JPH08286960A - System for inquiring distributed database - Google Patents

Abstract

PURPOSE: To fasten the whole processing of a multi-task by releaving the burden of a distributed DB client. CONSTITUTION: When an inquiry is received from an input/output terminal(user) 31, the distributed DB client 3 transfers the inquiry to a cluster server 5. When the inquiry is received, the cluster server 5 discovers the whereabouts of the DB servers 41 , 42 and 4n having the inquired data bases 441 , 442 and 44n . Thereafter, the inquiries to these DB servers 41 , 42 and 4n are executed and also an answer for the inquiries from the DB serbers 41 , 42 and 4n is worked and processed so as to give it to the distributed DB client 3. Therefore, by this configuration, the burden of the distributed DB client 3 is relieved so that the processing delay of another program under execution is surely mitigated in the multi-task processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed database system in which databases are distributed over a computer network, and a client / server type distributed database inquiry system for remotely accessing and inquiring from a plurality of database servers from an arbitrary client. Regarding

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an electrical configuration of a conventional distributed database system of this type. This conventional system includes a distributed database client 1 (hereinafter referred to as a distributed DB client) connected to each other via a communication line, and a plurality of database servers 2 ₁ , 2 ₂ , ..., 2 _n (hereinafter referred to as a DB server). And the distributed DB client 1 and each DB server 2
₁ (2 ₂ , ..., 2 _n ) share the database management function and execute one database application (Japanese Patent Laid-Open Nos. 2-186479 and 5-2049).
73, etc.).

The distributed DB client 1 is a process for requesting a database service, and is an input / output terminal 11
An input / output control program 12, a distributed database control program 13 (hereinafter referred to as a distributed DB control program), and a plurality of remote database access programs 1
4 ₁ , 14 ₂ , ... ((hereinafter referred to as RDA program)
And a communication control program 15.

The DB servers 2 ₁ , 2 ₂ , ... Are process nodes that perform database services (inquiry processing), and are distributed and installed at remote locations, and each has a communication control program 21 and a database management. It has a program 22 (hereinafter referred to as a DB management program), a search program 23, and databases 24 ₁ , 24 ₂ , ... And these plural databases 24
A set of distributed databases is composed of ₁ , 24 ₂ , ...

In the above conventional system configuration, the distributed DB client 1 has an input / output control program 12
When receiving an inquiry input from the input / output terminal (user) 11, the inquiry information is checked, and if there is no error, it is passed to the distributed DB control program 13. Distributed D
In the B control program 13, the location of _one or a plurality of relational DB servers 2 ₁ , 2 ₂ , 2 _n having the designated databases 24 ₁ , 24 ₂ , 24 _n is determined according to the database access destination designation placed in the inquiry information. After clarifying the inquiry information, the related DB servers 2 ₁ , 2 ₂ , 2 _n
The RDA programs 14 ₁ , 14 ₂ and 14 _n corresponding to the number of relational DB servers 2 ₁ , 2 ₂ and 2 _n are disassembled and started. Then, the started RDA programs 14 ₁ , 14 ₂ ,
14 _n is requested to connect with the related DB servers 2 ₁ , 2 ₂ , 2 _n . Each started RDA program 14 ₁ (14 ₂ , 14
_n ) issues an inquiry from the user when connected to the corresponding one of the relation DB servers 2 ₁ (2 ₂ , 2 _n ) via the communication control program 15.

When the search results (response data) from the relational DB servers 2 ₁ , 2 ₂ and 2 _n are returned via the reverse route, the distributed D
The B control program 13 processes the response data in accordance with the request from the user, and then the I / O control program 1
Pass to 2. The input / output control program 12 outputs the processed response data to the input / output terminal 11.

As described above, according to the above-mentioned conventional system, the user does not have to be aware of the locations and configurations of the plurality of DB servers 2 ₁ , 2 ₂ , ... By recognizing that the data exists on its own computer, a plurality of databases 24 ₁ , 24 ₂ ,
You can access ...

[0008]

However, in the above-mentioned conventional distributed database inquiry method, the distributed DB client 1 side accepts an inquiry, searches for the location of the related DB server, and arbitrarily combines and shapes response data.
Since all the search results including display format setting and print format setting are processed, a large load is applied to the distributed DB client 1. Therefore, in particular, when the distributed DB client is operated on a multitasking operating system, there is a problem that the processing speed of another program (application software) being executed is delayed, and its function or operation is restricted. there were.

The present invention has been made in view of the above circumstances, and is a client node (distributed DB client).
The purpose of the present invention is to provide a distributed database query method that can speed up the overall processing of multitasking by reducing the burden on the.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is a client / server provided with a cluster server node for integrally controlling a plurality of database server nodes existing on a computer network. Type of distributed database control method, wherein the cluster server node clarifies the whereabouts of the database server node having each specified database when receiving an inquiry from the arbitrary client nodes to the plurality of databases. , While querying these database server nodes,
It is characterized in that the responses to the inquiries from these database server nodes are processed and then passed to the client node.

The invention according to claim 2 is the distributed database inquiry system according to claim 1, wherein the client node controls the connection with the cluster server node via a communication line. A control program, and an input / output control program for receiving an inquiry to a plurality of databases from the input / output terminal means and outputting a response to the inquiry to the input / output terminal means,
A first remote database access means for transferring the inquiry to the cluster server node using the first communication control program, wherein the cluster server node controls connection with the client node via a communication line. A second communication control program to be executed, a third communication control program for controlling connection to each of the database server nodes via a communication line, and a corresponding database server node using the third communication control program Based on the plurality of second remote database access means for exchanging data with each other and the inquiry transferred from the first remote database access means, the queries are disassembled and rearranged for each designated database server node. Then, the plurality of second remote database access means And a plurality of database server nodes, and a plurality of server centralized control means for processing the response to the inquiry returned from each of the database server nodes, and the plurality of database servers. The node manages the fourth communication control program for controlling connection with the cluster server node via a communication line, a database, and the database, and provides an answer to an inquiry from the multiple server central control means. It is characterized by comprising a database management program.

The invention according to claim 3 is characterized in that a second cluster server node for centrally controlling a plurality of database server nodes existing on a computer network;
A client / server type distributed database control system comprising a plurality of database server nodes that also exist on a computer network and a first cluster server node that integrally controls the second cluster server node. When one cluster server node receives an inquiry from a given client node to a plurality of databases, the database server nodes having respective designated databases, and these database server nodes collectively control the second cluster server node. In the state of being set, the location of the second cluster server node is clarified, and then the database server node and / or the second cluster server node are inquired and the database server node Or / and after processing the answers to the inquiry from the second cluster server node, it is characterized in that passed to the client node.

The invention according to claim 4 is the distributed database inquiry method according to claim 3, wherein the client node controls the connection with the cluster server node via a communication line. A control program, and an input / output control program for receiving an inquiry to a plurality of databases from the input / output terminal means and outputting a response to the inquiry to the input / output terminal means,
A first remote database access means for transferring the inquiry to the cluster server node using the first communication control program, wherein the first cluster server node communicates with the client node via a communication line. A second communication control program for controlling connection, and each of the above database server nodes or / or via a communication line.
And a third communication control program for controlling connection with the second cluster server node, and using the third communication control program to exchange data with the corresponding database server node or second cluster server node. A plurality of second remote database access means, and the first
After disassembling and rearranging the queries for each of the designated database server node and the second cluster server node based on the query transferred from the remote database access unit of Inquiries are made to the plurality of database server nodes or / and the second cluster server nodes by using the reply to the inquiries returned from the respective database server nodes and / or the second cluster server nodes. A central processing unit for processing a plurality of servers, wherein the second cluster server node performs a connection control with the first cluster server node via a communication line; Each database server above via communication line A sixth communication control program that controls the connection to, using a communication control program of the sixth,
A plurality of third remote database access means for exchanging data with the corresponding database server node,
After disassembling and re-arranging the inquiry for each designated database server node based on the inquiry transferred from the second remote database access means,
A second plurality of inquiries to the plurality of database server nodes using the plurality of third remote database access means and a processing of an answer to the inquiry returned from each of the database server nodes. A server centralized control means, and the plurality of database server nodes, a fourth communication control program for controlling connection with the cluster server node via a communication line, a database,
It is characterized by comprising a database management program for managing the database and providing an answer to an inquiry from the multiple server centralized control means.

[0014]

When the client node receives an inquiry from the user, the client node transfers the inquiry to the cluster server node. When the cluster server node receives this inquiry, after revealing the whereabouts of the database server node having the inquired database,
Inquiries are made to these database server nodes, and the responses to the inquiries from these database server nodes are processed and passed to the client node. Therefore, according to the configuration of the present invention, the load on the client node (distributed DB client) can be reduced. Therefore, when the client process is operated on a multitasking operating system, it is possible to surely reduce the delay in the processing of other programs being executed.

Further, a multi-stage distributed database can be realized by adopting a form (nested structure) in which the cluster server node makes an inquiry to another cluster server node having a plurality of database server nodes under it. With such a nest structure, distributed placement management of databases becomes much easier, and the load on each database server node can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is an electrical block diagram showing the overall configuration of a distributed database system that operates according to the distributed database inquiry method according to the first embodiment of the present invention. The distributed database system of this example includes a distributed DB client 3 and a plurality of DB servers 4 connected to each other via a communication line.
_1, 4 _2, ... and these DB server 4 _1, 4 _2, and a cluster server 5 for governing .... The difference of the distributed database system of this example from that of the conventional one is that the distributed DB control program 13 having a large load is removed from the components of the distributed DB client 1 (FIG. 7), and instead, as shown in FIG. The point is that the cluster server 5 having the multi-server centralized control program 52 (which roughly corresponds to the distributed DB control program 13) is provided.

The distributed DB client 3 accepts an inquiry (database access request) from a user,
It is a multi-task compatible node computer that passes the inquiry result (response data) to the user, and has an input / output terminal 31, an input / output control program 32, and a single RDA.
The program 33 and the first communication control program 34 are included. Since the distributed DB client 3 is a multitasking node computer, a plurality of application software can be executed in parallel.

The input / output terminal 31 is composed of a keyboard, a mouse and the like for the user to input inquiry information, a display device and a printer for outputting the inquiry result. When the input / output control program 32 receives the inquiry input from the input / output terminal 31, it checks the inquiry information, and if there is no error, RDA
The RDA program 3 is activated while the program 33 is activated and the inquiry information is passed to the RDA program 33 as it is.
When the response data is received from 3, the screen display position and the paper print position are set in the display device or printer of the input / output terminal 31 and output. It also controls the interrupt request from the input / output terminal 31. RDA program 33
Is a program for accessing the cluster server 5 connected to the communication line via the first communication control program 34 without being aware of the physical configuration of lower layer communication. The first communication control program 34 is a program dedicated to normal communication management, transmits inquiry information output from the RDA program 33 to the cluster server 5 via a communication line, and sends response data from the cluster server 5. RDA program 33 connected to
Return to.

Next, the cluster server 5 centrally manages the locations of the plurality of DB servers 4 ₁ , 4 ₂ , ... And requests the search from the distributed DB client 3 to the related DB servers 4 ₁ , 4 ₂ , 4.
A node computer that transfers to the distributed DB client 3 after processing the search results (response data) supplied from the relational DB servers 4 ₁ , 4 ₂ and 4 _n according to the user's request while transferring to _n Yes, second communication control program 5
1, multiple server centralized control program 52, multiple R
DA program 53 _1, 53 _2, ..., and a third communication control program 54. Cluster server 5
Is a client that requests a database access from the viewpoint of the DB servers 4 ₁ , 4 ₂ , ..., But from the viewpoint of the distributed DB client 3, the distributed database 44
_1, 44 _2, functions as a centralized DB server for centralized control of .... The second communication control program 51 is a program that performs normal communication management, and activates the multiple server centralized control program 52 in response to a search request from the distributed DB cluster 3 to communicate with the communication destination (first distributed DB client). An actual session is connected to and disconnected from the communication control program 34).

When the inquiry information is transferred from the distributed DB client 3 via the second communication control program 51, the multi-server centralized control program 52 is designated in accordance with the database access destination designation placed before the inquiry information. database 44 _1, 44 _2, 4
One or more relational DB servers 4 ₁ , 4 ₂ having 4 _n ,
After clarifying the whereabouts of 4 _n , contact information D
The RDA programs 53 ₁ , 5 are decomposed into B servers 4 ₁ , 4 ₂ , 4 _n to match the number of relational DB servers 4 ₁ , 4 ₂ , 4 _n.
3 ₂ and 53 _n are activated. Then, the relational DB servers 4 ₁ , 4 are added to the started RDA programs 53 ₁ , 53 ₂ , 53 _n .
Request connection with 4 ₂ and 4 _n . On the other hand, the relation DB server 4
_When the search results (response data) from ₁ , 4 ₂ and 4 _n are returned in the reverse route, the response data is processed (shaped) according to the request from the user, and then the second communication control program 5
1 to the distributed DB client 3.

The RDA programs 53 ₁ , 53 ₂ , ... Are related DB servers 4 ₁ , 4 ₂ , at remote locations connected to a communication line without being aware of the physical configuration of lower layer communication.
4 _n (DB management program 42) is a program for accessing a search request from a user according to a protocol (communication protocol such as RDA general standard or RDA specialization standard) and receiving the result. . In addition,
Different DB servers can be accessed using a specific protocol. The third communication control program 54 is a program dedicated to normal communication management, and the inquiry information output from the RDA programs 53 ₁ , 53 ₂ , 53 _n is related DB servers 4 ₁ , 4 ₂ via a communication line. , 4 _n
And the response data from the relational DB servers 4 ₁ , 4 ₂ , 4 _n to the RDA programs 53 ₁ , 5 being connected.
Return to 3 ₂ , 53 _n .

Next, the DB servers 4 ₁ , 4 ₂ , ... Are node computers that provide database services, are distributed in remote locations, and each have a fourth communication control program 41 and Database management program 42 (hereinafter referred to as DB management program)
, Search program 43, and databases 44 ₁ , 4
4 ₂ , ... And. Then, the plurality of databases 44 _1, 44 _2, ... distributed database by is configured. Fourth communication control program 41
Is a program that performs normal communication management, and activates the DB management program 42 in response to a search request from the cluster server 5 to perform actual session connection and disconnection with the cluster server 5. DB management program 42
Is a search program 4 in response to a search request from the cluster server 5 input via the fourth communication control program 41.
3 is activated to perform data transmission between the search program 43 and the fourth communication control program 41. In addition, it terminates the search program 43 when a search is requested and gives a processing instruction when a line failure occurs. The search program 43 is actually the database 44.
It is a program for searching ₁ , 44 ₂ , ..., And returns the search result to the cluster server 5 that made the search request.

Next, referring to FIGS. 1 to 4, the operation of this example will be described by taking as an example the case where a database distributed in a wide area such as a university library system is searched through a communication line. Will be described. Distributed DB client 3
When an inquiry (access request) to the database is issued from the input / output terminal (user) 31, the input / output control program 32 first causes the input / output terminal 31 to display a database selection screen which is an initial screen. Figure 2
It shows a case where the user selects five of A, D, L, K, and E by referring to the names of all university libraries of the system displayed on the initial screen. By pressing the Enter key after selecting library, input and output control program 32 requests database 44 ₁ library five chosen RDA program 33, 44 _2, ..., inquiries to 44 _n (access request) To do. The requested RDA program 33 is
Via the first and second communication control programs 34, 51,
It is connected to the multiple server centralized control program 52 of the cluster server 5 which is associated one to one. When the connection to multiple servers centralized control program 52 according to RDA program 33 is made, RDA program 33, the database 44 ₁ of five libraries, 44 _2, ..., multiple servers centralized control query (access request) to 44 _n Program 5
Transfer to 2.

The multiple servers centralized control program 52, a database 44 ₁ library of the selected five, 44 _2,
When receiving an inquiry (access request) to 44 _n , the specified databases 44 ₁ , 4 are specified in accordance with the database access destination specification placed in the inquiry information.
DB server 4 _{1 of} the partner library having 4 ₂ , ..., 44 _n
4 ₂ , ..., 4 _n , after clarifying the whereabouts of the inquiry information, the DB server 4 ₁
4 ₂ , ..., 4 _n are disassembled for each, and DB server 4 of the partner library
_1, 4 _2, ..., 4 _n commensurate with the number of five RDA programs 53 _1, 53 _2, ..., to start the 53 _n. Then, the five activated RDA programs 53 ₁ , 53 ₂ , ..., 53
_n is the DB server 4 ₁ , 4 _{2 of} each partner library,
…, Request connection with 4 _n . Each R requested
The DA programs 53 ₁ , 53 ₂ , ..., 53 _n are independently DBs of the DB servers 4 ₁ , 4 ₂ , ..., 4 _n of the respective libraries via the third and fourth communication control programs 54, 41.
Connect with the management program 42. Each RDA program 53 _1, 53 _2, ..., 53 _n is DB server 4 ₁ connection can have libraries, 4 _2, ..., 4 when Results _n (response data) is transmitted, the search The result is passed to the multi-server centralized control program 52. The multi-server centralized control program 52 includes five RDA programs 53 ₁ ,
When the search results are received from all of 53 ₂ , ..., 53 _n , these search results are processed (shaped), and then the RDA program 33 of the distributed DB client 3 is executed via the second and first communication control programs 51 and 34. Transfer to. The RDA program 33 passes the processed search result to the input / output control program 32. The input / output control program 32 is RDA
When the search result is received from the program 33, since it has already been processed, the screen display position is set on the display device of the input / output terminal 31 and the hit number display screen is displayed on the input / output terminal 31.
To display.

Then, when the user inputs all the materials related to management as the first to the search word input screen and instructs the search, the instructions are sent to the DB servers 4 ₁ , 4 ₂ , …, Given to 4 _n . When the search result returns in the reverse route and in the processed state, the input / output control program 32 displays the number of replies in the latest column of the hit number display screen. Fig. 3 shows the results of No. 1 moved to the previous column when all materials related to the management system of No. 2 after No. 1 are input and executed as search words on the hit count display screen. The result of No. 2 is displayed in the latest column. Next, when the user selects No. 4 as the database name on the hit count display screen and requests a search, the input / output control program 32 causes the search request to go through the above-mentioned route and perform centralized control of a plurality of servers of the cluster server 5. Transfer to program 52. When the centralized control program for multiple servers 52 receives the search request, the RDA program 53 _n connected to the fourth university library
Is selected to request the DB server 44 _n of this library to display the contents of all the materials related to the management system. FIG. 4 is a diagram showing an example of a search result display screen displayed by the input / output control program 32 that has been searched for by this request and has received a response.

According to the above configuration, the cluster server 5 side performs all the processing (combining, shaping, etc.) of the search result (response data) from the search for the location of the relational DB server. There is no load. Therefore, when operating the distributed DB client on a multitasking operating system, it is possible to reliably reduce the delay in the processing of other programs (application software) that are being executed.

Further, the cluster DB server 4 _1, 4 _2, ... public databases 44 _1, 44 _2, ..., as shown in FIG. 5, all of which these DB server 4 _1, 4 _2, ... the overall control Virtual public databases 55 ₁ , 55 ₂ , of the server 5,
Can be thought of as, so the distributed DB client 3
The (user) is the public database 5 of the cluster server 5.
It suffices to recognize only 5 ₁ , 55 ₂ , ..., It is not necessary to recognize the public databases 44 ₁ , 44 ₂ , ... Of the plurality of DB servers 4 ₁ , 4 ₂ , ... Database management becomes much easier.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is an electrical block diagram showing the overall configuration of a distributed database system that operates according to the distributed database inquiry method of the second embodiment of the present invention. The configuration of the second embodiment differs from that of the first embodiment described above in that the DB server 4 _n installed in an arbitrary node
Instead of (FIG. 1), a cluster server 5a and a plurality of DB servers 4a ₁ and 4 connected to the cluster server 5a.
a _2, a ... provided lies in that the nested (hereinafter, referred to as nested nodes nodes such nesting is incorporated). For nodes other than nested nodes,
This is exactly the same as the system configuration (FIG. 1) of the first embodiment.
That is, the system configuration of the second embodiment can be realized by changing only the nest node from the system configuration of the first embodiment, and other than the nest node, the distributed DB client 3,
Cluster Server 5 and the DB server 4 _1, 4 ₂ can be realized without changing even one ... of. According to the configuration of the second embodiment, distributed allocation management of databases becomes much easier, and the load on each DB server can be reduced.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific structure is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the present invention. Also included in the present invention. For example, in the above-described first embodiment, the RDA of the distributed DB client 3
The case where the program 33 can connect only to the cluster server 5 fixedly associated with one-to-one has been described, but the program 33 may connect to any one cluster server. Further, in the above-mentioned second embodiment, there is no restriction on nesting of cluster servers.

[0030]

As described above, according to the distributed database inquiry method of the present invention, the cluster server node for integrally controlling the plurality of database server nodes is provided, so that the load on the client node can be reduced. Therefore, when the client process is operated on a multitasking operating system, it is possible to remarkably reduce the processing delay of other programs being executed.

A multi-stage distributed database can be realized by adopting a form (nested structure) in which the cluster server node makes an inquiry to another cluster server node having a plurality of database server nodes under it. With such a nest structure, distributed placement management of databases becomes much easier, and the load on each database server node can be reduced.

[Brief description of drawings]

FIG. 1 is an electrical block diagram showing an overall configuration of a distributed database system that operates according to a distributed database inquiry method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a display screen for explaining the operation of the embodiment.

FIG. 3 is a diagram showing an example of a display screen for explaining the operation of the embodiment.

FIG. 4 is a diagram showing an example of a display screen for explaining the operation of the embodiment.

FIG. 5 is a diagram for explaining an effect of the same embodiment.

FIG. 6 is an electrical block diagram showing the overall configuration of a distributed database system that operates according to the distributed database inquiry method of the second embodiment of the present invention.

FIG. 7 is a block diagram showing an electrical configuration of a conventional distributed database system of this type.

[Explanation of symbols]

3 distributed DB client (client node) 31 input / output terminal (input / output terminal means) 32 input / output control program 33 RDA program (first remote database access means) 34 first communication control program (first communication control program) 4 ₁ , 4 ₂ , ..., 4 _n DB server (database server node) 4 a ₁ , 4 a ₂ , ... DB server (database server node) 41 Fourth communication control program (fourth communication control program) 42 DB management program (database) management program) 43 search program _{44 1, 44 2, ...,} 44 n database 5 cluster servers (cluster server node, the first
Cluster server node) 5a Cluster server (second cluster server node) 51 Second communication control program (second communication control program) 52 Multiple server central control program (multiple server central control means) 53 ₁ , 53 ₂ , ... , 53 _n RDA program (second remote database access means) 54 Third communication control program (third communication control program)

Claims (4)

[Claims] 1. A client / server type distributed database control system comprising a cluster server node for integrally controlling a plurality of database server nodes existing on a computer network, wherein the cluster server node is an arbitrary client node. When you receive an inquiry from multiple databases from
After clarifying the whereabouts of the database server nodes having the respective designated databases, making inquiries to these database server nodes and processing the responses to the inquiries from these database server nodes, and then the client A distributed database inquiry method characterized by being passed to nodes. 2. The client node receives a first communication control program for controlling connection with the cluster server node via a communication line and an inquiry to a plurality of databases from an input / output terminal means, and the inquiry is made. And a first remote database access means for transferring the inquiry to the cluster server node by using the first communication control program. The server node includes a second communication control program for controlling connection with the client node via a communication line, and a third communication control program for controlling connection with each of the database server nodes via a communication line, Using the third communication control program, the corresponding database server Based on the plurality of second remote database access means for exchanging data with the node, and the inquiry transferred from the first remote database access means, the queries are disassembled and rearranged for each designated database server node. After doing
Centralized control of a plurality of servers for making an inquiry to the plurality of database server nodes by using the plurality of second remote database access means and processing an answer to the inquiry returned from each of the database server nodes. A plurality of database server nodes, wherein the plurality of database server nodes manage a database and a fourth communication control program for controlling connection with the cluster server node via a communication line; The distributed database inquiry system according to claim 1, further comprising a database management program for providing a response to an inquiry from the server centralized control means. 3. A second cluster server node that integrally controls a plurality of database server nodes existing on a computer network, and a plurality of database server nodes and a second cluster server node also existing on the computer network. A client / server type distributed database control system comprising a first cluster server node for controlling, wherein the first cluster server node receives an inquiry to a plurality of databases from an arbitrary client node, Database server nodes having respective designated databases, and when these database server nodes are in a state of being totally controlled by the second cluster server node, after clarifying the whereabouts of the second cluster server node, these Inquiries are made to the database server node and / or the second cluster server node, and the responses to the inquiries from these database server nodes and / or the second cluster server nodes are processed and passed to the client node. A distributed database inquiry method characterized in that 4. The client node receives a first communication control program for controlling connection with the cluster server node via a communication line, and an inquiry to a plurality of databases from an input / output terminal means, and the inquiry. An input / output control program for outputting a reply to the input / output terminal means, and a first remote database access means for transferring the inquiry to the cluster server node using the first communication control program. The first cluster server node includes a second communication control program for controlling connection with the client node via a communication line, and each of the database server nodes and / or the second cluster server node via a communication line. A third communication control program for controlling connection, and the third communication control program A plurality of second remote database access means for exchanging data with the corresponding database server node or second cluster server node using RAM, and the inquiry transferred from the first remote database access means. Based on the above, after disassembling and rearranging the queries for each designated database server node and second cluster server node, using the plurality of second remote database access means, the plurality of database server nodes and / or the plurality of database server nodes. First multiple server centralized control means for making an inquiry to two cluster server nodes and processing an answer to the inquiry returned from each of the database server nodes and / or the second cluster server node. Comprising the second class The data server node includes a fifth communication control program for controlling connection with the first cluster server node via a communication line, and a sixth communication control program for controlling connection with the database server nodes via the communication line. A communication control program and a plurality of third remote database access means for exchanging data with the corresponding database server node using the sixth communication control program, and transfer from the second remote database access means. After disassembling and rearranging the queries for each specified database server node based on the queries
A second plurality for making an inquiry to the plurality of database server nodes using the plurality of third remote database access means and processing an answer to the inquiry returned from each of the database server nodes. Centralized server control means, and the plurality of database server nodes, a fourth communication control program for controlling the connection with the cluster server node via a communication line, a database, and managing the database and 4. The distributed database inquiry system according to claim 3, further comprising: a database management program that provides an answer to an inquiry from the multiple server centralized control means.