Bio::DB::GFF::Adaptor:User:ContriBio::DB::GFF::Adaptor::dbi::caching_handle(3)NAMEBio::DB::GFF::Adaptor::dbi::caching_handle-- Cache for database
handles
SYNOPSIS
use Bio::DB::GFF::Adaptor::dbi::caching_handle;
$db = Bio::DB::GFF::Adaptor::dbi::caching_handle->new('dbi:mysql:test');
$sth = $db->prepare('select * from foo');
@h = $sth->fetch_rowarray;
$sth->finish
DESCRIPTION
This module handles a pool of database handles. It was motivated by
the MYSQL driver's {mysql_use_result} attribute, which dramatically
improves query speed and memory usage, but forbids additional query
statements from being evaluated while an existing one is in use.
This module is a plug-in replacement for vanilla DBI. It automatically
activates the {mysql_use_result} attribute for the mysql driver, but
avoids problems with multiple active statement handlers by creating new
database handles as needed.
USAGE
The object constructor is
Bio::DB::GFF::Adaptor::dbi::caching_handle->new(). This is called like
DBI->connect() and takes the same arguments. The returned object looks
and acts like a conventional database handle.
In addition to all the standard DBI handle methods, this package adds
the following:
dbi_quote
Title : dbi_quote
Usage : $string = $db->dbi_quote($sql,@args)
Function: perform bind variable substitution
Returns : query string
Args : the query string and bind arguments
Status : public
This method replaces the bind variable "?" in a SQL statement with
appropriately quoted bind arguments. It is used internally to handle
drivers that don't support argument binding.
do_query
Title : do_query
Usage : $sth = $db->do_query($query,@args)
Function: perform a DBI query
Returns : a statement handler
Args : query string and list of bind arguments
Status : Public
This method performs a DBI prepare() and execute(), returning a
statement handle. You will typically call fetch() of fetchrow_array()
on the statement handle. The parsed statement handle is cached for
later use.
debug
Title : debug
Usage : $debug = $db->debug([$debug])
Function: activate debugging messages
Returns : current state of flag
Args : optional new setting of flag
Status : public
attribute
Title : attribute
Usage : $value = $db->attribute(AttributeName , [$newvalue])
Function: get/set DBI::db handle attribute
Returns : current state of the attribute
Args : name of the attribute and optional new setting of attribute
Status : public
Under Bio::DB::GFF::Adaptor::dbi::caching_handle the DBI::db
attributes that are usually set using hashref calls are unavailable.
Use attribute() instead. For example, instead of:
$dbh->{AutoCommit} = 0;
use
$dbh->attribute(AutoCommit=>0);
BUGS
Report to the author.
SEE ALSO
DBI, Bio::DB::GFF, bioperl
AUTHOR
Lincoln Stein <lstein@cshl.org>.
Copyright (c) 2001 Cold Spring Harbor Laboratory.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.1Bio::DB::GFF::Adaptor::dbi::caching_handle(3)
