maybe_create_table( string $table_name, string $create_ddl )

Creates a table in the database if it doesn’t already exist.

Description

This method checks for an existing database and creates a new one if it’s not already present. It doesn’t rely on MySQL’s "IF NOT EXISTS" statement, but chooses to query all tables first and then run the SQL statement creating the table.

Parameters

$table_name

(string) (Required) Database table name to create.

$create_ddl

(string) (Required) SQL statement to create table.

Return

(bool) If table already exists or was created by function.

Source

File: wp-admin/includes/upgrade.php 

function maybe_create_table($table_name, $create_ddl) {
	global $wpdb;

	$query = $wpdb->prepare( "SHOW TABLES LIKE %s", $wpdb->esc_like( $table_name ) );

	if ( $wpdb->get_var( $query ) == $table_name ) {
		return true;
	}

	// Didn't find it try to create it..
	$wpdb->query($create_ddl);

	// We cannot directly tell that whether this succeeded!
	if ( $wpdb->get_var( $query ) == $table_name ) {
		return true;
	}
	return false;
}

Expand Source Code View on GitHub

Related

Uses

Uses
Uses Description
wp-includes/wp-db.php: wpdb::get_col()

Retrieve one column from the database.
wp-includes/wp-db.php: wpdb::query()

Perform a MySQL database query, using current database connection.
wp-includes/wp-db.php: wpdb::prepare()

Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
wp-includes/wp-db.php: wpdb::esc_like()

First half of escaping for LIKE special characters % and _ before preparing for MySQL.
wp-includes/wp-db.php: wpdb::get_var()

Retrieve one variable from the database.

Changelog

Changelog
Version Description
WP-1.0.0 Introduced.