farmOS/modules/farm/farm_sensor/farm_sensor_listener/farm_sensor_listener.install

<?php

/**
 * @file
 * Farm sensor listener install.
 */

/**
 * Implements hook_schema().
 */
function farm_sensor_listener_schema() {
  $schema['farm_sensor_data'] = array(
    'description' => 'Farm sensor data storage',
    'fields' => array(
      'id' => array(
        'description' => 'Farm sensor asset ID',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ),
      'timestamp' => array(
        'description' => 'Timestamp of the sensor reading',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'name' => array(
        'description' => 'Sensor reading name',
        'type' => 'varchar',
        'length' => '255',
        'not null' => FALSE,
      ),
      'value_numerator' => array(
        'description' => 'Value numerator',
        'type' => 'int',
        'size' => 'big',
        'not null' => TRUE,
        'default' => 0,
      ),
      'value_denominator' => array(
        'description' => 'Value denominator',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 1,
      ),
    ),
    'indexes' => array(
      'id' => array('id'),
      'name' => array('name'),
      'timestamp' => array('timestamp'),
    ),
  );
  return $schema;
}

/**
 * Do not allow null timestamp values in sensor data table.
 */
function farm_sensor_listener_update_7000(&$sandbox) {

  // Drop the index.
  db_drop_index('farm_sensor_data', 'timestamp');

  // Set all NULL values to 0.
  db_query('UPDATE {farm_sensor_data} SET timestamp = 0 WHERE timestamp IS NULL');

  // Change the field.
  $timestamp = array(
    'description' => 'Timestamp of the sensor reading',
    'type' => 'int',
    'not null' => TRUE,
    'default' => 0,
  );
  $timestamp_keys = array(
    'indexes' => array(
      'timestamp' => array('timestamp'),
    ),
  );
  db_change_field('farm_sensor_data', 'timestamp', 'timestamp', $timestamp, $timestamp_keys);
}