JPH0552537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] This is a database system having database management modes of public mode and personal mode, and a transaction management method for mixedly using the database accesses of both modes. At the end of a transaction, which is the unit of management of access to a public mode database, synchronizing the exclusive end processing of the personal mode database that was accessed during the transaction allows database management when both modes of databases are used together. It is possible to guarantee consistency between

[Industrial application field]

The present invention relates to a database system in a computer system having database management modes of public mode and personal mode, and to a transaction management method for mixedly using database accesses of both modes.

Generally, some databases are shared by a wide range of users, while others are intended for limited use only.

For databases belonging to the former category, system-level access management that takes into account content preservation and access efficiency needs to be fully supported. For this reason, when accessing, it is necessary to prepare various control information defined by the system, and the overhead for management tends to be large.

Regarding the latter, ease of use and efficiency can be improved by leaving such management to the user.

For this reason, as is well known, database systems have two management modes: the former, which is a shared database that is shared on a system scale, and the latter, which is a public mode that is used for the work of individuals or small groups. A personal mode is provided for databases that are created and used locally, and for public mode databases, advanced management is provided that emphasizes content preservation during access and allows for efficient use by a large number of people. is provided as a system management function, and with respect to the personal mode database, management such as content preservation is left mostly free to application programs, etc., so that appropriate measures can be efficiently taken according to the needs of each business.

[Problems to be solved by conventional technology and invention]

FIG. 2 is a block diagram showing an example of the configuration of a computer system having a database system.

The database system 2 executed by the processing device 1 is a system for controlling access to the database 4, and is controlled by a known method such as execution of a database access macro instruction in an appropriately started application program 3. It supports the application program 3's database access and returns the results to the request source.

Here, when the application program 3 uses the database managed in the public mode, it accesses it via the transaction management section 5.

For this purpose, the application program 3 creates control information with a predetermined system configuration in advance, registers it in the database 4, and instructs the transaction management unit 5 to start a transaction using the specification information 6 that specifies the control information as a parameter. request. This control information includes information about specifying the target database,
and the specification of external log files.

In transaction start/end processing 8, transaction management section 5 uses the support functions of database access control section 7 to perform processing such as exclusive control by occupying a required area of a specified database.

Furthermore, in accessing the database, in access processing 9, logs are collected to maintain the updated database.

When this transaction is requested to end,
The transaction start/end processing 8 enables updates/additions/deletions, etc. to the database by processing during the transaction, and
By releasing the possession, other access is possible.

Here, if multiple databases are specified to be handled during a transaction, for example, if there is a first process that requires updating two databases, the first process will update one database. However, if you allow another second process to refer to both databases while the other one has not been updated, there is a possibility that the second process will use inconsistent content between the two databases. Therefore, it is necessary to synchronize the processes such as releasing the exclusive use of these databases, and to control such that there is no inconsistency in the subsequent use of the databases due to inconsistencies in the contents between the databases.

Furthermore, when a transaction cancellation request is made, the transaction cancellation processing 10 invalidates updates/additions/deletions to the database during the transaction and restores the previous database using a log file or the like. .

When the application program 11 that uses a database managed in the personal mode accesses the database, the application program 11 directly uses the support function of the database access control unit 7 to access the required database. The trigger for setting/cancelling exclusive control, collection of logs, etc. are left to the application program 11.

In this way, because the system support for public mode databases and personal mode databases is different, even when a single application program accesses databases in both modes, the access termination process is different between databases in both modes. As a result, the following situations may occur, for example:

That is, for example, using a personal mode database S and a public mode database B related to S, update data a in B according to the input data, and then update data a' in S to data a. Assume that there is a task in which the processing of updating data b of B in accordance with the next input data and updating data b' of S in accordance with data b is performed in one transaction.

If the above is completed normally, there will be no problem, but if some abnormal event occurs when updating database B, database B in public mode will be updated during the transaction (i.e., Although the original content is guaranteed by invalidating the update), the update in the database S in the personal mode remains completed, and consistency in terms of actual content with the database B cannot be maintained.

Therefore, considering this situation, there has been a problem that databases of both modes cannot generally be used together.

[Means for solving problems]

FIG. 1 is a block diagram showing the configuration of the present invention.

26 is a database system of the present invention,
The transaction management unit 20 is provided with a personal mode transaction end process 21 and a personal mode transaction cancel process 22, in contrast to the conventional transaction start/end process 8 and transaction cancel process 10.
At the end of the transaction, a determination process 23 or 24 determines which process is to be executed.

[Effect]

When control is passed from the application program 25 due to a transaction termination request, the determination processing 23 determines whether there is a personal mode database accessed during the transaction, and if so, terminates the personal mode transaction. Through process 21, for the corresponding database,
In accordance with the transaction end process, validation of updates, release of exclusive occupancy, etc. are executed, and then the transaction start/end process 8 executes the end process of the database in public mode.

For transaction cancellation, personal mode database processing similar to the above-mentioned termination processing is executed through the determination processing 24.

It is assumed that the personal mode database to be accessed during a transaction is specified by the control information specified by the specification information 6, for example.

With the above configuration, it is possible to synchronize the transaction termination process when a public mode database and a personal mode database are used together. Also, as mentioned in the conventional explanation, there is a distinction between public mode and personal mode as management modes.
When processing is performed using only the personal mode database without using the public mode database, access can be performed with less management overhead as in the past.

〔Example〕

In FIG. 1, the application program 25 includes, in the control information specified by the specification information 6, a specification of a personal mode database to be accessed, in addition to various information regarding the public mode database as in the past. .

At the start of a transaction, the transaction start/end processing 8 performs transaction start processing for the database in public mode, as in the prior art.

The application program 25 directly uses the support of the database access control section 7 to control the database in the personal mode, as in the past.

When control is passed to the transaction management unit 20 in response to a transaction end request, the determination processing 23 determines whether there is a personal mode database accessed during the transaction,
If so, personal mode transaction end processing 21 is executed.

Personal mode transaction end processing 21 executes validation of updates and release of exclusive possession, etc. for the corresponding database in accordance with transaction end processing, and then transaction start/end processing 8 executes public release. Execute the termination process of the database in tsuku mode.

Similarly, for transaction cancellation requests,
If it is determined in the determination process 24 that processing of the personal mode database is required, the personal mode transaction cancellation process 22 invalidates the personal mode database update, etc., and then the transaction cancellation process 10 performs the following steps:
Process databases in public mode as before.

With the above configuration, it is possible to synchronize the transaction termination process when a public mode database and a personal mode database are used together.

In addition, in the case of an application program that performs processing using only the personal mode database,
As shown in the application program 11, by directly utilizing the support functions of the database access control unit 7 as in the past, access can be achieved with less management overhead.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a computer system having databases in public mode and personal mode, processing that mixes the databases in both modes can be used, thereby improving the usability of the database. This has a significant industrial effect.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention;
The figure is a block diagram of an example of a conventional configuration. In the figure, 1 is a processing device, 2 and 26 are database systems, 3, 11, and 25 are application programs, 4 is a database, 5 and 20 are transaction management units, 6 is specification information, 7 is a database access control unit, and 8 9 indicates transaction start/end processing, 9 indicates access processing, 10 indicates transaction cancellation processing, 21 indicates personal mode transaction termination processing, 22 indicates personal mode transaction cancellation processing, and 23 and 24 indicate determination processing.

Claims (1)

[Claims] 1. A transaction management unit executes predetermined transaction management, and the transaction management performs database occupancy control on a transaction-by-transaction basis, and controls the database during the transaction. This is a process that validates the update process that has been performed at the end of the transaction, and allows access to the public mode database that must be accessed through the transaction management unit and without going through the transaction management unit. In a computer system having a database that is managed separately from a personal mode database that can be accessed, both the public mode database and the personal mode database are accessed during the transaction. In this case, the transaction management unit is configured to execute transaction management for the personal mode database as well as the public mode database.