delete_metadata( string $meta_type, int $object_id, string $meta_key, mixed $meta_value = '', bool $delete_all = false ): bool

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$meta_typestring

Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.

$object_idint

ID of the object metadata is for.

$meta_keystring

Metadata key.

$meta_valuemixedoptional

Metadata value. Must be serializable if non-scalar.
If specified, only delete metadata entries with this value.
Otherwise, delete all entries with the specified meta_key.
Pass null, false, or an empty string to skip this check.
(For backward compatibility, it is not possible to pass an empty string to delete those entries with an empty string for a value.) Default empty string.Default: ''

$delete_allbooloptional

If true, delete matching metadata entries for all objects, ignoring the specified object_id. Otherwise, only delete matching metadata entries for the specified object_id. Default false.Default: false

Return value

bool

True on successful delete, false on failure.

Performance profile

How much work a call to delete_metadata() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via ->get_col().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

8–172

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 194.

Plugin surface

5 hooks

Third-party callbacks on 'delete_{$meta_type}_metadata', 'delete_{$meta_type}_meta', 'delete_postmeta' run inside this call, and their cost is not bounded by anything here.

Called by

14

14 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly
• serializeserialisationmaybe_serialize()called directly
• cacheobject cachewp_cache_delete_multiple()called directly
• sqldatabase query->get_col()called directly

What one call costs · 43 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost delete_metadata() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 5

5 hooks fire while delete_metadata() runs, in this order:

1. 1
   apply_filters( delete_{$meta_type}_metadata )filterline 434 (+48 into the body)

   Short-circuits deleting metadata of a specific type.

2. 2
   do_action( delete_{$meta_type}_meta )actionline 485 (+99 into the body)

   Fires immediately before deleting metadata of a specific type.

3. 3
   do_action( delete_postmeta )actionline 496 (+110 into the body)

   Fires immediately before deleting metadata for a post.

4. 4
   do_action( deleted_{$meta_type}_meta )actionline 534 (+148 into the body)

   Fires immediately after deleting metadata of a specific type.

5. 5
   do_action( deleted_postmeta )actionline 545 (+159 into the body)

   Fires immediately after deleting metadata for a post.

Uses · 8

• absint()Converts a value to non-negative integer.
• _get_meta_table()Retrieves the name of the metadata table for the specified object type.
• sanitize_key()Sanitizes a string key.
• wp_unslash()Removes slashes from a string or recursively removes slashes from strings within an array.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• maybe_serialize()Serializes data, if needed.
• do_action()Calls the callback functions that have been added to an action hook.
• wp_cache_delete_multiple()Deletes multiple values from the cache in one call.

Used by · 14

• WP_REST_Meta_Fields::delete_meta_value()Deletes a meta value for an object.
• WP_REST_Meta_Fields::update_multi_meta_value()Updates multiple meta values for an object.
• WP_User_Meta_Session_Tokens::drop_sessions()Destroys all sessions for all users.
• delete_comment_meta()Removes metadata matching criteria from a comment.
• delete_post_meta()Deletes a post meta field for the given post ID.
• delete_post_meta_by_key()Deletes everything from post meta matching the given meta key.
• delete_site_meta()Removes metadata matching criteria from a site.
• delete_site_meta_by_key()Deletes everything from site meta matching meta key.
• delete_term_meta()Removes metadata matching criteria from a term.
• delete_user_meta()Removes metadata matching criteria from a user.
• install_blog()Install an empty blog.
• wp_autosave_post_revisioned_meta_fields()Autosaves the revisioned meta fields.

Source code

View on Trac ↗View on GitHub ↗

386function delete_metadata( $meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false ) {387	global $wpdb;388 389	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) && ! $delete_all ) {390		return false;391	}392 393	$object_id = absint( $object_id );394	if ( ! $object_id && ! $delete_all ) {395		return false;396	}397 398	$table = _get_meta_table( $meta_type );399	if ( ! $table ) {400		return false;401	}402 403	$type_column = sanitize_key( $meta_type . '_id' );404	$id_column   = ( 'user' === $meta_type ) ? 'umeta_id' : 'meta_id';405 406	// expected_slashed ($meta_key)407	$meta_key   = wp_unslash( $meta_key );408	$meta_value = wp_unslash( $meta_value );409 410	/**411	 * Short-circuits deleting metadata of a specific type.412	 *413	 * The dynamic portion of the hook name, `$meta_type`, refers to the meta object type414	 * (post, comment, term, user, or any other type with an associated meta table).415	 * Returning a non-null value will effectively short-circuit the function.416	 *417	 * Possible hook names include:418	 *419	 *  - `delete_post_metadata`420	 *  - `delete_comment_metadata`421	 *  - `delete_term_metadata`422	 *  - `delete_user_metadata`423	 *424	 * @since 3.1.0425	 *426	 * @param null|bool $delete     Whether to allow metadata deletion of the given type.427	 * @param int       $object_id  ID of the object metadata is for.428	 * @param string    $meta_key   Metadata key.429	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.430	 * @param bool      $delete_all Whether to delete the matching metadata entries431	 *                              for all objects, ignoring the specified $object_id.432	 *                              Default false.433	 */434	$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );435	if ( null !== $check ) {436		return (bool) $check;437	}438 439	$_meta_value = $meta_value;440	$meta_value  = maybe_serialize( $meta_value );441 442	$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );443 444	if ( ! $delete_all ) {445		$query .= $wpdb->prepare( " AND $type_column = %d", $object_id );446	}447 448	if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value ) {449		$query .= $wpdb->prepare( ' AND meta_value = %s', $meta_value );450	}451 452	$meta_ids = $wpdb->get_col( $query );453	if ( ! count( $meta_ids ) ) {454		return false;455	}456 457	if ( $delete_all ) {458		if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value ) {459			$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s AND meta_value = %s", $meta_key, $meta_value ) );460		} else {461			$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s", $meta_key ) );462		}463	}464 465	/**

Changelog

Introduced in 2.9.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.8.8 tag, from src/wp-includes/meta.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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