Abstract: The present invention relates to a network system, the network system of the present invention comprises an authorized client terminal which is connected to a network, a server which is connected to the network, and a firewall which is interposed between the server and the network. The client terminal accesses the server by means of a publicly known protocol via a port having a publicly known port number in the firewall. In the case in which the accessing client terminal is authorized, the server downloads program for realizing effective dedicated protocols solely between the client terminal and itself to the client terminal via the port having the publicly known port number. Furthermore, the server access with the client terminal conducts data communication by executing the program and by means of the dedicated protocols, via the network and the port having the publicly known port number.

Abstract: The present invention relates a database access system comprising: a plurality of database servers, each of which accommodates a database; and an application server which is connected to the above-mentioned plurality of database servers. The application server comprises a plurality of local transaction managers, each of which corresponds to each of the databases, and individually processes transactions for updating the corresponding database; and a distributed transaction manager which individually provides commands for database updating to the transaction managers.