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DBI::DBD::Metadata(3) User Contributed Perl DocumentationDBI::DBD::Metadata(3)

NAME
       DBI::DBD::Metadata - Generate the code and data for some	DBI metadata
       methods

SYNOPSIS
       The idea	is to extract metadata information from	a good quality ODBC
       driver and use it to generate code and data to use in your own DBI
       driver for the same database.

       To generate code	to support the get_info	method:

	 perl -MDBI::DBD::Metadata -e "write_getinfo_pm('dbi:ODBC:dsn-name','user','pass','Driver')"

	 perl -MDBI::DBD::Metadata -e write_getinfo_pm dbi:ODBC:foo_db username	password Driver

       To generate code	to support the type_info method:

	 perl -MDBI::DBD::Metadata -e "write_typeinfo_pm('dbi:ODBC:dsn-name','user','pass','Driver')"

	 perl -MDBI::DBD::Metadata -e write_typeinfo_pm	dbi:ODBC:dsn-name user pass Driver

       Where "dbi:ODBC:dsn-name" is the	connection to use to extract the data,
       and "Driver" is the name	of the driver you want the code	generated for
       (the driver name	gets embedded into the output in numerous places).

Generating a GetInfo package for a driver
       The "write_getinfo_pm" in the DBI::DBD::Metadata	module generates a
       DBD::Driver::GetInfo package on standard	output.

       This method generates a DBD::Driver::GetInfo package from the data
       source you specified in the parameter list or in	the environment
       variable	DBI_DSN.  DBD::Driver::GetInfo should help a DBD author
       implement the DBI get_info() method.  Because you are just creating
       this package, it	is very	unlikely that DBD::Driver already provides a
       good implementation for get_info().  Thus you will probably connect via
       DBD::ODBC.

       Once you	are sure that it is producing reasonably sane data, you	should
       typically redirect the standard output to lib/DBD/Driver/GetInfo.pm,
       and then	hand edit the result.  Do not forget to	update your
       Makefile.PL and MANIFEST	to include this	as an extra PM file that
       should be installed.

       If you connect via DBD::ODBC, you should	use version 0.38 or greater;

       Please take a critical look at the data returned!  ODBC drivers vary
       dramatically in their quality.

       The generator assumes that most values are static and places these
       values directly in the %info hash.  A few examples show the use of CODE
       references and the implementation via subroutines.  It is very likely
       that you	will have to write additional subroutines for values depending
       on the session state or server version, e.g.  SQL_DBMS_VER.

       A possible implementation of DBD::Driver::db::get_info()	may look like:

	 sub get_info {
	   my($dbh, $info_type)	= @_;
	   require DBD::Driver::GetInfo;
	   my $v = $DBD::Driver::GetInfo::info{int($info_type)};
	   $v =	$v->($dbh) if ref $v eq	'CODE';
	   return $v;
	 }

       Please replace Driver (or "<foo>") with the name	of your	driver.	 Note
       that this stub function is generated for	you by write_getinfo_pm
       function, but you must manually transfer	the code to Driver.pm.

Generating a TypeInfo package for a driver
       The "write_typeinfo_pm" function	in the DBI::DBD::Metadata module
       generates on standard output the	data needed for	a driver's
       type_info_all method.  It also provides default implementations of the
       type_info_all method for	inclusion in the driver's main implementation
       file.

       The driver parameter is the name	of the driver for which	the methods
       will be generated; for the sake of examples, this will be "Driver".
       Typically, the dsn parameter will be of the form	"dbi:ODBC:odbc_dsn",
       where the odbc_dsn is a DSN for one of the driver's databases.  The
       user and	pass parameters	are the	other optional connection parameters
       that will be provided to	the DBI	connect	method.

       Once you	are sure that it is producing reasonably sane data, you	should
       typically redirect the standard output to lib/DBD/Driver/TypeInfo.pm,
       and then	hand edit the result if	necessary.  Do not forget to update
       your Makefile.PL	and MANIFEST to	include	this as	an extra PM file that
       should be installed.

       Please take a critical look at the data returned!  ODBC drivers vary
       dramatically in their quality.

       The generator assumes that all the values are static and	places these
       values directly in the %info hash.

       A possible implementation of DBD::Driver::type_info_all() may look
       like:

	 sub type_info_all {
	   my ($dbh) = @_;
	   require DBD::Driver::TypeInfo;
	   return [ @$DBD::Driver::TypeInfo::type_info_all ];
	 }

       Please replace Driver (or "<foo>") with the name	of your	driver.	 Note
       that this stub function is generated for	you by the write_typeinfo_pm
       function, but you must manually transfer	the code to Driver.pm.

AUTHORS
       Jonathan	Leffler	<jleffler@us.ibm.com> (previously
       <jleffler@informix.com>), Jochen	Wiedmann <joe@ispsoft.de>, Steffen
       Goeldner	<sgoeldner@cpan.org>, and Tim Bunce <dbi-users@perl.org>.

perl v5.24.1			  2015-05-26		 DBI::DBD::Metadata(3)

NAME | SYNOPSIS | Generating a GetInfo package for a driver | Generating a TypeInfo package for a driver | AUTHORS

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