Gryphon Shafer > SQL-Abstract-Complete > SQL::Abstract::Complete

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Module Version: 1.04   Source  

NAME ^

SQL::Abstract::Complete - Generate complete SQL from Perl data structures

SYNOPSIS ^

    use SQL::Abstract::Complete;

    my $sac = SQL::Abstract::Complete->new();

    my ( $sql, @bind ) = $sac->select(
        \@tables, # a table or set of tables and optional aliases
        \@fields, # fields and optional aliases to fetch
        \%where,  # where clause
        \%other,  # order by, group by, having, and pagination
    );

DESCRIPTION ^

This module was inspired by the excellent SQL::Abstract, from which in inherits. However, in trying to use the module, I found that what I really wanted to do was generate complete SELECT statements including joins and group by clauses. So, I set out to create a more complete abstract SQL generation module. (To be fair, SQL::Abstract kept it's first $table argument inflexible for backwards compatibility reasons.)

This module only changes the select() method and adds a small new wrinkle to new(). Everything else from SQL::Abstract is inheritted as-is. Consequently, you should read the SQL::Abstract documentation before continuing.

FUNCTIONS ^

new( 'option' => 'value' )

The new() function takes a list of options and values, and returns a new SQL::Abstract::Complete object which can then be used to generate SQL. This function operates in exactly the same way as the same from SQL::Abstract only it offers one additional option to set:

part_join

This is the value that the SELECT statement components will be concatinated together with. By default, this is set to a single space, meaning the returned SQL will be all on one line. Setting this to something like "\n" would make for slightly more human-readable SQL, depending on the human.

select( \@tables, \@fields, \%where, \%other )

This returns a SQL SELECT statement and associated list of bind values, as specified by the arguments:

\@tables

This is a list of tables, optional aliases, and ways to join any multiple tables. The first table will be used as the "FROM" part of the statement. Subsequent tables will be assumed to be joined by use of an inner join unless otherwise specified.

There are several ways to specify tables, joins, and their respective aliases:

    # SELECT * FROM alpha
    my ( $sql, @bind ) = $sac->select('alpha');
    my ( $sql, @bind ) = $sac->select( ['alpha'] );

    # SELECT * FROM alpha AS a
    ( $sql, @bind ) = $sac->select( \q(FROM alpha AS a) );
    ( $sql, @bind ) = $sac->select( [ \q(FROM alpha AS a) ] );

    # SELECT * FROM alpha AS a JOIN beta AS b USING(id)
    $sac->select(
        [
            [ [ qw( alpha a ) ]       ],
            [ [ qw( beta  b ) ], 'id' ],
        ],
    );
    $sac->select(
        [
            [ [ qw( alpha a ) ] ],
            [ { 'beta' => 'b' }, 'id' ],
        ],
    );

    # SELECT *
    # FROM alpha AS a
    # JOIN beta AS b USING(id)
    # LEFT JOIN something AS s USING(whatever)
    # LEFT JOIN omega AS o USING(last_id)
    # LEFT JOIN stuff AS t ON t.thing_id = b.thing_id
    # LEFT JOIN pi AS p USING(number_id)
    $sac->select(
        [
            [ [ qw( alpha a ) ] ],
            [ { 'beta' => 'b' }, 'id' ],
            \q{ LEFT JOIN something AS s USING(whatever) },
            [ \q{ LEFT JOIN }, { 'omega', 'o' }, 'last_id' ],
            [
                \q{ LEFT JOIN },
                { 'stuff' => 't' },
                \q{ ON t.thing_id = b.thing_id },
            ],
            [
                [ qw( pi p ) ],
                {
                    'join'  => 'left',
                    'using' => 'number_id',
                },
            ],
        ],
    );
\@fields

This is a list of the fields (along with optional aliases) to return. There are several ways to specify fields and their respective aliases:

    # SELECT one, two, three FROM table
    $sac->select(
        'table',
        [ qw( one two three ) ],
    );

    # SELECT one, IF( two > 10, 1, 0 ) AS two_bool, three AS col_three
    # FROM table
    $sac->select(
        'table',
        [
            'one',
            \q{ IF( two > 10, 1, 0 ) AS two_bool },
            { 'three' => 'col_three' },
        ],
    );
\%where

This is an optional argument to specify the WHERE clause of the query. The argument is most often a hashref. This functionality is entirely inheritted from SQL::Abstract, so read that fine module's documentation for WHERE details.

\%other

This optional argument is where you can specify items like order by, group by, and having clauses. You can also stipulate pagination of results.

    # SELECT one
    # FROM table
    # GROUP BY two
    # HAVING ( MAX(three) > ? )
    # ORDER BY one, four DESC, five
    # LIMIT 10, 5
    $sac->select(
        'table',
        ['one'],
        undef,
        {
            'group_by' => 'two',
            'having'   => [ { 'MAX(three)' => { '>' => 9 } } ],
            'order_by' => [ 'one', { '-desc' => 'four' }, 'five' ],
            'rows'     => 5,
            'page'     => 3,
        },
    );

The HAVING clause works in the same way as the WHERE clause handling from SQL::Abstract. (In fact, we're actually calling the same method from the parent class.) ORDER BY clause handling is also purely inheritted from SQL::Abstract. The "rows" and "page" pagination functionality is inspired from DBIx::Class and operates the same way. Alternatively, you can explicitly set a "limit" value.

SEE ALSO ^

SQL::Abstract, DBIx::Class, DBIx::Abstract.

AUTHOR ^

Gryphon Shafer <gryphon@cpan.org>.

  code('Perl') || die;

LICENSE ^

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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