DBIx::Simple::SQE - Add subquery emulation to DBIx::Simple

NAME

DBIx::Simple::SQE - Add subquery emulation to DBIx::Simple

SYNOPSIS

    my $db = DBIx::Simple::SQE->connect(...);

    my $result = $db->query(
        q[
            SELECT project_name
            FROM   projects
            WHERE  user_id IN (
                SELECT id
                FROM   users
                WHERE  email = ?
            )
            AND    status = ?
        ],
        $email, $status
    );

Is simply a more compact way of doing:

    my $db = DBIx::Simple::SQE->connect(...);

    my $result = $db->query(
        sprintf(
            q[
                SELECT project_name
                FROM   projects
                WHERE  user_id IN (%s)
                AND    status = ?
            ],
            join(
                ',',
                map(
                    $db->dbh->quote($_),
                    $db->query(
                        q[
                            SELECT id
                            FROM   users
                            WHERE  email = ?
                        ],
                        $email
                    )->flat
                )
            )
        ),
        $status
    );

DESCRIPTION

This module is not actively maintained. In practice that means that if you find a bug, you'll have to fix it yourself or live with it. (Patches are welcome, though). If DBIx::Simple changes in a way that is incompatible with this module, SQE will simply stop functioning correctly. Should you want to take over maintenance of this module, let me know.

This module extends DBIx::Simple by making query emulate nested subqueries (SELECT only) by executing them and interpolating the results.

This module should not be used if the database provides real subqueries. It is better to use a database engine that has real subqueries than to use this module.

Only subqueries like (SELECT ...) (note the parentheses) are interpolated.

Please note that emulation is done by doing multiple queries and is not atomic, as it would be if the database supported real subqueries. The queries are executed independently.

HISTORY

Subquery emulation used to be built into DBIx::Simple itself. It was enabled by using the emulate_subqueries property (or its alias esq).

Starting from version 1.20, the feature was deprecated. In version 1.23, it was finally removed. To give users some more time, it was moved to a separate module.

LICENSE

There is no license. This software was released into the public domain. Do with it what you want, but on your own risk. The author disclaims any responsibility.

AUTHOR