wp_get_db_schema( string $scope = 'all', int $blog_id = null ): string

Compatibility

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

Parameters

$scopestringoptional

The tables for which to retrieve SQL. Can be all, global, ms_global, or blog tables. Defaults to all.Default: 'all'

$blog_idintoptional

The site ID for which to retrieve SQL. Default is the current site ID.Default: null

Return value

string

The SQL needed to create the requested tables.

Performance profile

How much work a call to wp_get_db_schema() 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

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

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

Instructions

137–162

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 171.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

2

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

What one call costs · 4 distinct outcomes

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

Uses · 1

• is_multisite()Determines whether Multisite is enabled.

Used by · 2

• dbDelta()Modifies the database based on specified SQL statements.
• install_network()Install Network.

Source code

View on Trac ↗View on GitHub ↗

36<?php37function wp_get_db_schema( $scope = 'all', $blog_id = null ) {38	global $wpdb;39 40	$charset_collate = $wpdb->get_charset_collate();41 42	if ( $blog_id && (int) $blog_id !== $wpdb->blogid ) {43		$old_blog_id = $wpdb->set_blog_id( $blog_id );44	}45 46	// Engage multisite if in the middle of turning it on from network.php.47	$is_multisite = is_multisite() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK );48 49	/*50	 * Indexes have a maximum size of 767 bytes. Historically, we haven't need to be concerned about that.51	 * As of 4.2, however, we moved to utf8mb4, which uses 4 bytes per character. This means that an index which52	 * used to have room for floor(767/3) = 255 characters, now only has room for floor(767/4) = 191 characters.53	 */54	$max_index_length = 191;55 56	// Blog-specific tables.57	$blog_tables = "CREATE TABLE $wpdb->termmeta (58	meta_id bigint(20) unsigned NOT NULL auto_increment,59	term_id bigint(20) unsigned NOT NULL default '0',60	meta_key varchar(255) default NULL,61	meta_value longtext,62	PRIMARY KEY  (meta_id),63	KEY term_id (term_id),64	KEY meta_key (meta_key($max_index_length))65) $charset_collate;66CREATE TABLE $wpdb->terms (67 term_id bigint(20) unsigned NOT NULL auto_increment,68 name varchar(200) NOT NULL default '',69 slug varchar(200) NOT NULL default '',70 term_group bigint(10) NOT NULL default 0,71 PRIMARY KEY  (term_id),72 KEY slug (slug($max_index_length)),73 KEY name (name($max_index_length))74) $charset_collate;75CREATE TABLE $wpdb->term_taxonomy (76 term_taxonomy_id bigint(20) unsigned NOT NULL auto_increment,77 term_id bigint(20) unsigned NOT NULL default 0,78 taxonomy varchar(32) NOT NULL default '',79 description longtext NOT NULL,80 parent bigint(20) unsigned NOT NULL default 0,81 count bigint(20) NOT NULL default 0,82 PRIMARY KEY  (term_taxonomy_id),83 UNIQUE KEY term_id_taxonomy (term_id,taxonomy),84 KEY taxonomy (taxonomy)85) $charset_collate;86CREATE TABLE $wpdb->term_relationships (87 object_id bigint(20) unsigned NOT NULL default 0,88 term_taxonomy_id bigint(20) unsigned NOT NULL default 0,89 term_order int(11) NOT NULL default 0,90 PRIMARY KEY  (object_id,term_taxonomy_id),91 KEY term_taxonomy_id (term_taxonomy_id)92) $charset_collate;93CREATE TABLE $wpdb->commentmeta (94	meta_id bigint(20) unsigned NOT NULL auto_increment,95	comment_id bigint(20) unsigned NOT NULL default '0',96	meta_key varchar(255) default NULL,97	meta_value longtext,98	PRIMARY KEY  (meta_id),99	KEY comment_id (comment_id),100	KEY meta_key (meta_key($max_index_length))101) $charset_collate;102CREATE TABLE $wpdb->comments (103	comment_ID bigint(20) unsigned NOT NULL auto_increment,104	comment_post_ID bigint(20) unsigned NOT NULL default '0',105	comment_author tinytext NOT NULL,106	comment_author_email varchar(100) NOT NULL default '',107	comment_author_url varchar(200) NOT NULL default '',108	comment_author_IP varchar(100) NOT NULL default '',109	comment_date datetime NOT NULL default '0000-00-00 00:00:00',110	comment_date_gmt datetime NOT NULL default '0000-00-00 00:00:00',111	comment_content text NOT NULL,112	comment_karma int(11) NOT NULL default '0',113	comment_approved varchar(20) NOT NULL default '1',114	comment_agent varchar(255) NOT NULL default '',115	comment_type varchar(20) NOT NULL default 'comment',116	comment_parent bigint(20) unsigned NOT NULL default '0',

Changelog

Introduced in 3.3.0. 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 6.7.7 tag, from src/wp-admin/includes/schema.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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