JP2001134480A - System and method for file exclusive control and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the mismatching of file update in a file sharing. SOLUTION: A file reading part 21 reads records from a file, and exclusive counter reading part 22 reads the value of an exclusive counter from the read records. A previous counter storing part 31 stores the value of the exclusive counter transferred from the exclusive counter value transferred from the exclusive counter reading part 22 as the previous counter value. An exclusive counter reading part 41 reads the records read by the file reading part 21 from the file again, and reads the value of the exclusive counter of the read records. A counter reading and comparing part 42 reads the previous counter value through a counter reading part 32, and compares the counter value with the value of the exclusive counter read by the exclusive counter reading part 41. When the both counter values are matched with each other, a data updating part 51 updates the data, and a counter adding part 53 adds 1 to the value of the exclusive counter, and a file writing part 53 writes the records back in the file.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exclusive control method for a file, and more particularly to an exclusive control method, a method, and a recording medium for a system shared file in a client / server system.

[0002]

2. Description of the Related Art In a client / server system, when a system common asset such as a master file such as an index sequential file or a sequential file is shared, the system common asset is stored only in the server. The client terminal connected to the server can fetch, process, and write necessary data from the shared assets of the server when necessary.

[0005] On the other hand, when the shared assets of the system are not shared, each client terminal individually has the shared assets of the system, and it is necessary to hold a magnetic disk device for a master file and the like.

[0004] As described above, sharing the common assets of the system can reduce the cost of the entire system and has many advantages.

However, sharing a system shared file means that when one client terminal is processing a system shared file, another client terminal may process the same file. Means.

For this reason, there is known an exclusive control system for controlling a file to be inaccessible from another until the file is closed until the file is closed. In this method, opening the file later is rejected even if only the file is referenced.

[0007]

However, the above-mentioned prior art has the following problems.

The first problem is that when the exclusive control method is not adopted, for example, when the update processing of the record of the shared file is performed at the client terminal A, the update processing is performed on the same record from the client B terminal. If you do, A
The result of the client terminal update process is not inherited,
The B client terminal updates the old record contents and writes it back to the file. As a result, the result of the A client terminal update process is lost.

A second problem is that when the exclusive control method is adopted, for example, when the update processing of the record of the shared file is performed on the A client terminal, the reference processing for the same file is performed from the B client terminal. That is not possible.

An object of the present invention is to provide a file exclusion control method using a counter method which solves the problem of exclusive control of a shared file.

[0011]

According to a first aspect of the present invention, there is provided a file exclusion control method for storing an exclusion counter value for performing a record exclusion control of a file, and an exclusion counter for reading a record from a file. Means for writing back the record whose data has been updated to the file when the value is equal to the exclusive counter value used when updating the data of the record.

A file exclusion control method according to a second aspect of the present invention is a file exclusion control method for reading a record from a file and reading an exclusion counter value for the record, and using the exclusion counter value read by the file read processing means as a previous counter value. Storage means for storing as
Exclusive control means for re-reading the exclusive counter value for the record, comparing it with the previous counter value stored in the storage means, and transferring control to the file writing processing means when the values match, updating the data content of the record File write processing means for adding 1 to the exclusive counter value for the record and writing the record back to the file.

[0013] In a file exclusion control method according to a third invention of the present application, in the second invention, the exclusion counter exists in the record of the file.

According to a fourth aspect of the present invention, there is provided a file exclusive control method for storing an exclusive counter value for performing a record exclusive control of a file, reading a record from a file, reading an exclusive counter value for the record, and reading the exclusive counter value. Store the value as the previous counter value,
The exclusive counter value for the record is read again and compared with the previous counter value stored, and when the comparison is made, the data content of the record is updated, and 1 is added to the exclusive counter value for the record, and Write the record back to the file.

[0015] In a file exclusion control method according to a fifth invention of the present application, in the fourth invention, the exclusion counter value is stored in the record of the file.

According to a sixth aspect of the present invention, there is provided a storage medium for storing an exclusive counter value for performing a record exclusive control of a file, a file reading process for reading a record from a file and reading an exclusive counter value for the record. A storage process for storing the read exclusive counter value as a previous counter value, an exclusive control process for reading the exclusive counter value for the record again and comparing the read exclusive counter value with the previously stored counter value, and A program for updating a data content of the record, adding 1 to an exclusive counter value for the record and writing the record back to a file, and causing a computer to execute the file writing process. I do.

According to a seventh aspect of the present invention, in the recording medium according to the sixth aspect, a program for causing a computer to execute an exclusive counter value storing process of storing the exclusive counter value in the record of the file is recorded. Features.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a client / server system, if a file to be processed by a certain client is a shared file of the system, there is a possibility that another client will process the same file.

A feature of the file exclusion control method according to the present invention is that a means for determining whether or not the content of the file has been updated from another client during the update processing of the system shared file is provided. This is to have means for performing a subsequent file write-back process only when no update has occurred.

As a result, even if the contents of the file are updated from another client and the reference contents are changed, inconsistency in processing such that subsequent file write-back processing is performed can be prevented.

Embodiments of the present invention will be described in detail with reference to the drawings.

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

Referring to FIG. 1, according to the embodiment of the present invention, an input device 1, a file read processing device 2, a storage device 3, an exclusive control device 4, and a file write processing device 5
And an output device 6.

The input device 1 is a device for inputting a file reading command to the file reading processing device 2 and a command for updating the set value of the read file, such as a keyboard.

The file reading processing device 2 reads a record from the file specified by the input device 1, reads the value of the exclusive counter, and transfers the contents of the read record to the output device 6. The file reading processing device 2 includes a file reading unit 21 and an exclusive counter reading unit 22.

The file reading section 21 reads a record from a file. FIG. 2 shows the format of the record. Referring to FIG. 2, the record is composed of a data field for storing data of the record and an exclusive counter field for storing the value of the exclusive counter. In the example of FIG.
The exclusive counter field is at the end of the record, but may be at the beginning of the record.

The exclusive counter reading unit 22 reads the value of the exclusive counter from the record read by the file reading unit 21.

The storage device 3 stores the value of the exclusive counter as the previous counter value, and reads out the stored value of the previous counter. The storage device 3 includes a previous counter storage unit 3
1 and a counter reading unit 32.

The previous counter storage unit 31 stores the value of the exclusive counter passed from the exclusive counter reading unit 22 as the previous counter value.

The counter reading section 32 reads the value of the previous counter stored in the previous counter storage section 31.

The exclusive control device 4 reads the exclusive counter value of the record again, reads the previous counter value stored in the storage device 3, compares the two counter values, and if they match, sends the file write processing device 5. Transfer control. The exclusive control device 4 includes an exclusive counter reading unit 41 and a counter extraction comparing unit 42.

The exclusive counter reading unit 41 reads the record read by the file reading unit 21 again from the file and reads the value of the exclusive counter of the record read.

The counter extracting / comparing unit 42 reads the previous counter value from the previous counter storage unit 31 via the counter reading unit 32 and compares the read value with the value of the exclusive counter read by the exclusive counter reading unit 41. If so, the control is transferred to the file writing processor 5.

The file writing processor 5 updates the data of the record, adds 1 to the value of the exclusive counter, and writes the record back to the file. File writing processor 5
Includes a data updating unit 51, a counter adding unit 52, and a file writing unit 53.

The data updating section 51 updates data in a data field of a record.

The counter adding section 52 includes a data updating section 51
Adds 1 to the value of the exclusive counter field of the record whose data has been updated.

The file writing unit 53 includes a data updating unit 51
Then, the record processed by the counter adding unit 52 is written back to the file.

The output device 6 is a device for outputting the contents of the record read from the file by the file reading section 21, and is a display device, a printing device, or the like.

The operation of the embodiment of the present invention will be described in detail with reference to FIGS. 1, 2 and 3.

FIG. 3 is a diagram showing a flow of the operation of the embodiment of the present invention.

Referring to FIG. 3, according to a command input from the input device 1, the file reading unit 21 of the file reading processing device 2 reads a record of a file to be processed (step A1).

At this time, the exclusive counter reading section 22 reads the value of the exclusive counter of the record (step A2),
The data is stored in the previous counter storage unit 31 of the storage device 3 (step A3).

Thereafter, based on the contents of the read record, an output is made to the output device 6 such as a CRT screen (step A4).

In the case where the input from the input device 1 is processed into the contents displayed on the CRT screen or the like and is written into the same file again, the exclusive counter reading unit 41 of the exclusive control device 4 reads the exclusive counter value of the record. Read again (steps A5 to A6).

Thereafter, the counter extracting / comparing section 42 instructs the storage device 3, and the counter reading section 32 reads the previous counter value from the previous counter storing section 31 and passes it to the counter extracting / comparing section 42 (step A7).

The counter extracting / comparing section 42 compares the read exclusive counter value with the passed exclusive counter value (step A8).

When the exclusive counter values match as a result of the comparison, the exclusive control unit 4 instructs the file writing processing unit 5 to write the file. File writing processor 5
The data updating unit 51 updates the data of the record (step A9).

After the updating, the counter adding section 52 adds 1 to the exclusive counter (step A10).

The file writing section 53 writes back the updated record (step A11).

If the exclusive counter values do not match as a result of the comparison, the output device 6 is notified that updating is not possible, and processing such as screen display is performed (step A12).

In this way, despite the fact that the content of the file has been updated from another during the process of updating the file shared by the system in the client / server system and the reference content has changed, the subsequent file writing process Process can be prevented.

In the above embodiment, the exclusive counter for the record is provided in the record. However, the exclusive counter may be provided outside the record. For example, an exclusive control file may be provided, and an exclusive counter may be stored therein. In this case, if the exclusion counter is stored in the exclusion control file according to the storage order of the records in the file, it is possible to associate the record with the exclusion counter corresponding thereto.

In the above-described embodiment of the present invention, a program or the like for executing a processing operation of the file exclusion control method is recorded as data on a recording medium (not shown) such as a magnetic disk or an optical disk. It is used to read the recorded data and operate the file exclusion control method. As described above, the data for operating the file exclusion control method according to the present invention is recorded on a recording medium, and the function of the file exclusion control method can be realized by installing the recording medium.

[0054]

The first effect of the present invention is as follows.
The exclusion of a shared file in a server system can be performed. As a result, it is possible to prevent inconsistency in processing in which a shared file being updated in one client terminal is modified by another client terminal, and then a file write-back process is performed.

The reason is that a means is provided for determining whether or not the content of the file has been updated from another client terminal during the process of updating the system shared file, and the content of the file has not been updated. This is because a means for performing the subsequent file write-back processing is provided only in the case.

A second effect of the present invention resides in that even during an update process on a shared file in the client / server system, a reference process from another can be performed on the file.

The reason is that a means for determining whether or not the content of the file has been updated from another client terminal during the processing of the system shared file is provided.
This is because, when a process for the file from another client terminal is referred to, a means for performing a subsequent file write-back process is provided.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a record format.

FIG. 3 is a diagram showing a flow of operation according to the embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 input device 2 file reading processing device 3 storage device 4 exclusive control device 5 file writing processing device 6 output device 21 file reading unit 22 exclusive counter reading unit 31 previous counter storage unit 32 counter reading unit 41 exclusive counter reading unit 42 counter extraction Comparison unit 51 Data update unit 52 Counter addition unit 53 File writing unit

Claims (7)

[Claims] An exclusive counter for storing an exclusive counter value for performing record exclusive control of a file, an exclusive counter value for reading a record from a file, and an exclusive counter value for updating data of the record. Means for writing back the record whose data has been updated in the case of being equal to the file, to the file. 2. An exclusive counter for storing an exclusive counter value for performing a record exclusive control of a file, a file read processing means for reading a record from a file and reading an exclusive counter value for the record, and a file read processing means for reading the exclusive counter value for the record. Storage means for storing the exclusive counter value as a previous counter value, and file read processing means for reading the exclusive counter value for the record again, comparing with the previous counter value stored in the storage means, and matching the file. A file exclusion control method for updating the data content of the record, adding 1 to an exclusion counter value for the record, and writing the record back to a file. . 3. The file exclusion control method according to claim 2, wherein the exclusion counter exists in the record of the file. 4. An exclusive counter value for performing record exclusive control of a file is stored, a record is read from a file, an exclusive counter value for the record is read, and the read exclusive counter value is stored as a previous counter value. The exclusive counter value for the record is read again and compared with the previously stored counter value, and when the comparison is made, the data content of the record is updated, and 1 is added to the exclusive counter value for the record to obtain the record. File exclusive control method, wherein the file is written back to a file. 5. The method according to claim 4, wherein the exclusive counter value is stored in the record of the file. 6. A storage process for storing an exclusive counter value for performing record exclusive control of a file, a file reading process for reading a record from a file and reading an exclusive counter value for the record, and a process for storing the read exclusive counter value. A storage process for storing the previous counter value as a previous value, an exclusive control process for reading the exclusive counter value for the record again and comparing the value with the stored previous counter value, and updating the data content of the record when the comparison is made A recording medium on which a program for causing a computer to execute a file writing process of adding 1 to an exclusive counter value for the record and writing the record back to a file is recorded. 7. The recording medium according to claim 6, wherein a program for causing a computer to execute an exclusive counter value storage process for storing the exclusive counter value in the record of the file is recorded.