JPH09198293A - Wide area data base management system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To access a data base at satisfactory response speed by each client existing at a geographical distance. SOLUTION: At each of sites A and B, each of a data bases D-A and D-B is possessed. In each data base, intra-area information circulating in only one's own site and common information circulating at both sites are stored. The update status of the data bases D-A and D-B is monitored by the gateways G-A and G-B for information exchange of each site. When the update of common information is performed, the receipt and delivery of update information are performed between respective gateways for information exchange via a communication line 2 and the identification of the common information on the data base of each site is kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide area database management system in which regional database management systems distributed in a plurality of areas are connected via communication lines.

[0002]

2. Description of the Related Art FIGS. 5 and 6 exemplify the configuration of a conventional general database management system. Among these, the one shown in FIG. 5 is a file server S that manages access to the database and a terminal device C of the client.
Are connected via a LAN (local area network) 1. Although many terminal devices are actually connected to the LAN 1, the illustration is omitted because the drawing becomes complicated. In this configuration, each client can freely access the database via the LAN 1 and the file server S.

On the other hand, the system shown in FIG. 6 allows each client located geographically distant to access a common database. In the example shown in FIG. 6, at a certain site (region) A, the file server S-A
Is installed, and the file server S-A and the terminal device C-A are connected by the LAN 1A. Further, at another site B geographically distant from this area, the terminal device CB is connected by the LAN 1B.
The sites are connected to each other via the communication line 2. In this configuration, the client of the site A can access the database via the LAN 1A and the file server SA. On the other hand, the client at the site B will access the database via the communication line 2.

[0004]

Among the above-mentioned database management systems shown in FIG. 5, the LAN connecting the database and each client generally has a high transmission capacity, and therefore each client is connected via the LAN. The database can be accessed with almost no restriction on the speed of the information transmission.

However, in the case of the database management system for wide area clients as shown in FIG. 6, only the client of the site where the database is installed can access the database only through the LAN. , Clients of sites other than this site must access the database via the communication line. The transmission capacity of the communication line connecting the sites is lower than the transmission capacity of the LAN within the site. For this reason, there has been a problem that a client at a site distant from the database cannot access the database at a satisfactory response speed.

The present invention has been made in view of the circumstances described above, and provides a wide area database management system in which each client existing geographically apart can access a database at a sufficient response speed. Is intended.

[0007]

The invention according to claim 1 is
A wide area database management system comprising a plurality of regional database management systems, each of which is distributed in a plurality of areas and which provides information services to clients within a jurisdiction area, connected via a communication line. Each regional database management system has a database that stores regional information that is distributed only in that region and common information that is distributed in that region and other regions, and is stored in the database of one of the regional database management systems. When the updated common information is updated, the updated content is transmitted via the communication line to the database of the other regional database management system so as to match the updated common information. A wide area database management system characterized by updating stored common information And effect.

According to the second aspect of the present invention, a plurality of intra-regional database management systems, each of which is distributed over a plurality of regions and provides information services to clients within the jurisdiction, are connected via a communication line. In the wide area database management system, each of the regional database management systems stores in the database a database storing regional information distributed only in the region and common information distributed in the region and other regions. When the stored common information is updated, the other area database management system is notified of the update information indicating the update content of the common information via the communication line, and the other area is updated via the communication line. When the update information is received from the internal database management system, the common information in the database according to the update information The wide-area database management system characterized by comprising information exchange means to update the gist.

According to a third aspect of the present invention, the information exchanging means of each regional database management system receives a common information update request from a client in the region and updates the common information corresponding to the update request. 3. The wide area database management according to claim 2, wherein the information exchange means of the other area database management system is prohibited from accepting another update request for the common information until the update is completed. The system is the gist.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments will be described to make the present invention easier to understand. Such an embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

A. First Embodiment FIG. 1 shows the configuration of a wide area database management system according to a first embodiment of the present invention. This wide area database management system is configured by connecting a regional database management system provided at site A and a regional database management system provided at site B by a communication line 2. Here, the intra-regional database management system at the site A has a database DA, and a file server SA that manages access to this database and a terminal device CA of the client.
And are connected via LAN1-A. On the other hand, the intra-regional database management system at site B also has its own database DB, and the file server SB for managing access to this database and the terminal device CB of the client are connected by LAN1-B. It is connected.

The database owned by the site A is accessed only by the clients within the site A, and the regional information distributed only within the site A and the clients of both the sites A and B are accessed through the sites A and B. The common information distributed on both sites is stored.
Similarly, the database owned by the site B also stores regional information distributed only within the site B and common information distributed at both sites.

The database management system in each area of the sites A and B is a gateway for information exchange GA.
And GB respectively, and when a client of each site accesses the database, information is exchanged between the client and the database via each information exchange gateway. In addition, each information exchange gateway constantly monitors the update status (information deletion, addition, change, etc.) of the database of the site in which it is provided. Then, when the common information in the database of one site is updated, each information exchange gateway exchanges information regarding the updated content via the communication line 2 to synchronize the stored content of the database, that is, ,
The common information of the other site is updated so as to match the updated common information of the one site.

FIG. 2 shows the flow of processing when the client in the site A requests the information update from the terminal device CA. Hereinafter, the operation of the present embodiment will be described with reference to FIG.

First, the information update request is delivered to the information exchange gateway GA in the site A (step S1). The information exchange gateway G-A responds to the information update request, and updates the corresponding information in the database D-A via the file server S-A (step S2). Here, the database stores the intra-regional information distributed only on its own site (site A) and the common information distributed on both A and B sites, but the information update request of the client is intended for which information. Regardless of whether the request is made, the information update corresponding to the request is performed in this step S2. That is, the client achieves the purpose of updating information by terminating step S2 regardless of whether the target information is intra-regional information or common information.

Next, the information exchange gateway GA determines whether the updated information is common information distributed at both sites A and B or local information distributed only within the site A.
That is, it is determined whether or not database synchronization is necessary (step S3). If the result of this determination is "NO", then the entire processing corresponding to the information update request is completed.

On the other hand, the determination result of step S3 is "YE
S ”, the information exchange gateway GA
Sends update information indicating the update content made to the common information to the information exchange gateway GB of the site B via the communication line 2 (step S4). The information exchange gateway GB that has received this update information updates the common information in the database DB based on this update information via the file server SB, and the site B
The content of the common information of the above is matched with the content of the common information of the site A (step S5). In this way, the databases of both sites are synchronized, and the entire processing corresponding to the information update request from the client is completed.

As described above, in this embodiment, each client can update the common information shared with other sites by updating the database of the site to which it belongs, and exchange information thereafter. By the function of the gateway, the common information of each site is synchronized. Therefore, it is possible to realize database management for a wide range of clients without sacrificing the response speed seen from the clients. Also, since the database of each site stores common information that is distributed between other sites as well as its own site, if the client registers as a user on the file server of its own site,
You can exchange common information with clients on any site.

B. Second Embodiment As shown in the first embodiment, in the wide area database management system according to the present invention, each client accesses only the database of the site to which it belongs, so that each client can use only its own site. It is possible to access not only the information in the area that is distributed but also the common information that is distributed between each site.

However, when each client having different sites accesses independently the same common information stored in different databases, the number of clients is large and the common information is frequently updated. In such a situation, there is a possibility that inconsistency may occur in the common information between the sites.

That is, for example, in the first embodiment, when the client of the site A and the client of the site B request the update of the common information between the sites A and B at approximately the same time, the client of the site A at the site A After updating the common information according to the request from the site B
While the common information is updated in response to the request from the client of the site B, the common information is updated in response to the request from the client of the site B in the site B, and then the request from the client of the site A is updated. It is possible that the common information is updated accordingly. If such information update is performed, in the worst case, the common information between the sites A and B will not match.

The second embodiment described below provides a wide area database management system which prevents the occurrence of such inconvenience.

FIG. 3 shows the configuration of this embodiment. In this wide area database management system, the regional database management systems provided at the sites A, B and C are connected to the communication line 2.
Are connected by. Similar to the first embodiment, the intra-regional database management system at each site has databases D-A, D-B and D-C, respectively. In the database D-A of the site A, regional information distributed only on the site A, common information distributed on the sites A and B, common information distributed on the sites A and C, sites A and B,
Common information distributed in C is stored therein. The same applies to other sites, and the in-region information and common information shown in the figure are stored in each database. Information exchange gateways G-A, G-B and G- at each site
C has the function described in the first embodiment,
When the terminal device in the own site updates the common information, it has a function of controlling the information exchange gateway of the other site via the communication line 2 so as not to cause the inconvenience. Other than that, the configuration of the database management system in each area is the same as that described in the first embodiment, and thus the description thereof is omitted.

The operation of this embodiment will be described below. First, a terminal device in the site A outputs an update request D1 for the in-region information corresponding to the site A, and then another terminal device in the site A outputs an update request D2 for the in-region information. The operation in this case will be described.

In this case, the information exchange gateway GA
First, in response to the update request D1, the file server S-A
The information in the area in the database D-A is updated via. After this update is completed, the information exchange gateway G
-A updates the in-region information in the database DA through the file server SA in response to the update request D2.
The information exchange gateway GA does not accept the update request for the in-region information during the period in which the in-region information is updated according to each update request, and does not accept the update request for the in-region information to the terminal device that has sent the request. Indicates to wait. Then, after the update of the in-region information according to each update request is completed, the request from the waiting terminal device is accepted.

Next, a terminal device in the site B outputs an update request D3 about the common information of the sites B and C, and after a slight delay, the terminal device in the site C outputs the update request D3.
The operation when the update request D4 for the C common information is output will be described.

In this case, first, the information exchange gateway G-B of the site B receives the update request D3 from the terminal device in the site. Information exchange gateway GB
Detects that the update request D3 is intended for the common information of the sites B and C, the common information of the sites B and C is sent to the information exchange gateway GC of the site C via the communication line. A wait request RQ indicating that it should wait without accepting an update request for the purpose is sent. At the site C, as described above, the update request D4 intended for the common information of the sites B and C is output from the terminal device, but at this time, the information exchange gateway GC receives the waiting request RQ. , Rejects the update request D4, and instructs the terminal device that has sent this update request to wait. In this case, the information exchange gateway GC rejects only the update request for the common information of the sites B and C.
The update request for other information is accepted by the information exchange gateway GC, and the information corresponding to the update request is updated.

On the other hand, in the site B, the information exchange gateway G-B updates the common information of the sites B and C in the database D-B through the file server SB based on the update request D3. To do. Next, the information exchange gateway GB sends update information indicating the content of this update to the information exchange gateway GC of the site C via the communication line 2.

Information exchange gateway GC at site C
On the basis of this update information, through the file server S-C, the sites B and C in the database D-B
Common information of is updated. In this way, the update process based on the update request D3 is completed for each piece of common information held by each of the sites B and C.

Information exchange gateway GC at site C
Cancels the standby instruction that has been issued to the terminal device when the update process is completed. As a result, the update request D4 is output again from the terminal device.

When the information exchange gateway GC detects that the update request D4 is intended for the common information of the sites B and C, the information exchange gateway GC of the site B via the communication line. A standby request RQ is sent to B indicating that it should stand by without accepting an update request intended for the common information of sites B and C.

As a result, at the site B, even if an update request for the common information of the sites B and C subsequently occurs, the request is rejected. Then, the common information corresponding to the update request D4 is updated at the site C, and when the update information indicating the updated content is sent from the site C to the site B, the common information corresponding to the update request D4 is also transmitted at the site B. Updates are made. By completing this update,
Again, the update request for the common information of the sites B and C is ready to be processed.

The case where the common information distributed at the two sites is updated has been described above as an example. When the terminal of a certain site outputs an update request intended for the common information of the sites A, B, and C. The same is true for. That is, in this case, the information exchange gateway of the relevant site should wait for the information exchange gateways of all other sites without accepting an update request for the common information of the sites A, B, and C. A request to that effect is sent, the common information is updated at the relevant site in response to the update request, the common information is also updated at other sites, and then the standby is released.

As described above, in the present embodiment, even under the situation where each client at different sites frequently outputs a common information update request, the common information of each site is sent to each update request in exactly the same order. Since the corresponding update processing is performed, the identity of the common information of each site is secured.

C. Third Embodiment In each of the above embodiments, an information exchange gateway is provided for each site. In the present embodiment, as illustrated in FIG. 4, only one site A is provided with the information exchange gateway GA. In this configuration, all update requests for common information output from the clients of each site are collected in the information exchange gateway GA, and the information exchange gateway G-A allows the common information in the database of each site to be collected. Will be updated. For common information, the response speed is sacrificed because it is accessed via the communication line, but since the common information is updated by one information exchange gateway, the identity of the common information held by each site is guaranteed. Secured by.

[0036]

As described above, according to the present invention, the database is held in each region, and the common information in each region is kept identical by exchanging the updated contents through the communication line. Since this is done, there is an effect that each client existing geographically apart can access the database at a sufficient response speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a wide area database management system according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the embodiment.

FIG. 3 is a diagram showing a configuration of a wide area database management system according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a wide area database management system according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional database management system.

FIG. 6 is a diagram showing a configuration of a conventional database management system.

[Explanation of symbols]

1 ... communication line, S-A, S-B ... site, C-A, C
-B ... Terminal device, S-A, S-B ... File server, D-A, D-B ... Database, G-A, G-B
...... Information exchange gateway (information exchange means),

Claims (3)

[Claims] 1. A wide area database management system comprising a plurality of regional database management systems, each of which is distributed over a plurality of regions and which provides information services to clients within its jurisdiction, connected via communication lines. The database management system in each area has a database storing information in the area that is distributed only in the area and common information that is distributed in the area and other areas. When the common information stored in the system database is updated,
By transmitting the updated content via the communication line, the common information stored in the database of the other regional database management system is updated so as to match the updated common information. Characteristic wide area database management system. 2. A wide area database management system, which is distributed over a plurality of areas and is connected through a communication line to a plurality of area database management systems for providing information services to clients within the jurisdiction area. The database management system for each area stores a database that stores area information that is distributed only in the area and common information that is distributed in the area and other areas, and the common information stored in the database. Is updated, the update information indicating the update content of the common information is notified to another regional database management system via the communication line, and updated from the other regional database management system via the communication line. When the information is received, the information exchanger who updates the common information in the database according to the update information A wide area database management system comprising steps. 3. The information exchange means of each regional database management system receives a common information update request from a client in the region, and when the common information is updated in response to the update request, the update is completed. The wide area database management system according to claim 2, wherein the information exchange means of the other area database management system is prohibited from accepting another update request for the common information until then.