In this paper, the issue of reading the entire database by the broadcast transaction for data broadcasting in mobile environments is addressed. The broadcast transaction is a long-lived read-only transaction which creates significant amount of data conflicts with other concurrent update transactions. Using conventional concurrency control to handle the broadcast transaction is inadequate. Recently, some algorithms are proposed for reading the entire database. However, they suffer from late detection of data conflicts. This leads to many data entities being locked unnecessarily, reducing the availability of data. To solve this problem, an effective protocol based on a data locking approach is devised. Data conflicts can be detected at the early stage of the execution of update transactions by a set of predefined rules. As a result, the lock holding time of data entities is effectively reduced and unnecessary acquisitions of data locks are avoided. The simulation results show that the system performance can be significantly improved.