SQL::Query::Limit::Oracle - LIMIT emulation for Oracle database.

SQL-Entity documentation Contained in the SQL-Entity distribution.

Index

Code Index:

NAME

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SQL::Query::Limit::Oracle - LIMIT emulation for Oracle database.

SYNOPSIS

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    use SQL::Query::Limit::Oracle;

DESCRIPTION

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    SQL navigation wrapper for Oracle.

EXPORT

None.

ATTRIBUTES

the_rownum

METHODS

query
limit_clause
selectable_columns
the_rownum_column
query_columns

Returns query column for the object.

query_setup
order_by_clause

Returns " ORDER BY ..." SQL fragment

select_hint_clause

Return hinst cluase that will be placed as SELECT operand

SEE ALSO

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SQL::Query.

COPYRIGHT AND LICENSE

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The SQL::Query::Limit::Oracle module is free software. You may distribute under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file.

AUTHOR

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Adrian Witas, adrian@webapp.strefa.pl

SQL-Entity documentation Contained in the SQL-Entity distribution. 
package SQL::Query::Limit::Oracle;

use warnings;
use strict;
use vars qw($VERSION);

$VERSION = '0.01';

use Abstract::Meta::Class ':all';
use SQL::Entity::Column ':all';
use SQL::Entity::Condition ':all';
use base 'SQL::Entity';



has '$.the_rownum';



sub query {
    my ($self, $offset, $limit, $requested_columns, $condition) = @_;
    $condition = $self->limit_clause($offset, $limit, $condition);
    my ($sql, $bind_variables) = $self->SUPER::query($requested_columns, $condition);
    $sql = "SELECT " . $self->alias . ".*"
    . "\nFROM (\n" . $sql . ") " . $self->alias
    . "\nWHERE the_rownum >= ?";
    push @$bind_variables, $offset;
    ($sql, $bind_variables);
}



sub limit_clause {
    my ($self, $offset, $limit, $condition) = @_;
    my $result;
    my $to_rownum = $offset + $limit;  
    if($condition) {
        $result = sql_cond('the_rownum', '<', $to_rownum)->and($condition);
    } else {
        $result = sql_cond('the_rownum', '<', $to_rownum);
    }
    $result;
}

    

sub selectable_columns {
    my ($self, $requested_columns) = @_;
    ($self->the_rownum_column, $self->SUPER::selectable_columns($requested_columns))
}



sub the_rownum_column {
    my ($self) = @_;
    my $the_rownum = $self->the_rownum;
    $the_rownum ||= $self->the_rownum(SQL::Entity::Column->new(name => 'ROWNUM', id => 'the_rownum'));
}



sub query_columns {
    my ($self) = @_;
    (the_rownum =>  $self->the_rownum_column, $self->SUPER::query_columns);
}



sub query_setup {}



sub order_by_clause {
    my ($self) = @_;
    my $index = $self->index or return "";
    return "" if $index->hint;
    " ORDER BY " . $index->order_by_operand($self);
}



sub select_hint_clause {
    my ($self) = @_;
    my $index = $self->index or return "";
    return "" unless $index->hint;
    "/*+ " . $index->hint . " */ ";
}


1;

__END__