NAME

       Alzabo::Runtime::UniqueRowCache - Implements a row cache for Alzabo

SYNOPSIS

         use Alzabo::Runtime::UniqueRowCache;

         Alzabo::Runtime::UniqueRowCache->clear();

DESCRIPTION

       This is a very simple caching mechanism for "Alzabo::Runtime::Row" objects that tries to
       ensure that for there is never more than one row object in memory for a given database
       row.

       To use it, simply load it.

       It can be foiled through the use of "Storable" or other "deep magic" cloning code, like in
       the "Clone" module.

       The cache is a simple hash kept in memory.  If you use this module, you are responsible
       for clearing the cache as needed.  The only time it is cleared automatically is when a
       table update or delete is performed, in which case all cached rows for that table are
       cleared.

       In a persistent environment like mod_perl, you should clear the cache on a regular basis
       in order to prevent the cache from getting out of sync with the database.  A good way to
       do this is to clear it at the start of every request.

METHODS

       All methods provided are class methods.

       •   clear

           This clears the entire cache

       •   clear_table( $table_object )

           Given a table object, this method clears all the cached rows from that table.

       •   row_in_cache( $table_name, $row_id )

           Given a table name and a row id, as returned by the
           "Alzabo::Runtime::Row->id_as_string" method, this method returns the matching row from
           the cache, if it exists.  Otherwise it returns undef.

       •   delete_from_cache( $table_name, $row_id )

           Given a table name and a row id, as returned by the
           "Alzabo::Runtime::Row->id_as_string" method, this method returns the matching row from
           the cache.

       •   write_to_cache( $row_object )

           Given a row object, this method stores it in the cache.

AVOIDING THE CACHE

       If you want to not cache a row, then you can pass the "no_cache" parameter to any table or
       schema method that creates a new row object or a cursor, such as
       "Alzabo::Runtime::Table->insert()", "Alzabo::Runtime::Table->rows_where()".

AUTHOR

       Dave Rolsky, <autarch@urth.org>