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DBIx::Class::Storage::User:ContributedBPe::Class::Storage::DBI::Sybase::ASE(3)

NAME
       DBIx::Class::Storage::DBI::Sybase::ASE -	Sybase ASE SQL Server support
       for DBIx::Class

SYNOPSIS
       This subclass supports DBD::Sybase for real (non-Microsoft) Sybase
       databases.

DESCRIPTION
       If your version of Sybase does not support placeholders,	then your
       storage will be reblessed to
       DBIx::Class::Storage::DBI::Sybase::ASE::NoBindVars.  You	can also
       enable that driver explicitly, see the documentation for	more details.

       With this driver	there is unfortunately no way to get the
       "last_insert_id"	without	doing a	"SELECT	MAX(col)". This	is done	safely
       in a transaction	(locking the table.) See "INSERTS WITH PLACEHOLDERS".

       A recommended connect_info setting:

	 on_connect_call => [['datetime_setup'], ['blob_setup',	log_on_update => 0]]

METHODS
   connect_call_blob_setup
       Used as:

	 on_connect_call => [ [	'blob_setup', log_on_update => 0 ] ]

       Does "$dbh->{syb_binary_images} = 1;" to	return "IMAGE" data as raw
       binary instead of as a hex string.

       Recommended.

       Also sets the "log_on_update" value for blob write operations. The
       default is 1, but 0 is better if	your database is configured for	it.

       See "Handling IMAGE/TEXT	data with
       syb_ct_get_data()/syb_ct_send_data()" in	DBD::Sybase.

   connect_call_datetime_setup
       Used as:

	 on_connect_call => 'datetime_setup'

       In connect_info to set:

	 $dbh->syb_date_fmt('ISO_strict'); # output fmt: 2004-08-21T14:36:48.080Z
	 $dbh->do('set dateformat mdy');   # input fmt:	 08/13/1979 18:08:55.080

       This works for both "DATETIME" and "SMALLDATETIME" columns, note	that
       "SMALLDATETIME" columns only have minute	precision.

Schema::Loader Support
       As of version 0.05000, DBIx::Class::Schema::Loader should work well
       with most versions of Sybase ASE.

FreeTDS
       This driver supports DBD::Sybase	compiled against FreeTDS
       (<http://www.freetds.org/>) to the best of our ability, however it is
       recommended that	you recompile DBD::Sybase against the Sybase Open
       Client libraries. They are a part of the	Sybase ASE distribution:

       The Open	Client FAQ is here:
       <http://www.isug.com/Sybase_FAQ/ASE/section7.html>.

       Sybase ASE for Linux (which comes with the Open Client libraries) may
       be downloaded here:
       <http://response.sybase.com/forms/ASE_Linux_Download>.

       To see if you're	using FreeTDS run:

	 perl -MDBI -le	'my $dbh = DBI->connect($dsn, $user, $pass); print $dbh->{syb_oc_version}'

       It is recommended to set	"tds version" for your ASE server to 5.0 in
       "/etc/freetds/freetds.conf".

       Some versions or	configurations of the libraries	involved will not
       support placeholders, in	which case the storage will be reblessed to
       DBIx::Class::Storage::DBI::Sybase::ASE::NoBindVars.

       In some configurations, placeholders will work but will throw implicit
       type conversion errors for anything that's not expecting	a string. In
       such a case, the	"auto_cast" option from
       DBIx::Class::Storage::DBI::AutoCast is automatically set, which you may
       enable on connection with connect_call_set_auto_cast.  The type info
       for the "CAST"s is taken	from the "data_type" in
       DBIx::Class::ResultSource definitions in	your Result classes, and are
       mapped to a Sybase type (if it isn't already) using a mapping based on
       SQL::Translator.

       In other	configurations,	placeholders will work just as they do with
       the Sybase Open Client libraries.

       Inserts or updates of TEXT/IMAGE	columns	will NOT work with FreeTDS.

INSERTS	WITH PLACEHOLDERS
       With placeholders enabled, inserts are done in a	transaction so that
       there are no concurrency	issues with getting the	inserted identity
       value using "SELECT MAX(col)", which is the only	way to get the
       "IDENTITY" value	in this	mode.

       In addition, they are done on a separate	connection so that it's
       possible	to have	active cursors when doing an insert.

       When using "DBIx::Class::Storage::DBI::Sybase::ASE::NoBindVars"
       transactions are	unnecessary and	not used, as there are no concurrency
       issues with "SELECT @@IDENTITY" which is	a session variable.

TRANSACTIONS
       Due to limitations of the TDS protocol and DBD::Sybase, you cannot
       begin a transaction while there are active cursors, nor can you use
       multiple	active cursors within a	transaction. An	active cursor is, for
       example,	a ResultSet that has been executed using "next"	or "first" but
       has not been exhausted or reset.

       For example, this will not work:

	 $schema->txn_do(sub {
	   my $rs = $schema->resultset('Book');
	   while (my $result = $rs->next) {
	     $schema->resultset('MetaData')->create({
	       book_id => $result->id,
	       ...
	     });
	   }
	 });

       This won't either:

	 my $first_row = $large_rs->first;
	 $schema->txn_do(sub { ... });

       Transactions done for inserts in	"AutoCommit" mode when placeholders
       are in use are not affected, as they are	done on	an extra database
       handle.

       Some workarounds:

       o   use DBIx::Class::Storage::DBI::Replicated

       o   connect another Schema

       o   load	the data from your cursor with "all" in	DBIx::Class::ResultSet

MAXIMUM	CONNECTIONS
       The TDS protocol	makes separate connections to the server for active
       statements in the background. By	default	the number of such connections
       is limited to 25, on both the client side and the server	side.

       This is a bit too low for a complex DBIx::Class application, so on
       connection the client side setting is set to 256	(see "maxConnect" in
       DBD::Sybase.) You can override it to whatever setting you like in the
       DSN.

       See
       <http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.ase_15.0.sag1/html/sag1/sag1272.htm>
       for information on changing the setting on the server side.

DATES
       See "connect_call_datetime_setup" to setup date formats for
       DBIx::Class::InflateColumn::DateTime.

LIMITED	QUERIES
       Because ASE does	not have a good	way to limit results in	SQL that works
       for all types of	queries, the limit dialect is set to GenericSubQ.

       Fortunately, ASE	and DBD::Sybase	support	cursors	properly, so when
       GenericSubQ is too slow you can use the software_limit
       DBIx::Class::ResultSet attribute	to simulate limited queries by
       skipping	over records.

TEXT/IMAGE COLUMNS
       DBD::Sybase compiled with FreeTDS will NOT allow	you to insert or
       update "TEXT/IMAGE" columns.

       Setting "$dbh->{LongReadLen}" will also not work	with FreeTDS use
       either:

	 $schema->storage->dbh->do("SET	TEXTSIZE $bytes");

       or

	 $schema->storage->set_textsize($bytes);

       instead.

       However,	the "LongReadLen" you pass in connect_info is used to execute
       the equivalent "SET TEXTSIZE" command on	connection.

       See "connect_call_blob_setup" for a connect_info	setting	you need to
       work with "IMAGE" columns.

BULK API
       The experimental	DBD::Sybase Bulk API support is	used for populate in
       void context, in	a transaction on a separate connection.

       To use this feature effectively,	use a large number of rows for each
       populate	call, eg.:

	 while (my $rows = $data_source->get_100_rows()) {
	   $rs->populate($rows);
	 }

       NOTE: the add_columns calls in your "Result" classes must list columns
       in database order for this to work. Also, you may have to unset the
       "LANG" environment variable before loading your app, as "BCP -Y"	is not
       yet supported in	DBD::Sybase .

       When inserting IMAGE columns using this method, you'll need to use
       "connect_call_blob_setup" as well.

COMPUTED COLUMNS
       If you have columns such	as:

	 created_dtm AS	getdate()

       represent them in your Result classes as:

	 created_dtm =>	{
	   data_type =>	undef,
	   default_value => \'getdate()',
	   is_nullable => 0,
	   inflate_datetime => 1,
	 }

       The "data_type" must exist and must be "undef". Then empty inserts will
       work on tables with such	columns.

TIMESTAMP COLUMNS
       "timestamp" columns in Sybase ASE are not really	timestamps, see:
       <http://dba.fyicenter.com/Interview-Questions/SYBASE/The_timestamp_datatype_in_Sybase_.html>.

       They should be defined in your Result classes as:

	 ts => {
	   data_type =>	'timestamp',
	   is_nullable => 0,
	   inflate_datetime => 0,
	 }

       The "<inflate_datetime =" 0>> is	necessary if you use
       DBIx::Class::InflateColumn::DateTime, and most people do, and still
       want to be able to read these values.

       The values will come back as hexadecimal.

TODO
       o   Transitions to AutoCommit=0 (starting a transaction)	mode by
	   exhausting any active cursors, using	eager cursors.

       o   Real	limits and limited counts using	stored procedures deployed on
	   startup.

       o   Blob	update with a LIKE query on a blob, without invalidating the
	   WHERE condition.

       o   bulk_insert using prepare_cached (see comments.)

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.

perl v5.32.0			  202DBIx::Class::Storage::DBI::Sybase::ASE(3)

NAME | SYNOPSIS | DESCRIPTION | METHODS | Schema::Loader Support | FreeTDS | INSERTS WITH PLACEHOLDERS | TRANSACTIONS | MAXIMUM CONNECTIONS | DATES | LIMITED QUERIES | TEXT/IMAGE COLUMNS | BULK API | COMPUTED COLUMNS | TIMESTAMP COLUMNS | TODO | FURTHER QUESTIONS? | COPYRIGHT AND LICENSE

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