbd-odbc/trunk <your directory name here>

Which will pull all the files from the subversion trunk to your specified directory. If you want to see what has changed since the last release of DBD::ODBC read the Changes file or use "svn log" to get a list of checked in changes.

Contributing

Please use Subversion (see above) to get the latest version of DBD::ODBC from the trunk and submit any patches against that.

Please, before submitting a patch:

   svn update
   <try and included a test which demonstrates the fix/change working>
   <test your patch>
   svn diff > describe_my_diffs.patch

and send the resulting file to me and cc the dbi-users@perl.org mailing list (if you are not a member - why not!).

Private attributes common to connection and statement handles

odbc_ignore_named_placeholders

Use this if you have special needs (such as Oracle triggers, etc) where :new or :name mean something special and are not just place holder names You must then use ? for binding parameters. Example:

 $dbh->{odbc_ignore_named_placeholders} = 1;
 $dbh->do("create trigger foo as if :new.x <> :old.x then ... etc");

Without this, DBD::ODBC will think :new and :old are placeholders for binding and get confused.

odbc_default_bind_type

This value defaults to 0.

Older versions of DBD::ODBC assumed that the binding type was 12 (SQL_VARCHAR). Newer versions default to 0, which means that DBD::ODBC will attempt to query the driver via SQLDescribeParam to determine the correct type. If the driver doesn't support SQLDescribeParam, then DBD::ODBC falls back to using SQL_VARCHAR as the default, unless overridden by bind_param().

odbc_force_rebind

This is to handle special cases, especially when using multiple result sets. Set this before execute to "force" DBD::ODBC to re-obtain the result set's number of columns and column types for each execute. Especially useful for calling stored procedures which may return different result sets each execute. The only performance penalty is during execute(), but I didn't want to incur that penalty for all circumstances. It is probably fairly rare that this occurs. This attribute will be automatically set when multiple result sets are triggered. Most people shouldn't have to worry about this.

odbc_async_exec

Allow asynchronous execution of queries. This causes a spin-loop (with a small "sleep") until the SQL is complete. This is useful, however, if you want the error handling and asynchronous messages (see the "odbc_err_handler" and t/20SQLServer.t for an example of this.

odbc_query_timeout

This allows the end user to set a timeout for queries on the ODBC side. Add

  { odbc_query_timeout => 30 }

to you connect or set on the dbh before executing the statement. The default is 0, no timeout.

Note that some drivers may not support this attribute.

See t/20SqlServer.t for an example.

Private connection attributes

odbc_err_handler

Allow errors to be handled by the application. A call-back function supplied by the application to handle or ignore messages.

The callback function receives three parameters: state (string), error (string) and the native error code (number).

If the error handler returns 0, the error is ignored, otherwise the error is passed through the normal DBI error handling.

This can also be used for procedures under MS SQL Server (Sybase too, probably) to obtain messages from system procedures such as DBCC. Check t/20SQLServer.t and t/10handler.t.

  $dbh->{RaiseError} = 1;
  sub err_handler {
     ($state, $msg, $native) = @_;
     if ($state = '12345')
         return 0; # ignore this error
     else
         return 1; # propagate error
  }
  $dbh->{odbc_err_handler} = \$err_handler;
  # do something to cause an error
  $dbh->{odbc_err_handler} = undef; # cancel the handler

odbc_SQL_ROWSET_SIZE

Here is the information from the original patch, however, I've learned since from other sources that this could/has caused SQL Server to "lock up". Please use at your own risk!

SQL_ROWSET_SIZE attribute patch from Andrew Brown > There are only 2 additional lines allowing for the setting of > SQL_ROWSET_SIZE as db handle option. > > The purpose to my madness is simple. SqlServer (7 anyway) by default > supports only one select statement at once (using std ODBC cursors). > According to the SqlServer documentation you can alter the default setting > of > three values to force the use of server cursors - in which case multiple > selects are possible. > > The code change allows for: > $dbh->{SQL_ROWSET_SIZE} = 2; # Any value > 1 > > For this very purpose. > > The setting of SQL_ROWSET_SIZE only affects the extended fetch command as > far as I can work out and thus setting this option shouldn't affect > DBD::ODBC operations directly in any way. > > Andrew >

odbc_exec_direct

Force DBD::ODBC to use SQLExecDirect instead of SQLPrepare/SQLExecute.

There are drivers that only support SQLExecDirect and the DBD::ODBC do() override does not allow returning result sets. Therefore, the way to do this now is to set the attribute odbc_exec_direct.

NOTE: You may also want to use this option if you are creating temporary objects (e.g., tables) in MS SQL Server and for some reason cannot use the do method. see http://technet.microsoft.com/en-US/library/ms131667.aspx which says Prepared statements cannot be used to create temporary objects on SQL Server 2000 or later.... Without odbc_exec_direct, the temporary object will disappear before you can use it.

There are currently two ways to get this:

    $dbh->prepare($sql, { odbc_exec_direct => 1});

and

    $dbh->{odbc_exec_direct} = 1;

SQL_DRIVER_ODBC_VER

This, while available via get_info() is captured here. I may get rid of this as I only used it for debugging purposes.

odbc_cursortype

This allows multiple concurrent statements on SQL*Server. In your connect, add

  { odbc_cursortype => 2 }.

If you are using DBI > 1.41, you should also be able to use

 { odbc_cursortype => DBI::SQL_CURSOR_DYNAMIC }

instead. For example:

    my $dbh = DBI->connect("dbi:ODBC:$DSN", $user, $pass,
                  { RaiseError => 1, odbc_cursortype => 2});
    my $sth = $dbh->prepare("one statement");
    my $sth2 = $dbh->prepare("two statement");
    $sth->execute;
    my @row;
    while (@row = $sth->fetchrow_array) {
       $sth2->execute($row[0]);
    }

See t/20SqlServer.t for an example.

odbc_has_unicode

A read-only attribute signifying whether DBD::ODBC was built with the C macro WITH_UNICODE or not. A value of 1 indicates DBD::ODBC was built with WITH_UNICODE else the value returned is 0.

Building WITH_UNICODE affects columns and parameters which are SQL_C_WCHAR, SQL_WCHAR, SQL_WVARCHAR, and SQL_WLONGVARCHAR.

When odbc_has_unicode is 1, DBD::ODBC will:

bind columns the database declares as wide characters as SQL_Wxxx

This means that UNICODE data stored in these columns will be returned to Perl in UTF-8 and with the UTF8 flag set.

bind parameters the database declares as wide characters as SQL_Wxxx

Parameters bound where the database declares the parameter as being a wide character (or where the parameter type is explicitly set to a wide type - SQL_Wxxx) can be UTF8 in Perl and will be mapped to UTF16 before passing to the driver.

NOTE: You will need at least Perl 5.8.1 to use UNICODE with DBD::ODBC.

NOTE: At this time SQL statements are still treated as native encoding i.e. DBD::ODBC does not call SQLPrepareW with UNICODE strings. If you need a unicode constant in an SQL statement, you have to pass it as parameter or use SQL functions to convert your constant from native encoding to Unicode.

NOTE: Binding of unicode output parameters is coded but untested.

NOTE: When building DBD::ODBC on Windows ($^O eq 'MSWin32') the WITH_UNICODE macro is automatically added. To disable specify -nou as an argument to Makefile.PL (e.g. nmake Makefile.PL -nou). On non-Windows platforms the WITH_UNICODE macro is not enabled by default and to enable you need to specify the -u argument to Makefile.PL. Please bare in mind that some ODBC drivers do not support SQL_Wxxx columns or parameters.

NOTE: Unicode support on Windows 64 bit platforms is currently untested. Let me know how you get on with it.

UNICODE support in ODBC Drivers differs considerably. Please read the README.unicode file for further details.

odbc_version

This was added prior to the move to ODBC 3.x to allow the caller to "force" ODBC 3.0 compatibility. It's probably not as useful now, but it allowed get_info and get_type_info to return correct/updated information that ODBC 2.x didn't permit/provide. Since DBD::ODBC is now 3.x, this can be used to force 2.x behavior via something like: my

  $dbh = DBI->connect("dbi:ODBC:$DSN", $user, $pass,
                      { odbc_version =>2});

Private statement attributes

odbc_more_results

Use this attribute to determine if there are more result sets available. SQL Server supports this feature. Use this as follows:

do { my @row; while (@row = $sth->fetchrow_array()) { # do stuff here } } while ($sth->{odbc_more_results});

Note that with multiple result sets and output parameters (i.e. using bind_param_inout, don't expect output parameters to be bound until ALL result sets have been retrieved.

Private DBD::ODBC Functions

You use DBD::ODBC private functions like this:

  $dbh->func(arg, private_function_name);

GetInfo

This private function is now superceded by DBI's get_info method.

This function maps to the ODBC SQLGetInfo call and the argument should be a valid ODBC information type (see ODBC specification). e.g.

  $value = $dbh->func(6, 'GetInfo');

which returns the SQL_DRIVER_NAME.

This function returns a scalar value, which can be a numeric or string value depending on the information value requested.

SQLGetTypeInfo

This private function is now superceded by DBI's type_info and type_info_all methods.

This function maps to the ODBC SQLGetTypeInfo API and the argument should be a SQL type number (e.g. SQL_VARCHAR) or SQL_ALL_TYPES. SQLGetTypeInfo returns information about a data type supported by the data source.

e.g.

  use DBI qw(:sql_types);

  $sth = $dbh->func(SQL_ALL_TYPES, GetTypeInfo);
  DBI::dump_results($sth);

This function returns a DBI statement handle for the SQLGetTypeInfo result-set containing many columns of type attributes (see ODBC specification).

NOTE: It is VERY important that the use DBI includes the qw(:sql_types) so that values like SQL_VARCHAR are correctly interpreted. This "imports" the sql type names into the program's name space. A very common mistake is to forget the qw(:sql_types) and obtain strange results.

GetFunctions

This function maps to the ODBC SQLGetFunctions API which returns information on whether a function is supported by the ODBC driver.

The argument should be SQL_API_ALL_FUNCTIONS (0) for all functions or a valid ODBC function number (e.g. SQL_API_SQLDESCRIBEPARAM which is 58). See ODBC specification or examine your sqlext.h and sql.h header files for all the SQL_API_XXX macros.

If called with SQL_API_ALL_FUNCTIONS (0), then a 100 element array is returned where each element will contain a '1' if the ODBC function with that SQL_API_XXX index is supported or '' if it is not.

If called with a specific SQL_API_XXX value for a single function it will return true if the ODBC driver supports that function, otherwise false.

e.g.

    my @x = $dbh->func(0,"GetFunctions");
    print "SQLDescribeParam is supported\n" if ($x[58]);

or

    print "SQLDescribeParam is supported\n"
        if $dbh->func(58, "GetFunctions");

GetStatistics

See the ODBC specification for the SQLStatistics API. You call SQLStatistics like this:

  $dbh->func($catalog, $schema, $table, $unique, 'GetStatistics');

GetForeignKeys

This private function is now superceded by DBI's foreign_key_info method.

See the ODBC specification for the SQLForeignKeys API. You call SQLForeignKeys like this:

  $dbh->func($pcatalog, $pschema, $ptable,
             $fcatalog, $fschema, $ftable,
             "GetForeignKeys");
 

GetPrimaryKeys

This private function is now superceded by DBI's primary_key_info method.

See the ODBC specification for the SQLPrimaryKeys API. You call SQLPrimaryKeys like this:

  $dbh->func($vatalog, $schema, $table, "GetPrimaryKeys");

data_sources

This private function is now superceded by DBI's data_sources method.

You call data_sources like this:

  @dsns = $dbh->func("data_sources);

Handled since 0.21.

GetSpecialColumns

See the ODBC specification for the SQLSpecialColumns API. You call SQLSpecialColumns like this:

  $dbh->func($identifier, $catalog, $schema, $table, $scope,
             $nullable, 'GetSpecialColumns');

Handled as of version 0.28

head3 ColAttributes

This private function is now superceded by DBI's statement attributes NAME, TYPE, PRECISION, SCLARE, NULLABLE etc).

See the ODBC specification for the SQLColAttributes API. You call SQLColAttributes like this:

  $dbh->func($column, $ftype, "ColAttributes");

head3 DescribeCol

This private function is now superceded by DBI's statement attributes NAME, TYPE, PRECISION, SCLARE, NULLABLE etc).

See the ODBC specification for the SQLDescribeCol API. You call SQLDescribeCol like this:

  @info = $dbh->func($column, "DescribeCol");

The returned array contains the column attributes in the order described in the ODBC specification for SQLDescribeCol.

Others/todo?

Level 1

    SQLTables (use tables()) call

Level 2

    SQLColumnPrivileges
    SQLProcedureColumns
    SQLProcedures
    SQLTablePrivileges
    SQLDrivers
    SQLNativeSql

Connect without DSN

The ability to connect without a full DSN is introduced in version 0.21.

Example (using MS Access): my $DSN = 'driver=Microsoft Access Driver (*.mdb);dbq=\\\\cheese\\g$\\perltest.mdb'; my $dbh = DBI->connect("dbi:ODBC:$DSN", '','') or die "$DBI::errstr\n";

Using DBD::ODBC with web servers under Win32.

General Commentary re web database access

This should be a DBI faq, actually, but this has somewhat of an Win32/ODBC twist to it.

Typically, the Web server is installed as an NT service or a Windows 95/98 service. This typically means that the web server itself does not have the same environment and permissions the web developer does. This situation, of course, can and does apply to Unix web servers. Under Win32, however, the problems are usually slightly different.

Defining your DSN -- which type should I use?

Under Win32 take care to define your DSN as a system DSN, not as a user DSN. The system DSN is a "global" one, while the user is local to a user. Typically, as stated above, the web server is "logged in" as a different user than the web developer. This helps cause the situation where someone asks why a script succeeds from the command line, but fails when called from the web server.

Defining your DSN -- careful selection of the file itself is important!

For file based drivers, rather than client server drivers, the file path is VERY important. There are a few things to keep in mind. This applies to, for example, MS Access databases.

1) If the file is on an NTFS partition, check to make sure that the Web service user has permissions to access that file.

2) If the file is on a remote computer, check to make sure the Web service user has permissions to access the file.

3) If the file is on a remote computer, try using a UNC path the file, rather than a X:\ notation. This can be VERY important as services don't quite get the same access permissions to the mapped drive letters and, more importantly, the drive letters themselves are GLOBAL to the machine. That means that if the service tries to access Z:, the Z: it gets can depend upon the user who is logged into the machine at the time. (I've tested this while I was developing a service -- it's ugly and worth avoiding at all costs).

Unfortunately, the Access ODBC driver that I have does not allow one to specify the UNC path, only the X:\ notation. There is at least one way around that. The simplest is probably to use Regedit and go to (assuming it's a system DSN, of course) HKEY_LOCAL_USERS\SOFTWARE\ODBC\"YOUR DSN" You will see a few settings which are typically driver specific. The important value to change for the Access driver, for example, is the DBQ value. That's actually the file name of the Access database.

Connect without DSN

The ability to connect without a full DSN is introduced in version 0.21.

Example (using MS Access): my $DSN = 'driver=Microsoft Access Driver (*.mdb);dbq=\\\\cheese\\g$\\perltest.mdb'; my $dbh = DBI->connect("dbi:ODBC:$DSN", '','') or die "$DBI::errstr\n";

The above sample uses Microsoft's UNC naming convention to point to the MSAccess file (\\\\cheese\\g$\\perltest.mdb). The dbq parameter tells the access driver which file to use for the database.

Example (using MSSQL Server): my $DSN = 'driver={SQL Server};Server=server_name; database=database_name;uid=user;pwd=password;'; my $dbh = DBI->connect("dbi:ODBC:$DSN") or die "$DBI::errstr\n";

These are in need of sorting and annotating. Some are relevant only to ODBC developers.

http://www.syware.com

http://www.microsoft.com/odbc

For Linux/Unix folks, compatible ODBC driver managers can be found at:

http://www.unixodbc.org (unixODBC source and rpms)

http://www.iodbc.org (iODBC driver manager source)

For Linux/Unix folks, you can checkout the following for ODBC Drivers and Bridges:

http://www.easysoft.com

http://www.openlinksw.com

http://www.datadirect.com

http://www.atinet.com/support/openrda_samples.asp

Some useful tutorials:

Debugging Perl DBI:

http://www.easysoft.com/developer/languages/perl/dbi-debugging.html

Enabling ODBC support in Perl with Perl DBI and DBD::ODBC:

http://www.easysoft.com/developer/languages/perl/dbi_dbd_odbc.html

Perl DBI/DBD::ODBC Tutorial Part 1 - Drivers, Data Sources and Connection:

http://www.easysoft.com/developer/languages/perl/dbd_odbc_tutorial_part_1.html

Perl DBI/DBD::ODBC Tutorial Part 2 - Introduction to retrieving data from your database:

http://www.easysoft.com/developer/languages/perl/index.html

Perl DBI/DBD::ODBC Tutorial Part 3 - Connecting Perl on UNIX or Linux to Microsoft SQL Server:

http://www.easysoft.com/developer/languages/perl/sql_server_unix_tutorial.html

Perl DBI - Put Your Data On The Web:

http://www.easysoft.com/developer/languages/perl/tutorial_data_web.html

Frequently Asked Questions

Answers to common DBI and DBD::ODBC questions:

How do I read more than N characters from a Memo | BLOB | LONG field?

See LongReadLen in the DBI docs.

Example:

 $dbh->{LongReadLen} = 20000;
 $sth = $dbh->prepare("select long_col from big_table");
 $sth->execute;
 etc
What is DBD::ODBC?
Why can't I connect?
Do I need an ODBC driver?
What is the ODBC driver manager?

These, general questions lead to needing definitions.

ODBC Driver

The ODBC Driver is the driver that the ODBC manager uses to connect and interact with the RDBMS. You DEFINITELY need this to connect to any database. For Win32, they are plentiful and installed with many applications. For Linux/Unix, you can find a fairly comprehensive list at http://www.unixodbc.org/drivers.html.

ODBC Driver Manager

The ODBC driver manager is the interface between an ODBC application (DBD::ODBC in this case) and the ODBC driver. The driver manager principally provides the ODBC API so ODBC applications may link with a single shared object (or dll) and be able to talk to a range of ODBC drivers. At run time the application provides a connection string which defines the ODBC data source it wants to connect to and this in turn defines the ODBC driver which will handle this data source. The driver manager loads the requested ODBC driver and passes all ODBC API calls on to the driver. In this way, an ODBC application can be built and distributed without knowing which ODBC driver it will be using.

However, this is a rather simplistic description of what the driver manager does. The ODBC driver manager also:

* Controls a repository of installed ODBC drivers (on UNIX this is the file odbcinst.ini).

* Controls a repository of defined ODBC data sources (on UNIX these are the files odbc.ini and .odbc.ini).

* Provides the ODBC driver APIs (SQLGetPrivateProfileString and SQLWritePrivateProfileString) to read and write ODBC data source attributes.

* Handles ConfigDSN which the driver exports to configure data sources.

* Provides APIs to install and uninstall drivers (SQLInstallDriver).

* Maps ODBC versions e.g. so an ODBC 2.0 application can work with an ODBC 3.0 driver and vice versa.

* Maps ODBC states between different versions of ODBC.

* Provides a cursor library for drivers which only support forward-only cursors.

* Provides SQLDataSources and SQLDrivers so an application can find out what ODBC drivers are installed and what ODBC data sources are defined.

* Provides an ODBC administrator which driver writers can use to install ODBC drivers and users can use to define ODBC data sources.

The ODBC Driver Manager is the piece of software which interacts with the drivers for the application. It "hides" some of the differences between the drivers (i.e. if a function call is not supported by a driver, it 'hides' that and informs the application that the call is not supported. DBD::ODBC needs this to talk to drivers.

Under Win32, you usually get the ODBC Driver Manager as part of the OS. Under Unix/Linux you may have to find and build the driver manager yourself. The two main driver managers for Unix are unixODBC (http://www.unixodbc.org) and iODBC (http://www.iodbc.org).

It is strongly advised you get an ODBC Driver Manager before trying to build DBD::ODBC unless you intend linking DBD::ODBC directly with your driver.

For a reasonable description of ODBC on Unix/Linux see http://www.easysoft.com/developer/interfaces/odbc/linux.html

DBD::ODBC

DBD::ODBC uses the driver manager to talk to the ODBC driver(s) on your system. You need both a driver manager and driver installed and tested before working with DBD::ODBC. You need to have a DSN (see below) configured and TESTED before being able to test DBD::ODBC.

DSN (Data Source Name)

The DSN is a way of referring to a particular driver and database by any name you wish. The DSN is usually a key to a list of attributes the ODBC driver needs to connect to the database (e.g. ip address and port) but there is always a key which names the driver so the driver manager knows which driver to use with which data source. Do no confuse DSNs with ODBC connection strings or DBI's "$data_source" (the first argument to "connect" in DBI.

The $data_source argument to DBI is composed of 'dbi:DRIVER:something_else' where DRIVER is the name of the DBD driver you want to use (ODBC of course for DBD::ODBC). The "something_else" for DBD::ODBC can be a DSN name or it can be a normal ODBC connection string.

An ODBC connection string consists of attribute/value pairs separated with semicolons (;). You can replace "something_else" above with a normal ODBC connection string but as a special case for DBD::ODBC you can just use the DSN name without the usual ODBC connection string prefix of "DSN=dsn_name".

e.g.

dbi:ODBC:DSN=fred

ODBC connection string using fred DSN

dbi:ODBC:fred

Same as above (a special case).

dbi:ODBC:Driver={blah blah driver};Host=1.2.3.4;Port=1000;

This is known as a DSN-less connection string for obvious reasons.

Where do I get an ODBC driver manager for Unix/Linux?

DBD::ODBC used to come bundled with a driver manager but this became inconvenient when the driver manager was updated.

The two main ODBC Driver Managers for Unix are unixODBC (http://www.unixodbc/org) and iODBC (http://www.iodbc.org).

If you are running a packaged Linux like RedHat, Ubuntu, Fedora, Suse etc etc you'll usually find it packaged with unixODBC and using the package manager to install it is fairly straight forward. However, make sure that if the driver manager is split into multiple packages you install the development package as well as that contains the C header files required by DBD::ODBC.

If you cannot find an ODBC Driver Manager package for your OS you can download the source tar files for either of the driver managers above and build it yourself.

How do I access a MS SQL Server database from Linux/UNIX?

You have loads of choices (in no particular order):

* using DBI::ProxyServer or DBD::Gofer. You'll need the former if you use transactions.

* using a commercial ODBC Driver or bridge like the ones from Easysoft or Openlink.

* using FreeTDS an open source TDS library which includes an ODBC Driver.

* using DBD::Sybase and Sybase libraries.

How do I access a MS-Access database from Linux?

There are basically two choices:

* a commercial ODBC Bridge like the ones from Easysoft or OpenLink.

* using mdbtools although as of writing it has not been updated since June 2004, only provides read access and seems to be a little buggy.

Almost all of my tests for DBD::ODBC fail. They complain about not being able to connect or the DSN is not found.

Please, please test your configuration of ODBC and driver before trying to test DBD::ODBC. Most of the time, this stems from the fact that the DSN (or ODBC) is not configured properly. unixODBC comes with a small program isql and iODBC comes with odbctest and you should use these to test your ODBC configuration is working properly first.

I'm attempting to bind a Long Var char (or other specific type) and the binding is not working.

The code I'm using is below:

        $sth->bind_param(1, $str, $DBI::SQL_LONGVARCHAR);
                                 ^^^

The problem is that DBI::SQL_LONGVARCHAR is not the same as $DBI::SQL_LONGVARCHAR and that $DBI::SQL_LONGVARCHAR is an error!

It should be:

        $sth->bind_param(1, $str, DBI::SQL_LONGVARCHAR);
Does DBD::ODBC support Multiple Active Statements?

Multiple Active Statements (MAS) are concurrent statements created from the same database handle which both have pending actions on them (e.g. they both have executed a select statement but not retrieved all the available rows yet).

DBD::ODBC does support MAS but whether you can actually use MAS is down to the ODBC Driver.

By default MS SQL Server did not used to support multiple active statements if any of them were select statements. You could get around this (with caution) by changing to a dynamic cursor. There is a "hack" in DBD::ODBC which can be used to enable MAS but you have to fully understand the implications of doing so(see "ODBC/odbc_SQL_ROWSET_SIZE" in DBD and "ODBC/odbc_cursortype" in DBD).

In MS SQL Server 2005, there is a new thing called MARS (Multiple Active Result Sets) which allows multiple active select statements but it has some nasty implications it you are also doing transactions.

For other drivers it depends. I believe various Oracle ODBC drivers doe support multiple active statements as myodbc does.

Think carefully before using multiple active statements. It is probably not portable and there is nearly always a better way of doing it.

If anyone wants to report success with a particular driver and multiple active statements I will collect them here.

Why do I get "Datetime field overflow" when attempting to insert a date into Oracle?

If you are using the Oracle or Microsoft ODBC drivers then you may get the following error when inserting dates into an Oracle database:

  [Oracle][ODBC]Datetime field overflow. (SQL-22008)

If you do then check v$nls_parameters and v$parameter to see if you are using a date format containing the RR format. e.g.,

  select * from v$nls_parameters where parameter = 'NLS_DATE_FORMAT'
  select * from v$parameter where name = 'nls_date_format'

If you see a date format like 'DD-MON-RR' (e.g., contains an RR) then all I can suggest is you change the date format for your session as I have never been able to bind a date using this format. You can do this with:

  alter session set nls_date_format='YYYY/MM/DD'

and use any format you like but keep away from 'RR'.

You can find some test code in the file mytest/rtcpan_28821.pl which demonstrates this problem. This was originally a rt.cpan issue which can be found at http://rt.cpan.org/Ticket/Display.html?id=28821.

As an aside, if anyone is reading this and can shed some light on the problem I'd love to hear from you. The technical details are:

  create table rtcpan28821 (a date)
  insert into rtcpan28821 values('23-MAR-62') fails

Looking at the ODBC trace, SQLDescribeParam returns:

  data type: 93, SQL_TYPE_TIMESTAMP
  size: 19
  decimal digits: 0
  nullable: 1

and DBD::ODBC calls SQLBindParameter with:

  ValueType: SQL_C_CHAR
  ParameterType: SQL_TYPE_TIMESTAMP
  ColumnSize: 9
  DecimalDigits: 0
  Data: 23-MAR-62
  BufferLength: 9
Why do my SQL Server temporary objects disappear?

If you are creating temporary objects (e.g., temporary tables) in SQL Server you find they have disappeared when you attempt to use them. Temporary objects only have a lifetime of the session they are created in but in addition, they cannot be created using prepare/execute. e.g., the following fails:

  $s = $h->prepare('select * into #tmp from mytable');
  $s->execute;
  $s = $h->selectall_arrayref('select * from #tmp');

with "Invalid object name '#tmp'". Your should read http://technet.microsoft.com/en-US/library/ms131667.aspx which basically says Prepared statements cannot be used to create temporary objects on SQL Server 2000 or later.... The proper way to avoid this is to use the do method but if you cannot do that then you need to add the "odbc_exec_direct" attribute to your prepare as follows:

  my $s = $h->prepare('select * into #tmp from mytable',
                      { odbc_exec_direct => 1});

See "odbc_exec_direct".

2 POD Errors

The following errors were encountered while parsing the POD:

Around line 980:

You forgot a '=back' before '=head2'

Around line 999:

=back without =over