JP2001142766A - Data base exchange system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data base exchange system by which the compatibility of each DB is secured when data are changed, etc., in a server DB and a client DB. SOLUTION: A computer system is constructed by providing a server computer 10 having a server and relation data base (server DB) connected to a network and a client computer 12 having a local and relation data base (local DB) being connection possible to the network and, then, data of the server DB and data of the local DB are exchanged in a data base exchange system. The data base exchange system is provided with means (synchronizing control part, etc.), 12 and 13 for executing control to permit non-coincidence between server DB data and local DB data to coincide with latest contents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database exchange system, and more particularly to a system using a relational database when data addition, change, deletion, etc. occur between a server database of a server and a local database of a client. The present invention also relates to a database exchange system that can ensure the consistency of each database quickly and accurately.

[0002]

2. Description of the Related Art Recently, so-called mobile users (mobile computers and portable computer users) who use PCs even outside offices have increased due to the spread of notebook PCs and the reduction in price of PCs. At that time, a form in which information in a database in an office is copied to a local database of a mobile client and the same application is used in a mobile environment as when connected to an in-house LAN has begun to appear.

[0003] The reasons for the increase in mobile computers are not only the high portability but also the data editing function, which is a conventional function, and the fact that information can be transmitted from a remote place via a network such as a public line. This is probably due to the ability to exchange.

There are the following three examples of the conventional system of the above-described embodiment. First conventional example: Japanese Unexamined Patent Publication No. 7-225709 The database updating system described in this publication relates to a database updating system between a master database system and a plurality of local database systems connected to the master database system. This is a database update system that can perform update.

Second conventional example: Japanese Patent Application Laid-Open No. H10-301828 The database management system described in this publication reduces the amount of information to be transmitted in order to maintain the consistency between the master database and the local database, and shortens the amount of information to be transmitted. It is a system that can perform transmission.

Third conventional example: Japanese Patent Laid-Open Publication No. H11-45201 The database management system described in this publication discloses a database management system which uses the same server resource to update data generated by an access conflict when a plurality of client computers try to update the same server resource. To provide a computer system suitable for realizing a network computer for mobile use so as to avoid inconsistency.

[0007]

However, the first conventional example (JP-A-7-225709) has the following problems. That is, the local database system is read-only and cannot be changed. The reason for this is
This is because the local system only considers data reference.

The second conventional example (Japanese Patent Application Laid-Open No. 10-301828) has the following problem. That is, when the number of data items increases, not only does the storage capacity of the database be wastefully squeezed, but also the search performance of the monitoring information table decreases, resulting in a decrease in overall performance.

The reason for this is that, in order to ensure consistency, the server or client information updated for all information stored in the server database and the local database and the update time must be stored in the monitoring information table. Because it does not become.

The third conventional example (Japanese Patent Laid-Open No. 11-45201) has the following problem. That is, when a server resource is accessed from a certain client, there is a possibility that only reading can be performed. The reason for this is that locking is performed at the time of downloading resources in resource units in order to ensure consistency, thereby preventing changes by other client users.

Accordingly, an object of the present invention is to provide a system using a relational database, in which, even when data is added, changed, deleted, or the like in a server's master database and a client's local database, the consistency of each database is maintained. An object of the present invention is to provide a database exchange system that can be secured quickly and accurately.

[0012]

According to the present invention, there is provided a server computer having a server database connected to a network, and a client computer having a local database connectable to the network. In a database exchange system in which a computer system is constructed to exchange data of the server database with data of the local database, the server database and the local database are relational databases.

Further, the database exchange system includes:
The database exchange system, when there is a mismatch between the data of the server database and the data of the local database, the exchange control to match the data of the server database and the local database to the latest content And a coincidence exchange control means for performing the operation.

[0014] According to this configuration, even when a data mismatch between the master database (server database) of the server and the local database of the client occurs due to addition, change, deletion, etc. of the data, the operation of the coincidence exchange control means respectively. The database consistency can be ensured at high speed and accurately.

Further, the matching exchange control means is provided with a synchronization rule which can be operated from any of a server computer and a connectable client computer.

In this way, the consistency of the database can be ensured from both the server computer and the connectable client computer (ie, mobile computer).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a database exchange system according to the present invention will be described based on the illustrated embodiment.

[I] Concept of the Present Invention First, the concept of the present invention will be described with reference to the database exchange system DK of the embodiment of the present invention shown in FIG. The present invention provides a system that uses a relational database to quickly and accurately ensure the consistency of each database even when data is added, changed, or deleted in the master database of the server and the local database of the client. It is intended to provide a configuration which can be performed.

In FIG. 1, there are a server database 11 in a server computer 10 and a local database 21 to which difference data required for a mobile client computer 20 has been downloaded. The information in the server database 11 is directly operated on data in the database by the client computer 30 having no local database, and the local database 21 is directly operated by the mobile client computer 20 having the local database. The server database 11 and the local database 21 are independent,
Data manipulation is possible individually.

The operation of matching the contents of the server database 11 and the contents of the local database 21 is called "synchronization".
By performing this synchronization, the changed contents of the server database 11 are reflected on the local database 21 and the changed contents of the local database 21 are reflected on the server database 11, so that consistency between the databases can be maintained. With this mechanism, the mobile client computer 20 does not need to be constantly connected to the network, and the synchronization between the server database 11 and the local client 31 can be maintained by performing a synchronization operation when necessary.

The minimum unit at the time of synchronization is a line unit, and the data transmitted between the server computer 10 and the mobile computer 12 is the minimum information of only the changed part, thereby enabling the synchronization processing. Such time can be saved.

[II] Description of Embodiment (1) Configuration of Embodiment FIG. 1 is a system configuration diagram of a database exchange system DK of this embodiment. Database exchange system DK
Is uniquely identified from the server computer 10 by the mobile client name (for example, the user's first and last names are registered in advance and used for identification).
The mobile client computer 20 which is a "connectable client computer" which is not always connected (can be connected as necessary) via the network 40 such as a public network, and the server computer 10
N or the like, and a client computer 30 which is an “always-connected client computer” which is always connected via a network 45.

The server computer 10 includes a server database 11 composed of a relational database, a synchronization control unit 12 which is a "coincidence exchange control means" operated by program control, and a data operation confirmation unit 13.
The server database 11 includes a change request pool table 11a and a change information table 11b described below.

Mobile client computer 20
Includes a local database 21 composed of a relational database, a synchronization control unit 22 that is a "match exchange control unit", and a data operation confirmation unit 23. The local database 21 includes a change request pool table 21a and a change information table 21b described below. The mobile client computer 20 is a LAN or W
It is connected to the server computer 10 via the AN, the public network, or the Internet.

The client computer 30 comprises a desktop personal computer or the like installed in an office, and is always connected to the server computer 10 via a LAN.

(2) Operation of Embodiment (2-1) Schematic Operation First, the schematic operation of this embodiment will be described with reference to the schematic operation flowchart shown in FIG. 2, and then the detailed operation will be described with reference to FIGS. Will be described.

As shown in FIG. 2, first, the local database 21 of the mobile client computer 20
Then, the data of the server database 11 is downloaded (step S1). Once this operation is performed, there is basically no need to perform it again. This work is called “initial synchronization”.

Here, as shown in FIGS. 13A and 13B, the data in the server database 11 is organized in units of "rows" specific to the relational (relational) database. A plurality of mobile clients are associated with each other, and this information is managed in the server database 11. Each row has a unique data item (Row ID) that identifies it.

When the initial synchronization is performed, the row data (FIG. 13) related to the mobile client that has performed the initial synchronization is displayed.
(A)) is downloaded, and unrelated line data is not downloaded. With this mechanism, it is possible to minimize the capacity of the local database. In other words, the claim corresponds to "a minimum unit of data when exchange control is performed by the coincidence exchange control means is a line unit of the relational database in the server database and the local database".

If there is a change, addition, or deletion (referred to as a change, etc.) of the database after the above-described initial synchronization (step S2), the change from the client computer 30 or the change from the mobile client 20, etc. The processing is different depending on the situation.

In the case of a change from the client computer 30 or the like, the processing shown in FIG. 3 is performed, and the characteristic processing of this processing is a change in the version information (step S3).
a). Here, the version information is one of the data items included in each row, and is an item that is simultaneously changed when data is updated on the server database 11 side (FIG. 1).
3 (A), right end). Mobile client 2
In the case of a change from 0, the processing shown in FIG. 4 is performed (step S3b).

By the operation from the client computer 30 and the mobile client 20, the server database 11 and the local database 21
Inconsistency (mismatch) may occur in registration information. It is necessary to synchronize the server database 11 and the local database 21 in order to achieve consistency. A request for synchronization is made from the mobile client computer 20 to the server computer 10 (step S4).

The processing of the synchronization request is divided into processing of a request from the mobile client 20 (step S5a), processing on the server computer 10 side (step S5b), and processing on the mobile client 20 side (step S5c).

Mobile client 2 in step S5a
After completion of the processing of the synchronization request from 0, the mobile client 20 is disconnected from the network (step S6).
A characteristic of the processing on the server computer 10 side in step S5b is to avoid collision by a synchronization rule when version information described later does not match.

Mobile client 2 in step S5c
A characteristic of the process on the 0 side is avoiding collision by a synchronization rule accompanying confirmation of whether or not there is a row having the same unique item in a change information table 21b described later.

The above steps S1 to S5a, 5
By performing the processes b and 5c, even when data is added, changed, or deleted in the master database and the local database, the consistency of each database can be maintained.
It can be secured at high speed and accurately.

(2-2) Detailed Operation The detailed operation (actual database operation and the accompanying operation) of this embodiment will be described in detail with reference to FIGS.

As shown in FIG. 3, the client computer 30 changes the data to the data in the server database 11,
When addition or deletion is added, the operation is reflected in the server database 11 by monitoring of the data operation confirming unit 13, and the content of the operated line is written in the change information table 11b in one line (steps A1 and A2 in FIG. 3). , A3, A4). At that time, the above-mentioned version information is changed for the line.

The data format in the change information table 11b is as shown in FIG. When writing to the change information table 11b, one row of data is created for each mobile client associated with the data, and the data of the row is linked to the item “mobile client name” in FIG. The associated (corresponding) mobile client name is written. If the row is linked to multiple mobile clients, change information table 1
Multiple records are created in 1b.

As shown in FIG. 4, when data is changed, added, or deleted from the mobile client computer 20 to the local database 21, the data operation confirmation unit 2
3, the operation is reflected in the local database 21 and the content of the operated line is written into the change information table 21b as one line (steps A11, A12, and A12 in FIG. 4).
A13, A14). The data format in the change information table 21b is as shown in FIG.

Due to these operations, inconsistency (mismatch) in registered information may occur between the server database 11 and the local database 21 as described above. The request for synchronization is sent from the mobile client computer 20 to the server computer 10 for the purpose of matching. This synchronization request will be described in the following three cases (-).

Mobile client computer 20
The processing when a synchronization request is made in is as follows.
As shown in FIG. 5, the synchronization control unit 22 first checks whether or not there is information in the change information table 21b (step A21 in FIG. 5). If the information exists, data transmission is performed after connection to the network, and the information in the change information table 21b is copied to the change request pool table 11a in the server database 11 in the server computer 10 (Step A23 in FIG. 5, A24, A25). The data format in the change request pool table 11a is as shown in FIG. However, if there is no information in the change information table 21b, the process proceeds to the check of the change information table on the server computer 10 immediately after the network connection is made (step A30 in FIG. 5).

Next, the synchronization control unit 12 of the server computer 10 checks whether or not there is change information for the synchronized mobile client in the change information table 11b in the server database 11. If there is change information, store it in the local database.
1 to the change request pool table 21a (FIG. 5).
Steps A27 and A28). Change request pool table 21
The data format in a is as shown in FIG. If there is no change information, the process proceeds to the next step (step A27 in FIG. 5).

After these processes are completed, the network is disconnected (step A29 in FIG. 5). The data is reflected in the server database 11 and the local database 21 based on the information of the received change request pool table.

The processing on the server computer 10 side is as follows. The synchronization control unit 12 checks the contents of the change request pool table 11a (Step A31 in FIG. 6).
If the information does not exist, the process ends (step in FIG. 6).
A32).

If the information exists, the first line of the information is checked. If the information is information to add a new line, the change is reflected in the server database 11, and then the contents of the change request pool table 11a are checked again. go. At this time, the data version of the newly added row is automatically input (steps A33 and A36 in FIG. 6).

If it is not a new line addition, the version information of the line having the same unique item in the server database 11 is confirmed based on the unique item of the changed line before reflecting the data change. If the version information matches, the change is reflected in the server database 11. When the change is reflected, the version information is updated (steps A34, A35, A36 in FIG. 6). If the version information does not match, a collision is avoided by a synchronization rule described below (step A37).
Change request pool table 11 of server computer 10
The corresponding information in a is cleared (step A38), and after these processes, the contents of the change request pool table 11a are checked again. If there is no information, the process ends (step A32 in FIG. 6).

Thus, the server computer 10
If there is a change in the server database 11, the change request information for mobile clients other than the mobile client that executed the change is described in the change information table.

The processing on the mobile client 20 side is as follows. The synchronization control unit 22 checks the contents of the change request pool table 21a (step A4 in FIG. 7).
1). If there is no information, the process ends (step A42 in FIG. 7). If the information exists, the information is checked. If the information is a new line, the change is reflected in the client database (local database) 21 and the contents of the change request pool table 21a are checked again.

If the row is not a new row, it is checked before the data change is reflected whether there is a row having the same unique item in the change information table 21b based on the unique item of the changed row. Do. Thus, it is determined whether or not a collision has occurred. If it is determined that no collision has occurred, the change is reflected in the client database 31 (steps A44, A45, A46). If it is determined that a collision has occurred, the collision is avoided according to a synchronization rule described below (step A47). After these processes,
The content of the change request pool table 21a is checked again.
If the information does not exist, the process ends (step in FIG. 7).
A42).

The avoidance of collision by the synchronization rule will be described. In the synchronization rule, setting of server priority and client priority is performed. The priority setting serves as a criterion for determining which data has priority in the event of a collision, and it is necessary that the contents set between the server computer 10 and all the mobile computers 12 match. These processes are performed by the server computer 10 or the mobile computer 12.
Is performed by the synchronization control unit 12 or the synchronization control unit 22.

If the server computer 10 gives priority to the server, the change is not reflected in the server database 11 (step A51 in FIG. 8). If the server computer 10 gives priority to the client, the change is made to the server database 1
1 (step A61 in FIG. 9).

When the mobile client computer 20 gives priority to the server, the change is reflected in the local database 21 (step A71 in FIG. 10).

If the mobile client computer 20 gives priority to the client, the change is not reflected in the local database 21 (step A81 in FIG. 11).

[III] Next, the operation of this embodiment will be described using a specific example. When the data of the server database 11 is changed from the client computer 30 (step S10), the change is detected by the data operation check unit 13 (step S11), and the change is described in the change information table 11b (step S12). . Similarly, when the data of the local database 21 is changed from the mobile client computer 20 (Step S10),
The change is detected by the data operation confirmation unit 23 (step S
11), the contents of the change are described in the change information table 11b (step S12).

When a synchronization request is made by the mobile client computer 20 (step S13), the synchronization control unit 2
2 confirms that there is information in the change information table 21b (step S14), and copies the data to the change request pool table 11a of the server computer (step S14).
15). Further, the synchronization control unit 1 of the server computer 10
2 confirms that there is information in the change information table 11b (step S16), and copies the data to the change request pool table 21a of the mobile client computer 20 (step S17).

After confirming that there is information in the change information table 21b, the synchronization control unit 22 reflects the information in the local database 21 (step S18).

Thus, even when data is added, changed, or deleted in the master database of the server and the local database of the client, the consistency of each database can be ensured at high speed and accurately. Can be.

[0059]

As described above, according to the present invention, the following effects can be obtained. The first effect is that a database can be quickly accessed in a mobile environment that is not always connected. The reason is that the mobile client has a local database.

The second effect is that it is possible to maintain consistency between the server database in the server computer and the local database in the mobile client in a mobile environment that is not always connected. The reason is that the information exchange of the changed part of the server database and the local database can be performed by the synchronization processing performed from the mobile client, and the contents of the database can be updated based on the information.

The third effect is that data, rows can be added, changed, and deleted from both the server database and the mobile database (a specific example of the second effect), and further consistency can be maintained. It is in. The reason is that a rule at the time of data operation collision is defined in the synchronous processing.

The fourth effect is that the synchronization processing can be executed in a short time, so that the time for connecting to the network can be reduced. The reason is that only the changed information is transmitted instead of the information of the entire database.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of a schematic operation of the embodiment.

FIG. 3 is a flowchart of a data operation of a client computer in the embodiment.

FIG. 4 is a flowchart of data operation of a local database of the mobile client in the embodiment.

FIG. 5 is a flowchart of a synchronization request of the mobile client in the embodiment.

FIG. 6 is a flowchart on the synchronization reflection process server side in the embodiment.

FIG. 7 is a flowchart of a synchronous reflection process local side in the embodiment.

FIG. 8 is a flowchart of the server computer in the embodiment, with server priority.

FIG. 9 is a flowchart of a client priority on the server computer side in the embodiment.

FIG. 10 is a flowchart of server priority on the mobile client side in the embodiment.

FIG. 11 is a flowchart of client priority on the mobile client side in the embodiment.

FIG. 12 is an operation flowchart of a specific example in the embodiment.

FIG. 13 is a diagram showing the information content of a database row and the configuration of a relational database in the embodiment.

FIG. 14 is a diagram showing another information content of a row of the database in the embodiment.

FIG. 15 is a diagram showing another information content of a row of the database in the embodiment.

[Explanation of symbols]

 DK database exchange system 10 server computer 11 server database 11a change request pool table 11b change information table 12 synchronization control unit 13 data operation check unit 20 mobile client computer 21 local database 21a change request pool table 21b change information table 22 synchronization control unit 23 data Operation confirmation unit 30 Client computer 40 Network 45 LAN

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06F 15/401 340A

Claims (5)

[Claims] 1. A computer system comprising a server computer having a server database connected to a network, and a client computer having a local database connectable to the network, wherein data of the server database and the local data are stored. In a database exchange system capable of exchanging data with a database, the server database and the local database are relational databases. 2. The database exchange system according to claim 1, wherein when there is a mismatch between the data in the server database and the data in the local database, the data in the server database and the data in the local database are updated to the latest contents. 2. The database exchange system according to claim 1, further comprising a coincidence exchange control means for performing exchange control for causing coincidence. 3. The database exchange system according to claim 2, wherein said matching exchange control means includes a synchronization rule which can be operated from any of a server computer and a connectable client computer. 4. The database exchange system according to claim 2, wherein the cause of the mismatch is at least one of addition, change, and deletion to the database. 5. The data processing system according to claim 1, wherein a minimum unit of data when the exchange control is performed by the coincident exchange control unit is a line unit of a relational database in the server database and the local database. A database exchange system according to any of the above.