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lib/DBIx/Connection/PostgreSQL/SQL.pm  view on Meta::CPAN

    my ($class, $sequence_name) = @_;
    "SELECT nextval('${sequence_name}') AS val"
}


=item reset_sequence

Returns sql statement that restarts sequence.

=cut

sub reset_sequence {
    my ($class, $sequence_name, $restart_with, $increment_by) = @_;
    ("ALTER SEQUENCE ${sequence_name} RESTART WITH ${restart_with}",
     ($increment_by ? "ALTER SEQUENCE ${sequence_name} INCREMENT  ${increment_by}" : ()));
}


=item has_sequence

Returns sql statement that check is sequence exists in database schema

=cut

sub has_sequence {
    my ($class, $schema) = @_;
    "SELECT pc.relname AS sequence_name
    FROM pg_class pc 
    JOIN pg_authid pa ON pa.oid = pc.relowner AND pc.relkind = 'S' AND  pc.relname = lower(?)  AND rolname = '". $schema ."' ";
}


=item set_session_variables

Sets session variables

It uses the following sql command pattern:

    SET variable TO value;

    DBIx::Connection::PostgreSQL::SQL->set_session_variables($connection, {DateStyle => 'US'});

=cut

sub set_session_variables {
    my ($class, $connection, $db_session_variables) = @_;
    my $sql = "";
    $sql .= "SET " . $_ . " TO " . $db_session_variables->{$_} . ";"
      for keys %$db_session_variables;
    $connection->do($sql);
}


=item update_lob

Updates lob. (Large Object)
Takes connection object, table name, lob column_name, lob conetent, hash_ref to primary key values. optionally lob size column name.

=cut

sub update_lob {
    my ($class, $connection, $table_name, $lob_column_name, $lob, $primary_key_values, $lob_size_column_name) = @_;
    confess "missing primary key for lob update on ${table_name}.${lob_column_name}"
        if (!$primary_key_values  || ! (%$primary_key_values));
    confess "missing lob size column name" unless $lob_size_column_name;
    my $sql = "UPDATE ${table_name} SET ${lob_column_name} = ? ";
    $sql .= ($lob_size_column_name ? ", ${lob_size_column_name} = ? " : '')
      . $connection->_where_clause($primary_key_values);
    
    $class->_unlink_lob($connection, $class->_get_lob_id($connection, $table_name, $primary_key_values, $lob_column_name));
    my $lob_id = $class->_create_lob($connection, $lob);
    my $bind_counter = 1;
    my $sth = $connection->dbh->prepare($sql);
    $sth->bind_param($bind_counter++ ,$lob_id);
    $sth->bind_param($bind_counter++ , length($lob)) if $lob_size_column_name;
    for my $k (sort keys %$primary_key_values) {
        $sth->bind_param($bind_counter++ , $primary_key_values->{$k});
    }
    $sth->execute();
}



=item fetch_lob

Retrieve lobs.
Takes connection object, table name, lob column_name, hash_ref to primary key values. optionally lob size column name.
By default max lob size is set to 1 GB
DBIx::Connection::Oracle::SQL::LOB_MAX_SIZE = (1024 * 1024 * 1024);

=cut

sub fetch_lob {
    my ($class, $connection, $table_name, $lob_column_name, $primary_key_values, $lob_size_column_name) = @_;
    confess "missing primary key for lob update on ${table_name}.${lob_column_name}"
        if (! $primary_key_values  || ! (%$primary_key_values));
    confess "missing lob size column name" unless $lob_size_column_name;
    my $lob_id = $class->_get_lob_id($connection, $table_name, $primary_key_values, $lob_column_name);
    my $lob_size = $class->_get_lob_size($connection, $table_name, $primary_key_values, $lob_size_column_name);
    $class->_read_lob($connection, $lob_id, $lob_size);
}



=item _create_lob

Creates lob

=cut

sub _create_lob {
    my ($class, $connection, $lob) = @_;
    my $dbh = $connection->dbh;
    my $autocomit_mode = $connection->has_autocomit_mode;
    $connection->begin_work if $autocomit_mode;
    my $mode = $dbh->{pg_INV_WRITE};
    my $lob_id = $dbh->func($mode, 'lo_creat')
        or confess "can't create lob ". $!;
    my $lobj_fd = $dbh->func($lob_id, $mode, 'lo_open');
    confess "can't open lob ${lob_id}". $!
        unless defined $lobj_fd;