update_post_meta( int $post_id, string $meta_key, mixed $meta_value, mixed $prev_value = '' )

Updates a post meta field based on the given post ID.

Description

Use the $prev_value parameter to differentiate between meta fields with the same key and post ID.

If the meta field for the post does not exist, it will be added and its ID returned.

Can be used in place of add_post_meta().

Parameters

$post_id

(Required) Post ID.

$meta_key

(Required) Metadata key.

$meta_value

(Required) Metadata value. Must be serializable if non-scalar.

$prev_value

(Optional) Previous value to check before updating.<br> If specified, only update existing metadata entries with this value. Otherwise, update all entries.

Default value: ''

Return

(int|bool) Meta ID if the key didn't exist, true on successful update, false on failure or if the value passed to the function is the same as the one that is already in the database.

Source

File: wp-includes/post.php 

function update_post_meta( $post_id, $meta_key, $meta_value, $prev_value = '' ) {
	// Make sure meta is added to the post, not a revision.
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	$updated = update_metadata( 'post', $post_id, $meta_key, $meta_value, $prev_value );
	if ( $updated ) {
		wp_cache_set( 'last_changed', microtime(), 'posts' );
	}
	return $updated;
}

Expand Source Code View on GitHub

Related

Uses

Uses
Uses Description
wp-includes/meta.php: update_metadata()

Updates metadata for the specified object. If no value already exists for the specified object ID and metadata key, the metadata will be added.
wp-includes/revision.php: wp_is_post_revision()

Determines if the specified post is a revision.

Used By

Used By
Used By Description
wp-admin/includes/media.php: bulk_edit_attachments()

Processes the post data for the bulk editing of attachments.
wp-admin/includes/ajax-actions.php: wp_ajax_quick_edit_attachment()

Ajax handler for updating attachment values and attributes.
wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php: WP_REST_Attachments_Controller::edit_media_item()

Applies edits to a media item and creates a new attachment record.
wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php: WP_REST_Attachments_Controller::create_item()

Creates a single attachment.
wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php: WP_REST_Attachments_Controller::update_item()

Updates a single attachment.
wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php: WP_REST_Posts_Controller::handle_template()

Sets the template for a post.
wp-includes/nav-menu.php: wp_update_nav_menu_item()

Saves the properties of a menu item or create a new one.
wp-includes/class-wp-embed.php: WP_Embed::shortcode()

The do_shortcode() callback function.
wp-includes/user.php: _wp_privacy_account_request_confirmed()

Updates log when privacy request is confirmed.
wp-includes/user.php: _wp_privacy_send_request_confirmation_notification()

Notifies the site administrator via email when a request is confirmed.
wp-includes/user.php: _wp_privacy_send_erasure_fulfillment_notification()

Notifies the user when their erasure request is fulfilled.
wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::dismiss_user_auto_draft_changesets()

Dismisses all of the current user’s auto-drafts (other than the present one).
wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::import_theme_starter_content()

Imports theme starter content into the customized state.
wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::set_changeset_lock()

Marks the changeset post as being currently edited by the current user.
wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::refresh_changeset_lock()

Refreshes changeset lock with the current time if current user edited the changeset before.
wp-includes/post.php: set_post_thumbnail()

Sets the post thumbnail (featured image) for the given post.
wp-includes/post.php: wp_update_attachment_metadata()

Updates metadata for an attachment.
wp-includes/post.php: wp_insert_post()

Inserts or update a post.
wp-includes/post.php: update_attached_file()

Updates attachment file path based on attachment ID.
wp-includes/revision.php: wp_restore_post_revision()

Restores a post to the specified revision.
wp-admin/includes/class-custom-background.php: Custom_Background::handle_upload()

Handles an Image upload for the background image.
wp-admin/includes/class-custom-background.php: Custom_Background::ajax_background_add()

Handles Ajax request for adding custom background context to an attachment.
wp-admin/includes/class-custom-background.php: Custom_Background::wp_set_background_image()
wp-admin/includes/class-custom-image-header.php: Custom_Image_Header::set_header_image()

Choose a header image, selected from existing uploaded and default headers, or provide an array of uploaded header data (either new, or from media library).
wp-admin/includes/class-custom-image-header.php: Custom_Image_Header::ajax_header_add()

Given an attachment ID for a header image, updates its “last used” timestamp to now.
wp-admin/includes/class-custom-image-header.php: Custom_Image_Header::customize_set_last_used()

Updates the last-used postmeta on a header image attachment after saving a new header image via the Customizer.
wp-admin/includes/image.php: wp_generate_attachment_metadata()

Generates attachment meta data and create image sub-sizes for images.
wp-admin/includes/media.php: media_upload_form_handler()

Handles form submissions for the legacy media uploader.
wp-admin/includes/image-edit.php: wp_save_image()

Saves image to post, along with enqueued changes in $_REQUEST['history'].
wp-admin/includes/image-edit.php: wp_restore_image()

Restores the metadata for a given attachment.
wp-admin/includes/ajax-actions.php: wp_ajax_wp_remove_post_lock()

Ajax handler for removing a post lock.
wp-admin/includes/ajax-actions.php: wp_ajax_save_attachment()

Ajax handler for updating attachment attributes.
wp-admin/includes/ajax-actions.php: wp_ajax_upload_attachment()

Ajax handler for uploading attachments
wp-admin/includes/privacy-tools.php: _wp_privacy_completed_request()

Marks a request as completed by the admin and logs the current timestamp.
wp-admin/includes/privacy-tools.php: wp_privacy_generate_personal_data_export_file()

Generate the personal data export file.
wp-admin/includes/privacy-tools.php: wp_privacy_process_personal_data_export_page()

Intercept personal data exporter page Ajax responses in order to assemble the personal data export file.
wp-admin/includes/post.php: wp_set_post_lock()

Marks the post as currently being edited by the current user.
wp-admin/includes/post.php: edit_post()

Updates an existing post with values provided in $_POST.
wp-admin/includes/post.php: bulk_edit_posts()

Processes the post data for the bulk editing of posts.
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Changelog

Changelog
Version Description
1.5.0 Introduced.