Programming the Perl DBI

Batch Fetching

Batch fetching is the ability to fetch the entire result set from an SQL query in one call, as opposed to iterating through the result set using row-oriented methods such as fetchrow_array( ), etc.

The DBI defines several methods for this purpose, including fetchall_arrayref( ) and selectall_arrayref( ) , which basically retrieve the entire result set into a Perl data structure for you to manipulate.

fetchall_arrayref( ) operates in three different modes depending on what arguments have been passed to it. It can be called with no arguments, with a reference to an array slice as an argument, and with a reference to a hash slice as an argument. We’ll discuss these modes in the following sections.