is_blog_installed() │ WP 2.1.0

Test whether WordPress is already installed.

The cache will be checked first. If you have a cache plugin, which saves the cache values, then this will work. If you use the default WordPress cache, and the database goes away, then you might have problems.

Checks for the 'siteurl' option for whether WordPress is installed.

For more information on this and similar theme functions, check out the Conditional Tags article in the Theme Developer Handbook.

1 time — 0.000026 sec (very fast) | 50000 times — 0.07 sec (speed of light) | PHP 7.0.14, WP 4.7

No Hooks.

Return

true|false. Whether the site is already installed.

Usage

is_blog_installed();

Examples

0

#1 Check if the site is installed, before registering the widget 

function widgets_init() {

	if ( ! is_blog_installed() ) {
		return;
	}

	register_widget( 'WP_Widget_Black_Studio_TinyMCE' );
}

Notes

  • Global. wpdb. $wpdb WordPress database abstraction object.

Changelog

Since 2.1.0 Introduced.

is_blog_installed() code WP 6.7.1

wp-includes/functions.php 
function is_blog_installed() {
	global $wpdb;

	/*
	 * Check cache first. If options table goes away and we have true
	 * cached, oh well.
	 */
	if ( wp_cache_get( 'is_blog_installed' ) ) {
		return true;
	}

	$suppress = $wpdb->suppress_errors();

	if ( ! wp_installing() ) {
		$alloptions = wp_load_alloptions();
	}

	// If siteurl is not set to autoload, check it specifically.
	if ( ! isset( $alloptions['siteurl'] ) ) {
		$installed = $wpdb->get_var( "SELECT option_value FROM $wpdb->options WHERE option_name = 'siteurl'" );
	} else {
		$installed = $alloptions['siteurl'];
	}

	$wpdb->suppress_errors( $suppress );

	$installed = ! empty( $installed );
	wp_cache_set( 'is_blog_installed', $installed );

	if ( $installed ) {
		return true;
	}

	// If visiting repair.php, return true and let it take over.
	if ( defined( 'WP_REPAIRING' ) ) {
		return true;
	}

	$suppress = $wpdb->suppress_errors();

	/*
	 * Loop over the WP tables. If none exist, then scratch installation is allowed.
	 * If one or more exist, suggest table repair since we got here because the
	 * options table could not be accessed.
	 */
	$wp_tables = $wpdb->tables();
	foreach ( $wp_tables as $table ) {
		// The existence of custom user tables shouldn't suggest an unwise state or prevent a clean installation.
		if ( defined( 'CUSTOM_USER_TABLE' ) && CUSTOM_USER_TABLE === $table ) {
			continue;
		}

		if ( defined( 'CUSTOM_USER_META_TABLE' ) && CUSTOM_USER_META_TABLE === $table ) {
			continue;
		}

		$described_table = $wpdb->get_results( "DESCRIBE $table;" );
		if (
			( ! $described_table && empty( $wpdb->last_error ) ) ||
			( is_array( $described_table ) && 0 === count( $described_table ) )
		) {
			continue;
		}

		// One or more tables exist. This is not good.

		wp_load_translations_early();

		// Die with a DB error.
		$wpdb->error = sprintf(
			/* translators: %s: Database repair URL. */
			__( 'One or more database tables are unavailable. The database may need to be <a href="%s">repaired</a>.' ),
			'maint/repair.php?referrer=is_blog_installed'
		);

		dead_db();
	}

	$wpdb->suppress_errors( $suppress );

	wp_cache_set( 'is_blog_installed', false );

	return false;
}

Conditional tags (all)

Checks