JP2001159993A - Method and device for storing data for referring to optional time state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem such that a database state at an optional time is not traced back and referred at the optional time and also a back-up generation time is required to be clearly indicated by a user in a conventional method for generating a back-up database to manage a generation, which is provided for referring to not only a present database state but also a past database state. SOLUTION: A data storage device is provided with a mechanism for preserving pre-updating information in a reference possible form concerning database updating and for managing the pre-updating information with preserved pre- updating information and updating time information as keys. Then the pre- updating information is specified by optional time designation and a past database state is restored and referred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database management system, and more particularly to a database management system capable of storing a history of addition, change, and deletion of data as referable data and reproducing a database state at an arbitrary time in the past. Storage method and apparatus.

[0002]

2. Description of the Related Art In the real world, since it is necessary to perform computer processing in accordance with human activities, there are many demands for storing database states on a daily or monthly basis and referencing them as necessary. In the case, JP-A-10-269126
In this method, a method of creating a backup of a database at a predetermined time, as in the method described in the above issue, is used, and the state of the database at the specific time is stored.

However, in this method, the user must always be aware of the time at which the database is to be backed up. Further, since the database must be acquired in multiples corresponding to the state of the database to be stored, many resources are required to store data.

[0004]

In the above-mentioned prior art, since the state of the database at the time specified by the user is stored, the data in the database may be changed between times when the state is stored. In the situation, there is a problem that the state of the database at an arbitrary time cannot be restored and referred to.

[0005] In addition, the conventional method has a problem that the user has to specify the time at which the state is to be saved, which imposes a burden on the user.

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to save the state of a database without requiring the user to be aware of the time at which the state is saved, and to modify the database state at an arbitrary time into the current database. Is to refer to without.

[0007]

In order to achieve the above object, in a system in which a database operation request from an application program such as addition, change, or deletion of data, or reference to a database content at a certain time, a database management system according to the present invention is provided. The system updates the database and acquires and stores the pre-update information of the data. The pre-update information of the data is classified for each key value of the database, and history management information for managing both the key and the update time information is created.

When the time is designated and the past state of the database is restored and referred to, the update time information of the pre-database update information storing the database contents at that time is specified from the history management information, and the key of the database is specified. Using the value and the time information, the corresponding pre-database update information is specified and selected.

As described above, by storing and managing the pre-update information of the database, the state of the database at an arbitrary time can be restored and referenced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, in order of system configuration and operation.

FIG. 1 is a schematic configuration diagram of a database management system capable of restoring a state at an arbitrary time and referencing it.
Elements related to the present invention include a database management system 100, a database 101, a history storage unit 102, and an application program 103. The database management system 100 includes a dictionary 1001, history management information 1002, management definition 1003,
Query converter 1004, history information manager 1005, query converter
1006, a data access unit 1007, and a data analysis unit 1008. The database management system 100 is an application program 1
The database 101 and the history storage unit 102 are operated by an operation command issued by 03.

The database 101 is a storage device for storing data according to the definition.

The history management unit 102 is a storage device for storing pre-update information of the database 101. Dictionary 1001
Accumulates system information in the database 101.

The history management information 1002 accumulates the system information of the history storage unit 102, and when the pre-update information of the database 101 is newly stored in the history storage unit 102, the history information is stored in the history management information 1002 correspondingly. The link information is stored for the pre-update information of the unit 102.

The management definition 1003 is definition information of the history storage unit 102, and stores the pre-update information of the database 101 in the history storage unit 102.
Define the conditions to be stored in.

The query analysis unit 1004 includes the application program 103
It receives a database operation request, determines the content of the operation request, determines whether the operation request from the application program 103 is an operation request of the database 101 or an operation request of the history storage unit 102, and is an operation request of the database 101. At this time, the operation request is passed to the query conversion unit 1006, and the history storage unit 10
When it is the reference request of 2, the operation request is passed to the history information management unit 1005.

The history information management unit 1005 includes the application program 10
When the operation request from 3 is a data reference, the history management information 1002 is referred to, the pre-update information of the database 101 in the corresponding history storage unit 102 is specified, and the operation of the history storage unit 102 is instructed to the query conversion unit 1006. Handing the request, while application program 1
When the operation request from 03 is an update of the database 101, after storing the pre-update information of the database 101 in the history storage unit 102, the history information management unit 1005 receives the key of the pre-update information and the update time information, and It is stored in the management information 1002.

The query conversion unit 1006 receives the location of the data to be obtained from the query analysis unit 1004 or the history information management unit 1005, creates an instruction for operating the database 101 or the history storage unit 102, and sends the command to the data access unit 1007. hand over.

The data access unit 1007 is a query conversion unit 1006
Receiving or updating the data corresponding to the operation request of the application program 103 in the database 101 and the history storage unit 102, and receiving the result. When the operation request of the application program 103 is a reference to data, the data is received from the database 101 or the history storage unit 102, passed to the data analysis unit 1008, and
If the operation request in step 3 is an update of data, an instruction to acquire the pre-update information and an instruction to store the pre-update information in the history storage unit 102 are received from the query conversion unit 1006, and the
01, the pre-update information is received from the database 101, the pre-update information is stored in the history storage unit 102, and the history storage unit 1
The system information of 02 is passed to the history management unit 1005, the database 101 is updated, and the completion of the operation of the database 101 is notified to the data analysis unit 1008.

The data analysis unit 1008 includes a data access unit 1007
Thus, the application program 103 receives the data requested by the application program 103 or the operation completion notification of the database 101, and passes it to the application program 103.

FIGS. 2, 3 and 4 show specific examples of the data structure in this embodiment.

FIG. 2 shows a specific example of the data structure stored in the database 101. In FIG. 2, the customer number is a key that can uniquely identify all data.

FIG. 3 shows a specific example of the data structure stored in the history storage unit 102. In the history storage unit 102, the database 1
The time information is added to the data of 01, and the information before the update is stored.

In this specific example, the time information and the customer number are the keys.

FIG. 4 shows a specific example of the history management information 1002.
One piece of history management information 1002 exists for one piece of data, with the key as the root 401 and the time at which the database 101 was updated as a child.
Have multiple as 402.

FIG. 5 shows the operation when there is an operation request to add, change, or delete data from the application program 103 to the database 101. FIG. The operation in the case of specifying and referencing is described.

In FIG. 5, a database management system
The operation of 100 starts at block 500.

In an operation block 501, the query analysis unit 1
004 receives an operation command of the database 101 and the history storage unit 102 issued by the application program, and enters an operation block 502.

In an operation block 502, the query conversion unit 1
007 is a database for updating database 101
An operation command of 101 and an operation command of the history storage unit 102 for storing the update status of the database are generated and passed to the data access unit 1007, and the operation block 503 is entered.

In operation block 503, when an operation instruction by the application program 103 is added, operation block 504 is executed.
The operation block 505 is entered in the case of change, and the operation block 506 is entered in the case of deletion.

In operation block 504, the database access unit 1007 adds data to the database 101 according to the operation command of the database 101 received from the query conversion unit 1006, and adds the data to the history storage unit 1 according to the operation command of the history storage unit 102.
The pre-update information of the database 101 is stored in 02, and the operation block 507 is entered.

In operation block 505, the database access unit 1007 obtains the pre-update information of the database 101 according to the operation command of the database 101 received from the query conversion unit 1006, and thereafter changes the corresponding data of the database 101 to store the history. The pre-update information of the database 101 is stored in the history storage unit 102 by the operation command of the unit 102,
The operation block 507 is entered.

In an operation block 506, the database access unit 1007 obtains the pre-update information of the database 101 according to the operation command of the database 101 received from the query conversion unit 1006, deletes the corresponding data of the database 101, and deletes the corresponding data of the database 101. The pre-update information of the database 101 is stored in the history storage unit 102 in accordance with the operation command of 102, and the operation block 507 is entered.

In the operation block 507, the history information management unit 1005 stores the key value and the time information of the pre-update information stored in the history storage unit 102 in the history management information 1002,
Enter 508.

In an operation block 508, the data analysis unit 1
In step 08, in response to the end of the data addition / change / deletion processing from the history information management unit 1005, the application program 103 is notified of the end of the database operation request, and the operation 500 ends.

In FIG. 6, a database management system
The operation of 100 starts at block 600.

In the operation block 601, the query analysis unit 1
004 receives an operation instruction of the database 101 and the history storage unit 102 issued by the application program 103, obtains time information to refer to data and a key value of the database 101, passes time information to the history information management unit 1005, and 602
to go into.

In an operation block 602, the history information management unit 1005 searches the history management information 1002 based on the time to be referred to and the key value of the database 101, and obtains the key value of the corresponding pre-update information of the history storage unit 102. Then, the key value is passed to the query conversion unit 1006, and the operation enters the operation block 603.

In the operation block 603, the query conversion unit 1
006 is the history storage unit 102 based on the key value of the corresponding pre-update information.
, An instruction for searching the contents of the database at the time to be referred to is generated, passed to the data access unit 1007, and the operation block 604 is entered.

In the operation block 604, the data access unit 1007 obtains the corresponding history data according to the command for searching the history storage unit 102, passes it to the data analysis unit 1008, and enters the operation block 605.

In the operation block 605, the data analysis unit 1
008 performs type conversion etc. if necessary, and database 101
Then, the reference result of the history storage unit 102 is returned to the application program 103, and the operation 600 ends.

Next, using a specific example, a database 101, a history storage unit 102,
A state change of the history management information 1002 will be described.

FIG. 7 illustrates a state change of the database 101.

The state 700 is an initial state of the database 101.

The state 701 is "customer number = 0003, customer name = C,
This shows a state in which data with a balance = \ 1,000 "has been added. Here, it is assumed that the transition to the state 702 occurred on April 1.

A state 702 indicates a state in which the balance of the data of “customer number = 0003” has been changed to “$ 5,000”. Here, it is assumed that the transition to the state 703 occurred on April 3.

The state 703 shows an example in which the data of “customer number = 0003” has been deleted. Here, the transition to state 704 is 4
Assume that it occurred on March 8.

FIG. 8 illustrates the state change of the history storage unit 102. New data is added to the history storage unit 102 when the database 101 is updated. In this example, the key is "customer number + time".

The state 801 corresponds to the state 701 in FIG. 7 and reflects that “customer number = 0003, customer name = C, balance = ¥ 1,000” has been added to the database 101, and the pre-update information of the database 101 Is added to the history storage unit 102, indicating that there is no data of “customer number = 003” before the state 801.

The state 802 corresponds to the state 702 in FIG. 7 and reflects that the data of “customer number = 003” has been changed, and indicates that the pre-update information of the state 702 has been stored in the history storage unit. I have.

The state 803 corresponds to the state 703 in FIG. 7 and indicates that the pre-update information of the state 703 has been stored in the history storage unit, reflecting that the data of “customer number = 004” has been deleted. I have.

FIG. 9 illustrates a state change of the history management information 1002. When the database 101 is updated and the state of the history storage unit 102 changes, the state of the history management information 1002 changes in conjunction with the change.

The state 901 corresponds to the state 801 in FIG. 8. When the pre-update information is stored in the history storage unit 102, the time information (update time = 4/1) for specifying the pre-update information is stored in the history. Stored in management information 1002.

A state 902 corresponds to the state 802 in FIG. 8, and time information (update time = 4/3) corresponding to the pre-update information is stored in the history management information 1002.

A state 903 corresponds to the state 803 in FIG. 8, and time information (update time = 4/8) corresponding to the pre-update information is stored in the history management information 102.

The embodiment of the present invention has been described above. In FIG. 1, the amount of the pre-update information to be stored as necessary is defined by defining the acquisition time zone and the acquisition frequency of the pre-update information in the management definition 1003. You may make it control.

[0057]

As described above, according to the present invention, by storing information before updating a database in a database management system, the state of the database at an arbitrary time in the past can be restored and used. When the user desires, the processing can be performed by referring to any past database state.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an example that specifically shows data held in a database in FIG. 1;

FIG. 3 is a diagram showing an example specifically showing data held in a history accumulation unit in FIG. 1;

FIG. 4 is a diagram showing an example specifically showing retained data of history management information in FIG. 1;

FIG. 5 is a flowchart showing a database update procedure in FIG. 1;

FIG. 6 is a flowchart showing a reference procedure of a past database state in FIG. 1;

FIG. 7 is a diagram showing an example specifically illustrating a state transition of the database in FIG. 1;

FIG. 8 is a diagram showing an example specifically illustrating a state transition of a history accumulation unit in FIG. 1;

FIG. 9 is a diagram showing an example specifically showing a state transition of history management information in FIG. 1;

[Explanation of symbols]

100… Database management system, 101… Database,
102: history storage unit, 103: application program, 1001: dictionary, 1002: history management information, 1003: management definition, 1004
... Query analysis unit, 1005 ... History information management unit, 1006 ... Query conversion unit, 1007 ... Data access unit, 1008 ... Data analysis unit, 200 ... Specific example of database, 300 ... Specific example of history storage unit, 400 ... History management Specific example of information.

Claims (2)

[Claims] When updating a database, there is provided a means for storing database information before update without requiring a user's special instruction and operating not only the current database but also information before update. Data storage device. 2. The data storage method according to claim 1, wherein the database state at a given time in the past specified by the user can be restored and used using the pre-update information.