my $dbh = DBI->connect(...);
my $cache = CHI->new( driver => 'DBI', dbh => $dbh, );
OR
my $cache = CHI->new( driver => 'DBI', dbh => $dbh, dbh_ro => $dbh_ro, );
DESCRIPTION
This driver uses a database table to store the cache. The newest
versions of MySQL and SQLite work are known to work. Other RDBMSes
should work.
Why cache things in a database? Isn't the database what people are
trying to avoid with caches? This is often true, but a simple primary
key lookup is extremely fast in many databases and this provides a
shared cache that can be used when less reliable storage like memcached
is not appropriate. Also, the speed of simple lookups on MySQL when
accessed over a local socket is very hard to beat. DBI is fast.
ATTRIBUTES
namespace
The namespace you pass in will be appended to the `table_prefix' and
used as a table name. That means that if you don't specify a
namespace or table_prefix the cache will be stored in a table called
`chi_Default'.
table_prefix
This is the prefix that is used when building a table name. If you
want to just use the namespace as a literal table name, set this to
undef. Defaults to `chi_'.
dbh The main, or rw, DBI handle used to communicate with the db. If a
dbh_ro handle is defined then this handle will only be used for
writing.
This attribute can be set after object creation as well, so in a
persistent environment like mod_perl or FastCGI you may keep an
instance of the cache around and set the dbh on each request after
checking it with ping().
dbh_ro
The optional DBI handle used for read-only operations. This is to
support master/slave RDBMS setups.
sql_strings
Hashref of SQL strings to use in the different cache operations. The
strings are built depending on the RDBMS that dbh is attached to.
METHODS
BUILD
Standard issue Moose BUILD method. Used to build the sql_strings. If
the parameter `create_table' to `new()' was set to true, it will
attempt to create the db table. For Mysql and SQLite the statement
is "create if not exists..." so it's generally harmless.
fetch
store
remove
clear
get_keys
get_namespaces
Not supported at this time.
Authors
Original version by Justin DeVuyst and Perrin Harkins. Currently
maintained by Jonathan Swartz.
COPYRIGHT & LICENSE
Copyright (C) Justin DeVuyst
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
