Question

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

Update post meta field based on post ID.

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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.

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参数

$post_id

(int) (Required) Post ID.

$meta_key

(string) (Required) Metadata key.

$meta_value

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

$prev_value

(mixed) (Optional) Previous value to check before removing.

Default value: ''

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返回值

(int|bool) Meta ID if the key didn't exist, true on successful update, false on failure.

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源代码

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;

	return update_metadata('post', $post_id, $meta_key, $meta_value, $prev_value);
}

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更新日志

Version	description
1.5.0	Introduced.

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相关函数

Uses

• wp-includes/revision.php: wp_is_post_revision()
• wp-includes/meta.php: update_metadata()

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Used By

• wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::import_theme_starter_content()
• wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php: WP_REST_Attachments_Controller::create_item()
• wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php: WP_REST_Attachments_Controller::update_item()
• wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php: WP_REST_Posts_Controller::handle_template()
• wp-admin/custom-background.php: Custom_Background::ajax_background_add()
• wp-admin/includes/image-edit.php: wp_restore_image()
• wp-admin/includes/image-edit.php: wp_save_image()
• wp-admin/includes/image.php: wp_generate_attachment_metadata()
• wp-admin/includes/media.php: media_upload_form_handler()
• wp-admin/includes/post.php: wp_set_post_lock()
• wp-admin/includes/post.php: edit_post()
• wp-admin/includes/ajax-actions.php: wp_ajax_upload_attachment()
• wp-admin/includes/ajax-actions.php: wp_ajax_wp_remove_post_lock()
• wp-admin/includes/ajax-actions.php: wp_ajax_save_attachment()
• wp-admin/custom-header.php: Custom_Image_Header::ajax_header_add()
• wp-admin/custom-header.php: Custom_Image_Header::customize_set_last_used()
• wp-admin/custom-header.php: Custom_Image_Header::set_header_image()
• wp-admin/custom-background.php: Custom_Background::wp_set_background_image()
• wp-admin/custom-background.php: Custom_Background::handle_upload()
• wp-includes/class-wp-embed.php: WP_Embed::shortcode()
• wp-includes/post.php: set_post_thumbnail()
• wp-includes/post.php: wp_update_attachment_metadata()
• wp-includes/post.php: wp_insert_post()
• wp-includes/post.php: update_attached_file()
• wp-includes/revision.php: wp_restore_post_revision()
• wp-includes/nav-menu.php: wp_update_nav_menu_item()
Show 21 more used by Hide more used by

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User Contributed Notes

1. Skip to note content You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note Contributed by Fiaz Husyn

   Note: if there are multiple values for a single key, all the values will get updated if $prev_value is not set.

Default Usage

<?php update_post_meta( $post_id = 76, $key = 'my_key', $value = 'Steve' ); ?>

Other Examples
Assuming a post has an ID of 76, and the following 4 custom fields:

[key_1] => 'Happy'
[key_1] => 'Sad'
[key_2] => 'Gregory'
[my_key] => 'Steve'

To change key_2’s value to Hans:

<?php update_post_meta( 76, 'key_2', 'Hans' ); ?>

To change key_1’s value from Sad to Happy:

<?php update_post_meta( 76, 'key_1', 'Happy', 'Sad' ); ?>

The fields would now look like this:

[key_1] => 'Happy'
[key_1] => 'Happy'
[key_2] => 'Hans'
[my_key] => 'Steve'

Note: This function will update only the first field that matches the criteria.

To change the first key_1’s value from Happy to Excoded:

<?php 
update_post_meta( 76, 'key_1', 'Excoded', 'Happy' );

//Or

update_post_meta( 76, 'key_1', 'Excoded' );

//To change all fields with the key "key_1":

$key1_values = get_post_custom_values( 'key_1', 76 );
foreach ( $key1_values as $value )
	update_post_meta( 76, 'key_1', 'Excoded', $value );
?>

Edit Page template

[/php]

For a more detailed example, go to the post_meta Functions Examples page.