JPH10320256A - Data update control method and device for distributed database system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve work efficiency for updating data in a master database by updating data in a sub database based on update information held in an update history file when there is a reference request to the sub database. SOLUTION: When there is a reference request 12 from a host device or an operator to a sub database control part 10 concerning specified data among data held in a sub database 7, a sub data base managing part 6, which accepts the reference request 12, inquires whether a master database 2 is updated or not and sends an update information request 18 to a transmission/reception managing part 8. Then, it is confirmed from that transmission/reception managing part 8 based on update information 17 that two sets of data in the master data base 2 are updated, and relevant data among data held in the sub database 7 are updated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed system in which a department for inputting data and a department for using the data are different from each other. In a distributed database system that has a sub-database for each department that holds only the data required by the department that uses the data, the distribution status for matching the update status of the master database with the update status of the sub-database The present invention relates to a data update control method and apparatus for a database system.

[0002]

2. Description of the Related Art In a distributed system in which a department that inputs data and a department that uses the data are different, in addition to a master database that performs centralized management of data, among data managed by the master database, In a conventional distributed database system having a sub-database that holds only data required by a department that uses data for each department, in order to ensure consistency (coincide) data in the master database with data in the sub-database,
When updating the master database, the sub database is also updated at the same time.

FIG. 2 is a block diagram showing an example of a data update control device of such a conventional distributed database system.

[0004] In FIG. 2, a master database control unit 29 includes a master database 22, a master database management unit 21, and a transmission / reception management unit 25. The sub-database control unit 30 includes a sub-database 27, a sub-database management unit 26, and a transmission / reception management unit 28. The number of sub-database control units 30 is not limited to one, and a plurality of sub-database control units may be provided.

[0005] The master database management unit 21 of the master database control unit 29, when receiving a data update request 32 from the outside (upper device), the master database 22
Is updated, and the updated data 35 is sent to the transmission / reception management unit 25 at the same time. Transmission / reception management unit 25
Is a sub-database control unit 3 that holds the received update data in the sub-database 27.
0 to the transmission / reception management unit 28. The transmission / reception management unit 28 of the sub-database control unit 30 that has received the update data sends the update data 37 to the sub-database management unit 26 of the sub-database control unit 30 to which it belongs, and the sub-database management unit 26 The corresponding data in the corresponding sub database 27 is updated. When the data update of the sub database 27 is completed, the sub database management unit 26 sends an update completion notification 38 to the corresponding transmission / reception management unit 28. The transmission / reception management unit 28 that has received the update end notification 38 sends it to the transmission / reception management unit 25 of the master database control unit 29. The transmission / reception management unit 25
As a result, the update end notification 34 is sent to the master database management unit 21, and the master database management unit 21 performs an update operation of the next one data item.

[0006]

The conventional data update control means of the distributed database system as described above performs the update of the master database and the update of the sub-database at the same time. There is a problem that a waiting time occurs until the data update of the database is completed, and the work efficiency of the data update of the master database is reduced. Further, when a failure occurs on the sub database side, the data of the sub database cannot be updated, so that the data of the master database cannot be updated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the conventional data update control means of a distributed database system, improve the work efficiency of updating the data in the master database, and cause a failure in the sub database. Even in such a case, an object of the present invention is to provide a data update control means for a distributed database system which does not hinder data update of a master database.

[0008]

According to the present invention, an update history file is provided on the master database side, and when data in the master database is updated, update information including the update data is stored in the update history file. The data of the sub-database is updated by updating the data of the sub-database based on the update information held in the update history file when a reference request is issued to the sub-database. This is to achieve the purpose.

That is, in the data update control method for a distributed database system according to the present invention, a master database holding a large number of data for centralized management, and a part of the data held by the master database are held. A data update control method for a distributed database system having at least one sub-database, wherein update information when the master database is updated is stored in an update history file, and any one of the at least one sub-database is stored. When a reference request is issued to one of the sub-databases, the data of the master database is updated by updating the data of the sub-data base requested by the update information held in the update history file. To match the data in the database. It is obtained by the, in particular, is obtained by a number of sub-databases and multiple.

A data update control device for a distributed database system according to the present invention includes a master database for holding a large number of data for centralized management, and a master database management unit for updating the master database when an external update request is received. An update history file that holds update information including update data when the master database is updated, and the update history file that receives the update data from the master database management unit and includes the update data. An update history management unit that updates, adds, or deletes update information of the update history file and reads the update information from the update history file, and issues an update information request to the update history management unit. The update history management unit reads from the update history file. A first transmission / reception management unit for inputting the updated information and sending the updated information to the outside; at least one sub-database for holding a part of data held by the master database; A second transmission / reception management unit corresponding to each of the at least one sub-database for inputting the update information from a management unit, and an update information request to the second transmission / reception management unit when there is a reference request from outside. And a sub-database management unit corresponding to each of the at least one sub-database that receives the update information input by the second transmission / reception management unit and updates the sub-database, In particular, the number of sub-databases is plural.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a data update control apparatus for a distributed database according to the present invention.

In FIG. 1, a master database control unit 9 includes a master database 2, a master database management unit 1, an update history file 4, and an update history management unit 3.
And a transmission / reception management unit 5. The sub-database control unit 10 includes a sub-database 7, a sub-database management unit 6, and a transmission / reception management unit 8, and has a configuration similar to that of the sub-database control unit 10 in FIG. The number of the sub-database control units 10 is not limited to one and may be plural.

The master database management unit 1 of the master database control unit 9 updates the corresponding data in the master database 2 and updates the update data 13 when there is a data update request 12 from the outside (upper device). This is sent to the history management unit 3. When there are a plurality of pieces of update data, the master database 2 is sequentially updated one by one, and each time the update is completed, the update data is sent to the update history management unit 3.

The master database 2 holds a large amount of data for centralized management, and when receiving update data from the master database management unit 1, replaces the received update data with the corresponding old data. If the update data is new data, the data is newly written and held.

The update history management section 3 sends update information obtained by adding management information to the update data 13 sent from the master database management section 1 to the update history file 4. Also,
The update information is read from the update history file 4 and sent to the transmission / reception management unit 5. The management information to be added includes an update index indicating whether the update data is change data, additional data, or erasure data, a position designation index indicating the location of the update data, and an update date indicating the update execution date. And a sub-database designation indicating a sub-database holding the update data.

The update history file 4 stores the update history management unit 3
Holds the update information sent from. If the update data of the update information sent from the update history management unit 3 is update data for data already held, the update data is replaced with old update information holding the sent new update information.

The transmission / reception management unit 5 stores the update information received from the update history management unit 3 in the sub-database control unit 10 that holds data corresponding to the update data included in the update information in the sub-database 7. Transmission / reception management unit 8
Send to The information sent from the transmission / reception management unit 8 of the sub database control unit 10 is sent to the update history management unit 3.

The transmission / reception management unit 8 of the sub database control unit 10 is the transmission / reception management unit 5 of the master database control unit 9.
Sends the update information sent from the sub-database management unit 6 of the sub-database control unit 10 to which it belongs,
The information sent from the sub database management unit 6 is sent to the transmission / reception management unit 5 of the master database control unit 9.

When receiving the update information from the transmission / reception management unit 5, the sub-database management unit 6 determines from the management information included in the update information whether the data matches (is synchronized with) the data of the master database 2. If the data does not match (is not synchronized), the corresponding data in the corresponding sub-database 7 is updated. When there is a reference request 16 from outside, the sub database 7 is searched and returned to the request source.

The sub-database 7 holds a part of the data held by the master database 2 and updates the instructed data when instructed by the sub-database management unit 6. .

Next, the operation of the distributed database data update control device configured as described above will be described.

When an upper device or an operator issues an update request 12 to specific data in the data stored in the master database 2 to the master database controller 9, the master database manager 1 sends the update request 12 The corresponding data in the master database 2 is updated by the included update data, and the update data 13 is sent to the update history management unit 3. Update history management unit 3
Creates update information by adding management information such as an update index and a position designation index to the update data sent from the master database management unit 1, and sends it to the update history file 4.
When the update information is sent from the update history management unit 3, if the data included in the update information is data that changes data already held, the update history file 4 updates the received update information. Update by replacing data with old data. If the data included in the update information is new data to be added to the data already held, the data is added and held. If the update information is information for erasing the data already held, the storage of the designated data is erased and erased.

Further, when the second update request 12 is issued to the master database controller 9, the master database controller 9 repeats the above operation. Therefore, two pieces of update information are accumulated in the update history file 4.

In this state, when there is a reference request 16 for specific data in the data held in the sub-database 7 from the host device or the operator to the sub-database control unit 10, the sub-database receiving the reference request 16 The management unit 6 inquires whether or not the master database 2 has been updated, and if updated, sends an update information request 18 to the transmission / reception management unit 8 in order to obtain update information. The transmission / reception management unit 8 receiving the update information request 18 sends it to the transmission / reception management unit 5 of the master database control unit 9. The transmission / reception management unit 5 sends the update information request 14 to the update history management unit 3 in response to the update information request 14, and the update history management unit 3 that has input the update information request 14 updates the update history stored in the update history file 4 at that time. The information is read and sent to the transmission / reception management unit 5 as update information 15. The transmission / reception management unit 5 that has received the update information 15 sends the update information 15 to the transmission / reception management unit 8 of the sub-database control unit 10, and the transmission / reception management unit 8 transmits the update information 17 to the sub-database management unit 6. The sub-database management unit 6 knows from the update information 17 that two data items in the master database 2 have been updated, updates the corresponding data in the data stored in the sub-database 7, and then refers to the updated data. The data requested by the request 16 is read from the sub database 7 and returned.

For example, when there are ten sub-databases for one master database, and when an update request is made for one data of the master database, the conventional distributed database system requires a total of 11 sub-databases. It was necessary to update the database to make the data contents coincide (synchronize). However, when the synchronization control device of the distributed database is used, one master database and one update history file cannot be updated. Only two devices need to be updated. Therefore, the transmission time of the update data to the ten sub-databases is omitted, and the processing time in the master database control unit 9 is greatly reduced.

When there is a reference request to the first sub-database of the ten sub-databases, the sub-database control unit 10 having the first sub-database
Is the update history file 4 of the master database control unit 9.
, The data of its own sub-database is updated to the latest data, but at this point, the data of the second to tenth sub-databases has not been updated to the latest data. However, if there is a reference request to the second to tenth sub-databases, the data of each sub-database is updated to the latest data at that time, so at the time of the reference request, each sub-database becomes the master. This means that the data whose contents match the database (is synchronized) is retained.

If a failure occurs in one of the ten sub-databases, the conventional distributed database system cannot update the master database. When the control means is used, the master database can be updated irrespective of the state of the sub-database, and nine sub-databases other than the sub-database in which a failure has occurred can be referred to.

[0029]

As described above, according to the present invention, the update history file is provided on the master database side, and when the data of the master database is updated, the update information is stored in the update history file, Updating the data in the database is performed by updating the data in the sub database based on the update information held in the update history file when a reference request is made to the sub database. Since only two devices, one master database and one update history file, need to be updated at the time of updating,
There is an effect that the work efficiency of updating the data in the master database can be improved. Further, since the master database can be updated irrespective of the state of the sub-database, even if a failure occurs on the sub-database side, there is an effect that the data of the master database can be updated without any trouble.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a distributed database data update control device of the present invention.

FIG. 2 is a block diagram showing an example of a conventional distributed database data update control device.

[Explanation of symbols]

 1.21 Master database management section 2.22 Master database 3 Update history management section 4 Update history file 5.8.25.28 Transmission / reception management section 6.26 Subdatabase management section 7.27 Subdatabase 9.29 Master database control section 10.30 Sub-database control unit 12.32 Update request 13 Update data 14.18 Update information request 15.17 Update information 16 Reference request 35.37 Update data 34.38 Update end notification

Claims (6)

[Claims] 1. A distributed database system comprising: a master database holding a large number of data for centralized management; and at least one sub-database holding a part of data held by the master database. A data update control method, wherein update information when the master database is updated is held in an update history file, and a reference request is issued to any one of the at least one sub-database. A data update control method for a distributed database system, wherein data of the sub-database requested to be referred to is updated by the update information held in the update history file. 2. The data update control method for a distributed database system according to claim 1, wherein the number of sub-databases is plural. 3. A master database for holding a large number of data for centralized management, a master database management unit for updating the master database when there is an external update request, and update data for updating the master database An update history file holding update information including: updating the update information of the update history file by inputting the update data from the master database management unit and sending the update information including the update data to the update history file Or an update history management unit that performs addition or deletion and reads the update information from the update history file, and the update history management unit reads from the update history file by issuing an update information request to the update history management unit. A first transmission / reception management unit for inputting the updated information and transmitting the updated information to the outside; The at least one sub-database holding a part of the data held by the master database and the at least one sub-database receiving the update information from the first transmission / reception management unit. A corresponding second transmission / reception management unit, and receives an update information input to the second transmission / reception management unit by outputting an update information request to the second transmission / reception management unit when there is a reference request from outside. And a sub-database management unit corresponding to each of the at least one sub-database for updating the sub-database. 4. The data update control device for a distributed database system according to claim 3, wherein the number of sub-databases is plural. 5. A master database for holding a large number of data for centralized management, a master database management unit for updating the master database when there is an external update request, and update data for updating the master database An update history file holding update information including: updating the update information of the update history file by inputting the update data and transmitting the update information including the update data to the update history file; An update history management unit for reading the update information from the update history file; and inputting the update information read from the update history file by the update history management unit by issuing an update information request to the update history management unit. Master database control unit having a first transmission / reception management unit for transmitting to the outside A sub-database holding a part of the data held by the master database, a second transmission / reception management unit for inputting the update information from the first transmission / reception management unit, and a reference request from the outside. A sub-database management unit that outputs an update information request to the second transmission / reception management unit, receives the update information input by the second transmission / reception management unit, and updates the sub-database. A data update control device for a distributed database system, comprising: one sub-database control unit. 6. The data update control device for a distributed database system according to claim 5, wherein a plurality of sub-databases are provided.