This paper explores software design methodologies in the context of creating a simulator and proposes a methodology to design and implement an event-based simulator namely SimMet. SimMet is explored in the context of the development of a complex simulator for simulating real world conditions to use in science, technology and medicine and other simulations. In this paper we interested in event-based approach to create a real world with variety range of event possibilities. The paper first discusses the role of time concept as the cornerstone of a methodical analysis and design phase. In SimMet we use an adaptation of object-oriented methodology to meet time and event concepts in creating a simulator. In the paper we use DBMSS, the simulator that was designed and implemented by SimMet, to test and evaluate SimMet. DBMSS provide a real world environment which is event-based in the test phase of our research. We discuss the architecture of DBMSS and use it to provide arrival transactions to test and evaluate concurrency protocols in database system. We present the comparison of 4 concurrency protocols in variety of conditions and workloads of transactions which is provided by DBMSS. In particular we show that in which conditions each protocol gain over the other protocols and compare the results to the proved results in literature. The results of the comparison show that DBMSS could simulate the real world conditions of arrival transactions and our methodology can be used to create efficient simulated environments