function wc_update_200_line_items() {
	global $wpdb;

	// Now its time for the massive update to line items - move them to the new DB tables.
	// Reverse with UPDATE `wpwc_postmeta` SET meta_key = '_order_items' WHERE meta_key = '_order_items_old'.
	$order_item_rows = $wpdb->get_results(
		"SELECT meta_value, post_id FROM {$wpdb->postmeta} WHERE meta_key = '_order_items'"
	);

	foreach ( $order_item_rows as $order_item_row ) {

		$order_items = (array) maybe_unserialize( $order_item_row->meta_value );

		foreach ( $order_items as $order_item ) {

			if ( ! isset( $order_item['line_total'] ) && isset( $order_item['taxrate'] ) && isset( $order_item['cost'] ) ) {
				$order_item['line_tax']          = number_format( ( $order_item['cost'] * $order_item['qty'] ) * ( $order_item['taxrate'] / 100 ), 2, '.', '' );
				$order_item['line_total']        = $order_item['cost'] * $order_item['qty'];
				$order_item['line_subtotal_tax'] = $order_item['line_tax'];
				$order_item['line_subtotal']     = $order_item['line_total'];
			}

			$order_item['line_tax']          = isset( $order_item['line_tax'] ) ? $order_item['line_tax'] : 0;
			$order_item['line_total']        = isset( $order_item['line_total'] ) ? $order_item['line_total'] : 0;
			$order_item['line_subtotal_tax'] = isset( $order_item['line_subtotal_tax'] ) ? $order_item['line_subtotal_tax'] : 0;
			$order_item['line_subtotal']     = isset( $order_item['line_subtotal'] ) ? $order_item['line_subtotal'] : 0;

			$item_id = wc_add_order_item(
				$order_item_row->post_id,
				array(
					'order_item_name' => $order_item['name'],
					'order_item_type' => 'line_item',
				)
			);

			 // Add line item meta.
			if ( $item_id ) {
				wc_add_order_item_meta( $item_id, '_qty', absint( $order_item['qty'] ) );
				wc_add_order_item_meta( $item_id, '_tax_class', $order_item['tax_class'] );
				wc_add_order_item_meta( $item_id, '_product_id', $order_item['id'] );
				wc_add_order_item_meta( $item_id, '_variation_id', $order_item['variation_id'] );
				wc_add_order_item_meta( $item_id, '_line_subtotal', wc_format_decimal( $order_item['line_subtotal'] ) );
				wc_add_order_item_meta( $item_id, '_line_subtotal_tax', wc_format_decimal( $order_item['line_subtotal_tax'] ) );
				wc_add_order_item_meta( $item_id, '_line_total', wc_format_decimal( $order_item['line_total'] ) );
				wc_add_order_item_meta( $item_id, '_line_tax', wc_format_decimal( $order_item['line_tax'] ) );

				$meta_rows = array();

				// Insert meta.
				if ( ! empty( $order_item['item_meta'] ) ) {
					foreach ( $order_item['item_meta'] as $key => $meta ) {
						// Backwards compatibility.
						if ( is_array( $meta ) && isset( $meta['meta_name'] ) ) {
							$meta_rows[] = '(' . $item_id . ',"' . esc_sql( $meta['meta_name'] ) . '","' . esc_sql( $meta['meta_value'] ) . '")';
						} else {
							$meta_rows[] = '(' . $item_id . ',"' . esc_sql( $key ) . '","' . esc_sql( $meta ) . '")';
						}
					}
				}

				// Insert meta rows at once.
				if ( count( $meta_rows ) > 0 ) {
					$wpdb->query(
						$wpdb->prepare(
							"INSERT INTO {$wpdb->prefix}woocommerce_order_itemmeta ( order_item_id, meta_key, meta_value )
							VALUES " . implode( ',', $meta_rows ) . ';', // @codingStandardsIgnoreLine
							$order_item_row->post_id
						)
					);
				}

				// Delete from DB (rename).
				$wpdb->query(
					$wpdb->prepare(
						"UPDATE {$wpdb->postmeta}
						SET meta_key = '_order_items_old'
						WHERE meta_key = '_order_items'
						AND post_id = %d",
						$order_item_row->post_id
					)
				);
			}

			unset( $meta_rows, $item_id, $order_item );
		}
	}

	// Do the same kind of update for order_taxes - move to lines.
	// Reverse with UPDATE `wpwc_postmeta` SET meta_key = '_order_taxes' WHERE meta_key = '_order_taxes_old'.
	$order_tax_rows = $wpdb->get_results(
		"SELECT meta_value, post_id FROM {$wpdb->postmeta}
		WHERE meta_key = '_order_taxes'"
	);

	foreach ( $order_tax_rows as $order_tax_row ) {

		$order_taxes = (array) maybe_unserialize( $order_tax_row->meta_value );

		if ( ! empty( $order_taxes ) ) {
			foreach ( $order_taxes as $order_tax ) {

				if ( ! isset( $order_tax['label'] ) || ! isset( $order_tax['cart_tax'] ) || ! isset( $order_tax['shipping_tax'] ) ) {
					continue;
				}

				$item_id = wc_add_order_item(
					$order_tax_row->post_id,
					array(
						'order_item_name' => $order_tax['label'],
						'order_item_type' => 'tax',
					)
				);

				 // Add line item meta.
				if ( $item_id ) {
					wc_add_order_item_meta( $item_id, 'compound', absint( isset( $order_tax['compound'] ) ? $order_tax['compound'] : 0 ) );
					wc_add_order_item_meta( $item_id, 'tax_amount', wc_clean( $order_tax['cart_tax'] ) );
					wc_add_order_item_meta( $item_id, 'shipping_tax_amount', wc_clean( $order_tax['shipping_tax'] ) );
				}

				// Delete from DB (rename).
				$wpdb->query(
					$wpdb->prepare(
						"UPDATE {$wpdb->postmeta}
						SET meta_key = '_order_taxes_old'
						WHERE meta_key = '_order_taxes'
						AND post_id = %d",
						$order_tax_row->post_id
					)
				);

				unset( $tax_amount );
			}
		}
	}
}