1. A multi-version concurrency control method in a database, comprising: receiving a data reading request generated by a read transaction, wherein the data reading request is used to request to read a page in the database, and wherein the data reading request comprises a timestamp of the read transaction; reading a current version page of the page that is requested to read by the data reading request when a timestamp of the current version page of the page that is requested to read by the data reading request is less than or equal to the timestamp of the read transaction; and performing page-level rollback using a page pointer of the current version page in a data page link of the page that is requested to read in order to roll back the current version page to a version page, a timestamp of which is less than or equal to the timestamp of the read transaction when the timestamp of the current version page is greater than the timestamp of the read transaction, wherein the data page link comprises a page pointer of each version page of the page that is requested to read, and wherein the page pointer of each version page is used to point to a previous version page of the version page.