Hitachi, Ltd.

Eisaku Nishiyama

Satoshi Kikuchi

Keiichi Nakane

Hiromichi Ito

Hisashi Hashimoto

Yusuke Hino

A distributed database management system includes a communication network, at least a terminal device including an application program execution unit connected to the communication network, a plurality of information processors connected to the communication network, a plurality of physical databases installed in at least one of the information processors, at least a logical database grouping a plurality of the, physical databases, the logical database being defined by logical database information stored in at least one of the terminal device and the plurality of information processors, at least a table stored in at least one of the physical databases, and a table location searching unit installed in at least one of the terminal device and the plurality of information processors, for searching a table stored in at least one of the physical databases based on the logical database information, the table being requested to access on a logical database, from the application program execution unit.

Distributed database management system including logical database constituted by a group of physical databases

A database access system for a distributed system, in which the database access load is distributed among a plurality of gateways, and an arbitrary character code set can be used for database access. After the lapse of a predetermined time length, processings for particular database access are terminated. An error of a DBMS or a component on the gateway is detected by a client. The gateway detects an error of the client in connection. The client notifies the character code set identification information of the character code used for outputting the request to the gateway, and the gateway converts the character code for the request and a response to the client. The gateway receives an access request, secures the connection with a database access language conversion unit, and sends the language converted to a DBMS. In the absence of a response after the lapse of a predetermined time length, the connection with the database access language conversion unit is terminated and an error is notified to the client. Also, an error monitor request is outputted at regular intervals of time, and an error is notified to the client in the case where there is no response to the error monitor request after the lapse of a predetermined time length.

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Ebina, Japan

Eisaku Nishiyama