Updating 4 field machine names in Drupal 7

gistfile1.aw

<?php
function er_migration_update_7003() {
  // Changing the names of the porfolio field prefixes from modelp to portfolio
  $fields = array(
    'field_modelp_title' => array(
      'data_col_suffix' => array(
        'value' => 'LONGTEXT',
        'format' => 'VARCHAR(255) DEFAULT NULL',
      ),
    ),
    'field_modelp_desc' => array(
      'data_col_suffix' => array(
        'value' => 'LONGTEXT',
        'format' => 'VARCHAR(255) DEFAULT NULL',
      ),
    ),
    'field_modelp_type' => array(
      'data_col_suffix' => array(
        'value' => 'LONGTEXT',
        'format' => 'VARCHAR(255) DEFAULT NULL',
      ),
    ),
    'field_modelp_link' => array(
      'data_col_suffix' => array(
        'url' => "VARCHAR(2048) DEFAULT NULL",
        'title' => "VARCHAR(255) DEFAULT NULL",
        'attributes' => 'MEDIUMTEXT',
      ),
    ),
  );
  $replace = array(
    'modelp' => 'portfolio',
  );
  
  foreach ($fields as $old_field_name => $field) {
    $new_field_name = str_replace(array_keys($replace), $replace, $old_field_name);
    $args[':new_field_name'] = $new_field_name;
    $args[':field_name'] = $old_field_name;
    $q[] = array(
      'query' => "UPDATE {field_config} SET field_name = :new_field_name WHERE field_name = :field_name",
      'args' => $args,
    );
    $q[] = array(
      'query' => "UPDATE {field_config_instance} SET field_name = :new_field_name WHERE field_name = :field_name",
      'args' => $args,
    );
    
    
    foreach (array('revision', 'data') as $type) {
      $old_table = "field_". $type ."_". $old_field_name;
      $new_table = "field_". $type ."_". $new_field_name;
      $q[] = array(
        'query' => "RENAME TABLE `". $old_table ."` TO `". $new_table ."`",
      );
      
      foreach ($field['data_col_suffix'] as $suffix => $extra) {
        $old_col = $old_field_name .'_'. $suffix;
        $new_col = $new_field_name .'_'. $suffix;
        $q[] = array(
          'query' => 'ALTER TABLE `'. $new_table .'` CHANGE `'. $old_col .'` `'. $new_col .'` '. $extra,
        );
      }
    }
  }
  
  foreach ($q as $i) {
    $args = (empty($i['args'])) ? array() : $i['args'];
    db_query($i['query'], $args);
  }
}