No, DBISAM automatically manages all cache refresh and multi-user locking issues transparently. However, it is always good practice to make sure that you take into account locking conflicts and the timeliness of refreshes when developing a multi-user application. Additionally, if you are planning on using the DBISAM database server then you'll need to take into account server administration and many other issues that are specific to using the DBISAM database server for multi-user applications.