An integrated method for concurrency control in parallel real-time databases has becn proposed in this paper. The nested transaction model has been investigated to offer more atomic execution units and finer grained control within in a transaction. Based on the classical nested locking protocol and the speculative concurrency control approach, a twoshadow adaptive concurrency control protocol, which combines the Sacrifice based Optimistic Concurrency Control(OPT-Sacrifice) and High Priority two-phase locking (HP-2PL) algorithms together to support both optimistic and pessimistic shadow of each sub-transaction, has been proposed to increase the likelihood of successful timely commitment and to avoid unnecessary replication overload.