Please try this code:
register_activation_hook ( __FILE__, 'on_activate' );
function on_activate() { global $wpdb; $create_table_query = " CREATE TABLE IF NOT EXISTS `{$wpdb->prefix}table1` ( `id` bigint(20) unsigned NOT NULL default '0', `name` text NOT NULL, `address` text NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=utf8; "; require_once( ABSPATH . 'wp-admin/includes/upgrade.php' ); dbDelta( $create_table_query ); }
I hope this is helps you.
Thank you.

Try this code
register_activation_hook ( __FILE__, 'on_activate' ); function on_activate() { global $wpdb; $create_table_query = " CREATE TABLE IF NOT EXISTS `{$wpdb->prefix}table1` ( `id` bigint(20) unsigned NOT NULL default '0', `name` text NOT NULL, `address` text NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=utf8; "; require_once( ABSPATH . 'wp-admin/includes/upgrade.php' ); dbDelta( $create_table_query ); }