NAME

DBD::ODBC - ODBC Driver for DBI

SYNOPSIS

  use DBI;

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

See DBI for more information.

DESCRIPTION

Recent Updates

 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.

DBD::ODBC 0.45_9

Fixed bug in procedure handling for SQLServer. Was not re-describing the result sets if the SQLMoreResults in the execute needs to be called.

DBD::ODBC 0.45_8

Fixed bug in tracing code when binding an undef parameter which did not happen to have a valid buffer with tracing level >= 2

Fixed bug when binding undef after a valid data bind on a timestamp. The Scale value was being calculated based upon the string that had been bound prior to the bind of the undef and if that had a sub-second value, then the scale would be set to the wrong value... I.e. bind_param(1, '2000-05-17 00:01:00.250', SQL_TYPE_TIMESTAMP) then execute bind_param(1, undef, SQL_TYPE_TIMESTAMP) then

Fixed SQL Server issue when binding a null and the length was set to 0 instead of 1

DBD::ODBC 0.45_7

Adding support for array binding, but not finished.

Fixed bug where SqlServer Stored procedures which perform INSERT would not correctly return a result set. Thanks to Joe Tebelskis for finding it and Martin Evans for supplying a fix.

Fixed bug where binding the empty string would cuase a problem. Fixed and added test in t/07bind.t.

DBD::ODBC 0.45_6

Added support for new DBI ParamValues feature.

DBD::ODBC 0.45_5

Added odbc_err_handler and odbc_async_exec thanks to patches by David L. Good. See example in mytest/testerrhandler.pl

Here's the notes about it:

> I've implemented two separate functions. The first is an "error > handler" similar to that in DBD::Sybase. The error handler can be used > to intercept error and status messages from the server. It is the only > way (at least currently) that you can retrieve non-error status messages > when execution is successful. > > To use the error handler, set the "odbc_err_handler" attribute on > your database handle to a reference to a subroutine that will act > as the error handler. This subroutine will be passed two args, the > SQLSTATE and the error message. If the subroutine returns 0, the > error message will be otherwise ignored. If it returns non-zero, > the error message will be processed normally. > > The second function implemented is asynchronous execution. It's only > useful for retrieving server messages with an error handler during an > execute() that takes a long time (such as a DBCC on a large database) ODBC > doesn't have the concept of a callback routine like Sybase's DBlib/CTlib > does, so asynchronous execution is needed to be able to get the server > messages before the SQL statement is done processing. > > To use asynchronous execution, set the "odbc_async_exec" attribute on > your database handle to 1. Not all ODBC drivers support asynchronous > execution. To see if yours does, set odbc_async_exec to 1 and then check > it's value. If the value is 1, your ODBC driver can do asynchronous > execution. If the value is 0, your ODBC driver cannot.

DBD::ODBC 0.45_4

More fixes for DB2 tests and timestamp handling.

DBD::ODBC 0.45_3

Changes to internal timestamp type handling and test structure to ensure tests work for all platforms. DB2 was giving me fits due to bad assumptions. Thanks to Martin Evans (again) for help in identifying the problems and helping research solutions. This includes the scale/precision values to correctly store full timestamps.

DBD::ODBC 0.45_2

Moving API usage to ODBC 3.0 specifications. With lots of help from Martin Evans (again!). Thanks Martin!!!!!

DBD::ODBC 0.44

Fix for do() and execute to handle DB2 correctly. Patch/discovery thanks to Martin Evans. Partly moving towards defaulting to ODBC 3.x standards.

DBD::ODBC 0.43

Fix for FoxPro drivers -- HURRAY!!!!!!!!! Bad call to SQLDescribeCol where the FoxPro driver seems to clear out the buffer passed and the size of the buffer indicated in the parameters was larger than the real buffer...need better fix long term, but fixed for now by allocating extra space.

Added support for column_info (maps to function columns, previously provided)

Fix for binding undef value generated by a dereferencing an empty hash value. I.e in the hash, there is no key value "1", but $hash{"1"} is passed to binding parameters.

A fix to make all bound columns word aligned. This solved a problem on solaris when binding timestamp values after a varchar value. This patch forces all columns to start on word boundaries (sizeof int boundaries, actually). This may have a positive speed impact for other systems. Thanks to Joe Slagel for pointing this out and providing a patch for the fix!

DBD::ODBC 0.42

A patch to the tests to get past any potential problems with a user not defining the DBI_DSN environment variable. Hopefully this will allow ActiveState to keep up with DBD::ODBC in their automated builds. Thanks to Jan Dubois for helping me determine what the issue(s) may be when testing. Now skips all tests except the dll/so load if DBI_DSN is not defined. Also, issues a skip on a known Oracle ODBC test.

A patch to fix ping() when a S1000 was returned. I don't know how this one is going to go, but it's worth a shot. Now calls SQLTables with unlikely parameters. If SQLTables() succeeds and returns a result set, ping() will now return true. Thanks to Tim Bunce for the suggestion.

DBD::ODBC 0.41

A patch to handle SQLDescribeParam failing in some circumstances. I believe this is a bug in the ODBC driver, but this happens with SQL Server and INNER JOIN syntax queries, but not when where a.i = b.i. The behavior is now to revert to assume SQL_VARCHAR if SQLDescribeParam fails for whatever reason.

Added warning during tests when the Oracle ODBC driver is detected and it is a known error. I didn't want to make it pass the test silently, but I did want to print a message indicating it was expected.

DBD::ODBC 0.40

Two minor patches for building. One for Cygwin support and another to handle the case where both iODBC and unixODBC libraries are installed. The preference is now given to unixODBC...

Fixed problem in connect code introduced in 0.39 where new code would only be executed if tracing was on and > 3...

NEW: Changed default bind type to 0, to let DBD::ODBC try to detect the correct bind type. This is a potentially significant change. Please let me know if there is a problem. The best way is to post a message to the dbi-users@perl.org mailing list.

DBD::ODBC 0.39

 Removing iodbcsrc directory as newer/better versions
 can be found on the web at www.iodbc.org and
 www.unixodbc.org.  On Linux, I currently build
 with unixODBC verson 2.2.0.
 
 Added patch for handling setting the ODBC environment
 during the connect, thanks to Steffen Goeldner
 
 The attached patch makes it possible to choose the
 ODBC version. E.g.:
 
   my $dbh = DBI->connect( ..., { odbc_version => 3 } )
 
 directs the driver to exhibit ODBC 3.x behavior.

 Fix to SQLColAttributes thanks to Nicolas DeRico

 Changes to the connect sequence.  If SQLDriverConnect
 is supported and fails, SQLConnect will be called
 I<unless> (this is the new part) the length of the
 DSN is > SQL_MAX_DSN_LENGTH or the DSN begins with
 DSN=

 New test in mytest which demonstrates long binary
 types.  If you are having trouble inserting images
 into your database, please check here.
=item B<DBD::ODBC 0.38>

 Fixed do function (again) thanks to work by Martin Evans.
 

DBD::ODBC 0.37

 Patches for get_info where return type is string.  Patches
 thanks to Steffen Goldner.  Thanks Steffen!

 Patched get_info to NOT attempt to get data for SQL_DRIVER_HSTMT
 and SQL_DRIVER_HDESC as they expect data in and have limited value
 (IMHO).

DBD::ODBC 0.37

 Further fixed build for ODBC 2.x drivers.  The new SQLExecDirect
 code had SQLAllocHandle which is a 3.x function, not a 2.x function.
 Sigh.  I should have caught that the first time.  Signed, the Mad-and-
 not-thorough-enough-patcher.

 Additionally, a random core dump occurred in the tests, based upon the
 new SQLExecDirect code.  This has been fixed.
 
 

DBD::ODBC 0.36

 Fixed build for ODBC 2.x drivers.  The new SQLExecDirect code
 had SQLFreeHandle which is a 3.x function, not a 2.x function.
 

DBD::ODBC 0.35

 Fixed (finally) multiple result sets with differing
 numbers of columns.  The final fix was to call
 SQLFreeStmt(SQL_UNBIND) before repreparing
 the statement for the next query.

 Added more to the multi-statement tests to ensure
 the data retrieved was what was expected.

 Now, DBD::ODBC overrides DBI's do to call SQLExecDirect
 for simple statements (those without parameters).
 Please advise if you run into problems.  Hopefully,
 this will provide some small speed improvement for
 simple "do" statements.  You can also call
 $dbh->func($stmt, ExecDirect).  I'm not sure this has
 great value unless you need to ensure SQLExecDirect
 is being called.  Patches thanks to Merijn Broeren.
 Thanks Merijn!
   

DBD::ODBC 0.34

 Further revamped tests to attempt to determine if SQLDescribeParam
 will work to handle the binding types.  The t/08bind.t attempts
 to determine if SQLDescribeParam is supported.  note that Oracle's
 ODBC driver under NT doesn't work correctly when binding dates
 using the ODBC date formatting {d } or {ts }.  So, test #3 will
 fail in t/08bind.t

 New support for primary_key_info thanks to patches by Martin Evans.
 New support for catalog, schema, table and table_type in table_info
 thanks to Martin Evans.  Thanks Martin for your work and your
 continuing testing, suggestions and general support!

 Support for upcoming dbi get_info.
 

DBD::ODBC 0.33_3

 Revamped tests to include tests for multiple result sets.
 The tests are ODBC driver platform specific and will be skipped
 for drivers which do not support multiple result sets.
 

DBD::ODBC 0.33_2

 Finally tested new binding techniques with SQL Server 2000,
 but there is a nice little bug in their MDAC and ODBC
 drivers according to the knowledge base article # Q273813, titled

   "FIX: "Incorrect Syntax near the Keyword 'by' "
   Error Message with Column Names of "C", "CA" or "CAS" (Q273813)

 DBD::ODBC now does not name any of the columns A, B, C, or D
 they are now COL_A, COL_B, COL_C, COL_D.

 *** NOTE: *** I AM STRONGLY CONSIDERING MAKING THE NEW
 BINDING the default for future versions.  I do not believe
 it will break much existing code (if any) as anyone binding
 to non VARCHAR (without the ODBC driver doing a good conversion
 from the VARCHAR) will have a problem.  It may be subtle, however,
 since much code will work, but say, binding dates may not with
 some drivers.
   
 Please comment soon...
   

DBD::ODBC 0.33_1

*** WARNING: ***

 Changes to the binding code to allow the use of SQLDescribeParam
 to determine if the type of column being bound.  This is
 experimental and activated by setting
 
  $dbh->{odbc_default_bind_type} = 0; # before creating the query...

 Currently the default value of odbc_default_bind_type = SQL_VARCHAR
 which mimicks the current behavior.  If you set
 odbc_default_bind_type to 0, then SQLDescribeParam will be
 called to determine the columen type.  Not ALL databases
 handle this correctly.  For example, Oracle returns
 SQL_VARCHAR for all types and attempts to convert to the
 correct type for us.  However, if you use the ODBC escaped
 date/time format such as: {ts '1998-05-13 00:01:00'} then
 Oracle complains.  If you bind this with a SQL_TIMESTAMP type,
 however, Oracle's ODBC driver will parse the time/date correctly.
 Use at your own risk!

 Fix to dbdimp.c to allow quoted identifiers to begin/end
 with either " or '.
 The following will not be treated as if they have a bind placeholder:
   "isEstimated?"
   '01-JAN-1987 00:00:00'
   'Does anyone insert a ?'

                                    

DBD::ODBC 0.32

 More SAP patches to Makfile.PL to eliminate the call to Data Sources

 A patch to the test (for SAP and potentially others), to allow
 fallback to SQL_TYPE_DATE in the tests
 

DBD::ODBC 0.31

 Added SAP patches to build directly against SAP driver instead of
 driver manager thanks to Flemming Frandsen (thanks!)

 Added support to fix ping for Oracle8.  May break other databases,
 so please report this as soon as possible.  The downside is that
 we need to actually execute the dummy query.
 

DBD::ODBC 0.30

 Added ping patch for Solid courtesy of Marko Asplund

 Updated disconnect to rollback if autocommit is not on.
 This should silence some errors when disconnecting.

 Updated SQL_ROWSET_SIZE attribute.  Needed to force it to
 odbc_SQL_ROWSET_SIZE to obey the DBI rules.

 Added odbc_SQL_DRIVER_ODBC_VER, which obtains the version of
 the Driver upon connect.  This internal capture of the version is
 a read-only attributed and is used during array binding of parameters.
 
 Added odbc_ignore_named_placeholders attribute to facilicate
 creating triggers within SAPDB and Oracle, to name two. The
 syntax in these DBs is to allow use of :old and :new to
 access column values before and after updates.  Example:

 $dbh->{odbc_ignore_named_placeholders} = 1; # set it for all future statements
                                          # ignores :foo, :new, etc, but not :1 or ?
 $dbh->do("create or replace etc :new.D = sysdate etc");
 

DBD::ODBC 0.29

 Cygwin patches from Neil Lunn (untested by me).  Thanks Neil!
 

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->{odbc_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 >

VMS and other patches from Martin Evans (thanks!)

[1] a fix for Makefile.PL to build DBD::ODBC on OpenVMS.

[2] fix trace message coredumping after SQLDriverConnect

[3] fix call to SQLCancel which fails to pass the statement handle properly.

[4] consume diagnostics after SQLDriverConnect/SQLConnect call or they remain until the next error occurs and it then looks confusing (this is due to ODBC spec for SQLError). e.g. test 02simple returns a data truncated error only now instead of all the informational diags that are left from the connect call, like the "database changed", "language changed" messages you get from MS SQL Server.

Replaced C++ style comments with C style to support more platforms more easily.

Fixed bug which use the single quote (') instead of a double quote (") for "literal" column names. This helped when having a colon (:) in the column name.

Fixed bug which would cause DBD::ODBC to core-dump (crash) if DBI tracing level was greater than 3.

Fixed problem where ODBC.pm would have "use of uninitialized variable" if calling DBI's type_info.

Fixed problem where ODBC.xs *may* have an overrun when calling SQLDataSources.

Fixed problem with DBI 1.14, where fprintf was being called instead of PerlIO_printf for debug information

Fixed problem building with unixODBC per patch from Nick Gorham

Added ability to bind_param_inout() via patches from Jeremy Cooper. Haven't figured out a good, non-db specific way to test. My current test platform attempts to determine the connected database type via ugly hacks and will test, if it thinks it can. Feel free to patch and send me something...Also, my current Oracle ODBC driver fails miserably and dies.

Updated t/02simple.t to not print an error, when there is not one.

DBD::ODBC 0.28

Added support for SQLSpecialColumns thanks to patch provided by Martin J. Evans [martin@easysoft.com]

Fixed bug introduced in 0.26 which was introduced of SQLMoreResults was not supported by the driver.

DBD::ODBC 0.27

Examined patch for ping method to repair problem reported by Chris Bezil. Thanks Chris!

Added simple test for ping method working which should identify this in the future.

DBD::ODBC 0.26

Put in patch for returning only positive rowcounts from dbd_st_execute. The original patch was submitted by Jon Smirl and put back in by David Good. Reasoning seems sound, so I put it back in. However, any databases that return negative rowcounts for specific reasons, will no longer do so.

Put in David Good's patch for multiple result sets. Thanks David! See mytest\moreresults.pl for an example of usage.

Added readme.txt in iodbcsrc explaining an issue there with iODBC 2.50.3 and data_sources.

Put in rudimentary cancel support via SQLCancel. Call $sth->cencel to utilize. However, it is largely untested by me, as I do not have a good sample for this yet. It may come in handy with threaded perl, someday or it may work in a signal handler.

DBD::ODBC 0.25

Added conditional compilation for SQL_WVARCHAR and SQL_WLONGVARCHAR. If they are not defined by your driver manager, they will not be compiled in to the code. If you would like to support these types on some platforms, you may be able to #define SQL_WVARCHAR (-9) #define SQL_WLONGVARCHAR (-10)

Added more long tests with binding in t\09bind.t. Note use of bind_param!

DBD::ODBC 0.24

Fixed Test #13 in 02simple.t. Would fail, improperly, if there was only one data source defined.

Fixed (hopefully) SQL Server 7 and ntext type "Out of Memory!" errors via patch from Thomas Lowery. Thanks Thomas!

Added more support for Solid to handle the fact that it does not support data_sources nor SQLDriverConnect. Patch supplied by Samuli Karkkainen [skarkkai@woods.iki.fi]. Thanks! It's untested by me, however.

Added some information from Adam Curtin about a bug in iodbc 2.50.3's data_sources. See iodbcsrc\readme.txt.

Added information in this pod from Stephen Arehart regarding DSNLess connections.

Added fix for sp_prepare/sp_execute bug reported by Paul G. Weiss.

Added some code for handling a hint on disconnect where the user gets an error for not committing.

DBD::ODBC 0.22

Fixed for threaded perl builds. Note that this was tested only on Win32, with no threads in use and using DBI 1.13. Note, for ActiveState/PERL_OBJECT builds, DBI 1.13_01 is required as of 9/8/99. If you are using ActiveState's perl, this can be installed by using PPM.

DBD::ODBC 0.21

Thanks to all who provided patches!

Added ability to connect to an ODBC source without prior creation of DSN. See mytest/contest.pl for example with MS Access. (Also note that you will need documentation for your ODBC driver -- which, sadly, can be difficult to find).

Fixed case sensitivity in tests.

Hopefully fixed test #4 in t/09bind.t. Updated it to insert the date column and updated it to find the right type of the column. However, it doesn't seem to work on my Linux test machine, using the OpenLink drivers with MS-SQL Server (6.5). It complains about binding the date time. The same test works under Win32 with SQL Server 6.5, Oracle 8.0.3 and MS Access 97 ODBC drivers. Hmmph.

Fixed some binary type issues (patches from Jon Smirl)

Added SQLStatistics, SQLForeignKeys, SQLPrimaryKeys (patches from Jon Smirl) Thanks (again), Jon, for providing the build_results function to help reduce duplicate code!

Worked on LongTruncOk for Openlink drivers.

Note: those trying to bind variables need to remember that you should use the following syntax:

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

Added support for unixodbc (per Nick Gorham) Added support for OpenLinks udbc (per Patrick van Kleef) Added Support for esodbc (per Martin Evans) Added Support for Easysoft (per Bob Kline)

Changed table_info to produce a list of views, too. Fixed bug in SQLColumns call. Fixed blob handling via patches from Jochen Wiedmann. Added data_sources capability via snarfing code from DBD::Adabas (Jochen Wiedmann)

DBD::ODBC 0.20

SQLColAttributes fixes for SQL Server and MySQL. Fixed tables method by renaming to new table_info method. Added new tyoe_info_all method. Improved Makefile.PL support for Adabase.

DBD::ODBC 0.19

Added iODBC source code to distribution.Fall-back to using iODBC header files in some cases.

DBD::ODBC 0.18

Enhancements to build process. Better handling of errors in error handling code.

DBD::ODBC 0.17

This release is mostly due to the good work of Jeff Urlwin. My eternal thanks to you Jeff.

Fixed "SQLNumResultCols err" on joins and 'order by' with some drivers (see Microsoft Knowledge Base article #Q124899). Thanks to Paul O'Fallon for that one.

Added more (probably incomplete) support for unix ODBC in Makefile.PL

Increased default SQL_COLUMN_DISPLAY_SIZE and SQL_COLUMN_LENGTH to 2000 for drivers that don't provide a way to query them dynamically. Was 100!

When fetch reaches the end-of-data it automatically frees the internal ODBC statement handle and marks the DBI statement handle as inactive (thus an explicit 'finish' is *not* required).

Also:

  LongTruncOk for Oracle ODBC (where fbh->datalen < 0)
  Added tracing into SQLBindParameter (help diagnose oracle odbc bug)
  Fixed/worked around bug/result from Latest Oracle ODBC driver where in
     SQLColAttribute cbInfoValue was changed to 0 to indicate fDesc had a value
  Added work around for compiling w/ActiveState PRK (PERL_OBJECT)
  Updated tests to include date insert and type
  Added more "backup" SQL_xxx types for tests                                  
  Updated bind test to test binding select
  NOTE: bind insert fails on Paradox driver (don't know why)

Added support for: (see notes below)

  SQLGetInfo       via $dbh->func(xxx, GetInfo)
  SQLGetTypeInfo   via $dbh->func(xxx, GetTypeInfo)
  SQLDescribeCol   via $sth->func(colno, DescribeCol)
  SQLColAttributes via $sth->func(xxx, colno, ColAttributes)
  SQLGetFunctions  via $dbh->func(xxx, GetFunctions)
  SQLColumns       via $dbh->func(catalog, schema, table, column, 'columns')

Fixed $DBI::err to reflect the real ODBC error code which is a 5 char code, not necessarily numeric.

Fixed fetches when LongTruncOk == 1.

Updated tests to pass more often (hopefully 100% <G>)

Updated tests to test long reading, inserting and the LongTruncOk attribute.

Updated tests to be less driver specific.

They now rely upon SQLGetTypeInfo heavily in order to create the tables. The test use this function to "ask" the driver for the name of the SQL type to correctly create long, varchar, etc types. For example, in Oracle the SQL_VARCHAR type is VARCHAR2, while MS Access uses TEXT for the SQL Name. Again, in Oracle the SQL_LONGVARCHAR is LONG, while in Access it's MEMO. The tests currently handle this correctly (at least with Access and Oracle, MS SQL server will be tested also).

Private functions for ODBC API access

It is anticipated that at least some of the functions currently implemented via the func interface be "moved" into a more formal, DBI specification. This will be when the DBI specification supports/formalizes the meta-data to implement. Most of these functions are to obtain more information from the driver and the data source.

GetInfo

This function maps to the ODBC SQLGetInfo call. This is a Level 1 ODBC function. An example of this is:

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

This function returns a scalar value, which can be a numeric or string value. This depends upon the argument passed to GetInfo.

SQLGetTypeInfo

This function maps to the ODBC SQLGetTypeInfo call. This is a Level 1 ODBC function. An example of this is:

  use DBI qw(:sql_types);

  $sth = $dbh->func(SQL_ALL_TYPES, GetInfo);
  while (@row = $sth->fetch_row) {
    ...
  }

This function returns a DBI statement handle, which represents a result set containing type names which are compatible with the requested type. SQL_ALL_TYPES can be used for obtaining all the types the ODBC driver supports. 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 API SQLGetFunctions. This is a Level 1 API call which returns supported driver funtions. Depending upon how this is called, it will either return a 100 element array of true/false values or a single true false value. If it's called with SQL_API_ALL_FUNCTIONS (0), it will return the 100 element array. Otherwise, pass the number referring to the function. (See your ODBC docs for help with this).

SQLColumns

Support for this function has been added in version 0.17. It looks to be fixed in version 0.20.

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";

SQLStatistics

SQLForeignKeys

SQLPrimaryKeys

SQLDataSources

All handled, currently (as of 0.21)

SQLSpecialColumns

Handled as of version 0.28

Others/todo?

Level 1

    SQLTables (use tables()) call

Level 2

    SQLColumnPrivileges
    SQLProcedureColumns
    SQLProcedures
    SQLTablePrivileges
    SQLDrivers
    SQLNativeSql

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";

Random Links

These are in need of sorting and annotating. Some are relevant only to ODBC developers (but I don't want to loose them).

        http://www.ids.net/~bjepson/freeODBC/index.html

        http://dataramp.com/

        http://www.syware.com

        http://www.microsoft.com/odbc

   For Linux/Unix folks, compatible ODBC driver managers can be found at:
   
        http://www.easysoft.com         unixODBC driver manager source
                                        *and* ODBC-ODBC bridge for accessing Win32 ODBC sources from Linux

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

   Also, for Linux folks, you can checkout the following for another ODBC-ODBC bridge and support for iODBC.

        http://www.openlink.co.uk 
                or
        http://www.openlinksw.com 

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.

1) ODBC Driver - 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, some hunting is required, but you may find something useful at:

        http://www.openlinksw.com
        http://www.easysoft.com
        http://www.intersolv.com
              

2) ODBC Driver Manager - 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, it is built in to the OS. Under Unix/Linux, in most cases, you will want to use freeODBC, unixODBC or iODBC. iODBC was bundled with DBD::ODBC, but you will need to find one which suits your needs. Please see www.openlinksw.com, www.easysoft.com or www.iodbc.org

3) 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.

4) DSN -- Data Source Name. It's a way of referring to a particular database by any name you wish. The name itself can be configured to hide the gory details of which type of driver you need and the connection information you need to provide. For example, for some databases, you need to provide a TCP address and port. You can configure the DSN to have use information when you refer to the DSN.

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

DBD::ODBC comes with one (iODBC). In the DBD::ODBC source release is a directory named iodbcsrc. There are others. UnixODBC, FreeODBC and some of the drivers will come with one of these managers. For example Openlink's drivers (see below) come with the iODBC driver manager. Easysoft supplies both ODBC-ODBC bridge software and unixODBC.

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

Try using drivers from http://www.openlinksw.com or www.easysoft.com The multi-tier drivers have been tested with Linux and Redhat 5.1.

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

I believe you can use the multi-tier drivers from http://www.openlinksw.com, however, I have not tested this. Also, I believe there is a commercial solution from http://www.easysoft.com. I have not tested this.

If someone does have more information, please, please send it to me and I will put it in this FAQ.

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. iODBC comes with a odbctest program. Please use it to verify connectivity.

For Unix -> Windows DB see Tom Lowery's write-up.

http://tlowery.hypermart.net/perl_dbi_dbd_faq.html#HowDoIAccessMSWindowsDB

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);