update_option( string $option, mixed $value, string|bool $autoload = null )

更新已添加的选项的值。
Updates the value of an option that was already added.

目录锚点：#说明#参数#源码#笔记

说明（Description）

不需要序列化值。如果需要序列化该值，则在将其插入数据库之前将其序列化。请记住，资源不能序列化或作为选项添加。如果选项不存在，则将创建该选项。此功能设计为在有或无登录用户的情况下工作。在安全性方面，插件开发人员应该在更新任何选项之前检查当前用户的能力。

参数（Parameters）

源码（Source）

/**
 * Update the value of an option that was already added.
 *
 * You do not need to serialize values. If the value needs to be serialized, then
 * it will be serialized before it is inserted into the database. Remember,
 * resources can not be serialized or added as an option.
 *
 * If the option does not exist, then the option will be added with the option value,
 * with an `$autoload` value of 'yes'.
 *
 * @since 1.0.0
 * @since 4.2.0 The `$autoload` parameter was added.
 *
 * @global wpdb $wpdb
 *
 * @param string      $option   Option name. Expected to not be SQL-escaped.
 * @param mixed       $value    Option value. Must be serializable if non-scalar. Expected to not be SQL-escaped.
 * @param string|bool $autoload Optional. Whether to load the option when WordPress starts up. For existing options,
 *                              `$autoload` can only be updated using `update_option()` if `$value` is also changed.
 *                              Accepts 'yes'|true to enable or 'no'|false to disable. For non-existent options,
 *                              the default value is 'yes'. Default null.
 * @return bool False if value was not updated and true if value was updated.
 */
function update_option( $option, $value, $autoload = null ) {
	global $wpdb;

	$option = trim($option);
	if ( empty($option) )
		return false;

	wp_protect_special_option( $option );

	if ( is_object( $value ) )
		$value = clone $value;

	$value = sanitize_option( $option, $value );
	$old_value = get_option( $option );

	/**
	 * Filter a specific option before its value is (maybe) serialized and updated.
	 *
	 * The dynamic portion of the hook name, `$option`, refers to the option name.
	 *
	 * @since 2.6.0
	 *
	 * @param mixed $value     The new, unserialized option value.
	 * @param mixed $old_value The old option value.
	 */
	$value = apply_filters( 'pre_update_option_' . $option, $value, $old_value );

	/**
	 * Filter an option before its value is (maybe) serialized and updated.
	 *
	 * @since 3.9.0
	 *
	 * @param mixed  $value     The new, unserialized option value.
	 * @param string $option    Name of the option.
	 * @param mixed  $old_value The old option value.
	 */
	$value = apply_filters( 'pre_update_option', $value, $option, $old_value );

	// If the new and old values are the same, no need to update.
	if ( $value === $old_value )
		return false;

	/** This filter is documented in wp-includes/option.php */
	if ( apply_filters( 'default_option_' . $option, false ) === $old_value ) {
		// Default setting for new options is 'yes'.
		if ( null === $autoload ) {
			$autoload = 'yes';
		}

		return add_option( $option, $value, '', $autoload );
	}

	$serialized_value = maybe_serialize( $value );

	/**
	 * Fires immediately before an option value is updated.
	 *
	 * @since 2.9.0
	 *
	 * @param string $option    Name of the option to update.
	 * @param mixed  $old_value The old option value.
	 * @param mixed  $value     The new option value.
	 */
	do_action( 'update_option', $option, $old_value, $value );

	$update_args = array(
		'option_value' => $serialized_value,
	);

	if ( null !== $autoload ) {
		$update_args['autoload'] = ( 'no' === $autoload || false === $autoload ) ? 'no' : 'yes';
	}

	$result = $wpdb->update( $wpdb->options, $update_args, array( 'option_name' => $option ) );
	if ( ! $result )
		return false;

	$notoptions = wp_cache_get( 'notoptions', 'options' );
	if ( is_array( $notoptions ) && isset( $notoptions[$option] ) ) {
		unset( $notoptions[$option] );
		wp_cache_set( 'notoptions', $notoptions, 'options' );
	}

	if ( ! defined( 'WP_INSTALLING' ) ) {
		$alloptions = wp_load_alloptions();
		if ( isset( $alloptions[$option] ) ) {
			$alloptions[ $option ] = $serialized_value;
			wp_cache_set( 'alloptions', $alloptions, 'options' );
		} else {
			wp_cache_set( $option, $serialized_value, 'options' );
		}
	}

	/**
	 * Fires after the value of a specific option has been successfully updated.
	 *
	 * The dynamic portion of the hook name, `$option`, refers to the option name.
	 *
	 * @since 2.0.1
	 *
	 * @param mixed $old_value The old option value.
	 * @param mixed $value     The new option value.
	 */
	do_action( "update_option_{$option}", $old_value, $value );

	/**
	 * Fires after the value of an option has been successfully updated.
	 *
	 * @since 2.9.0
	 *
	 * @param string $option    Name of the updated option.
	 * @param mixed  $old_value The old option value.
	 * @param mixed  $value     The new option value.
	 */
	do_action( 'updated_option', $option, $old_value, $value );
	return true;
}

笔记（Notes）

根据WordPress Codex（以及我使用WP开发的经验），请注意这里返回值中的一个重要细节：