A method of assigning transaction timestamps for use with a database that includes temporal data and may include non-temporal data. In the method, a lock is placed on a resource accessed by a first transaction to prevent conflicts with concurrently executing transactions. An access record of the lock mode and a timestamp of the first transaction is created for the resource accessed by the first transaction. The access record is accessed to determine whether a resource that a subsequent transaction accesses conflicts with the resource accessed by the first transaction. A timestamp lower bound or floor is identified for the subsequent transaction when the subsequent transaction accesses a resource that conflicts with the resource access of the first transaction. A timestamp is assigned to the subsequent transaction that is greater than the lower bound. The access record of a lock mode and a transaction timestamp may be created each time a resource is accessed, may be created for resources accessed after a request for CURRENT TIME is made, and/or may be made for resources accessed after an end time of a time interval defined by a request for CURRENT TIME.