JP2001273175A - Method and system for processing database - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a database storing capacity and to improve database access performance by unnecessitating storing of information required for data mapping into the database and defining of a unique index in data linkage between different databases. SOLUTION: This database processing system is provided with a data mapping file 123 where the set of physical storage information on data in a linking source database 112 and physical storage information on the data in a linking destination database 122 is registered. When the database 112 is updated, update information added with the physical storage information in the database 112 is obtained. Based on the physical storage information of the updated information, the physical storage information in the database 122 is obtained from the file 123 to access, the database 122.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database processing system, and more particularly, to a data mapping technique between a link source database and a link destination database when data is linked between different databases.

[0002]

2. Description of the Related Art Data linkage involves storing the same data in different databases and, when one database (linking source database) is updated by a user program or the like, acquires update information in a data set or the like and updates the database. This is a function that reflects the data in (link destination database) and always makes the contents of both databases the same. In this data linkage, when the update information is reflected from the linkage source database to the linkage destination database, information (data mapping information) for uniquely associating the update target data, that is, data mapping, is required.

Conventionally, in such data linkage between different databases, in order to perform data mapping, it is necessary to store in the database (data) information which is uniquely required and can uniquely identify each data. there were. Also, in general, in order to guarantee the uniqueness of data, it is necessary to define a unique index in which key values constituting the index are different for all data.

[0004]

In the above-mentioned prior art, there is a problem that the database storage capacity is expanded by storing data mapping information necessary only for data linkage in a database and defining a unique index. there were. In addition, by defining a unique index, access (addition,
Index) requires index maintenance processing, and there is a problem that the access performance of the linked source database is degraded. Generally, the link source database is often used online, and it is necessary to minimize the deterioration of access performance.

An object of the present invention is to reduce the storage capacity of a database by eliminating the need to store mapping information for uniquely specifying each data in the database and defining a unique index in data linkage between different databases. The object is to improve the access performance of the interlocking source database.

[0006]

According to the present invention, data physical storage information of a database is used as data mapping information. The data mapping information is created by combining the physical storage information of the data of the linked database and the physical storage information of the corresponding data of the linked database when creating the linked database from the linked database. Keep it.

When the linked database is updated, update information obtained by adding the physical storage information of the data of the linked database to the updated data is acquired, and the physical storage information of the linked database corresponding to the physical storage information is obtained. The data is obtained from the data mapping file, and the data is updated by accessing the linked database based on the physical storage information.

Further, according to the present invention, at the time of reorganizing the database of the interlocking source or the interlocking destination, new physical storage information is obtained and the data mapping information of the data mapping file is recreated.

As a result, in data linkage between different databases, it is not necessary to store information for uniquely specifying each data in the database as in the related art, and as a result, it is not necessary to define a unique index. As a result, the storage capacity of the database can be reduced, and the access performance of the interlocking source database can be improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a system configuration diagram of an embodiment of the present invention. In FIG. 1, 100 is an update information file, and 110 and 120 are database processing systems. For convenience, reference numeral 110 denotes an interlocking source database processing system;
Although 0 is used as the interlocking destination database processing system, this relationship may be reversed. In general, an online processing system or the like often takes a form in which a processing system that has been a linked destination is switched to a linked source and a processing system that was a linked source is switched to a linked destination due to the occurrence of a failure or database reediting. The link source database processing system 110 is the database system 11
1. Consists of an interlocking source database 112. On the other hand, the linkage destination database system processing system 120 includes a database system 121, a linkage destination database 122, and a data mapping file 123. The link source database 112 and the link destination database 122 store the same data. The data mapping file 123 includes, as data mapping information, physical storage information of each data on the linkage source database 112 and the linkage destination database 122.
The above physical storage information is stored in association with the physical storage information. In addition,
It is preferable that the linkage source database processing system 110 also has a data mapping file for the case where the linkage source and the linkage destination are switched, but is omitted in FIG.

The data mapping file 123 is created based on the physical storage information of each database when creating (copying) the linked database 122 from the linked database 112. In the data linkage process, when the linkage source database system 111 updates the database 112 by a user program or the like, the update information file 100 acquires update information to which physical storage information of the update data on the database 112 is added. On the other hand, the linkage destination database system 121 stores the linkage source database 112 added to the update data of the update information file 100.
Data mapping file 1 based on the above physical storage information
23, the corresponding physical storage information on the link destination database 122 is obtained, and the data on the database 122 is updated with the update data obtained in the update information file 100. In addition, in the data addition / deletion processing, the corresponding information in the data mapping file 123 is added / deleted. When the reorganization of the interlocking source or interlocking destination database is performed, the data mapping file 123 is recreated with the new physical storage information.

FIG. 2 is a diagram showing a specific example of physical storage information and a method of obtaining the physical storage information. The physical storage information is, as shown in FIG. 2A, a physical page number 2 in a data set where the corresponding data on the database 200 is physically stored.
Generally, it is composed of 01 and data storage offset information 202 in the page. For example, the data "CCC
.. Are represented by “00020020”. Such physical storage information is often referred to as ROWID, and will be followed here.

FIG. 2B illustrates how to acquire the physical storage information. However, the method of acquiring the physical storage information is not limited to this. In FIG. 2B, the search SQL (S
By describing a special column name (here, “ROWID”) 210 indicating physical storage information as a search target column name at the time of ELECT), it is possible to acquire physical storage information (ROWID) together with search column information. Is shown. Here, as the search result, the physical storage information “000”
20020 "and the search string data" CCC ... "have been returned. In the following specific example, the physical storage information is simply the page only, and the offset information within the page is omitted.

FIG. 3 shows a data mapping file 123.
FIG. 9 is a diagram for explaining the creation processing of the spelling. The creation of the data mapping file 123 is performed simultaneously with the creation of the linked destination database system 122 from the linked source database 112.

In the linkage source database system 111,
Data is read from the interlocking source database 112 and output to the read data file 300 (process 301). At this time, the physical storage information 311 of the interlocking source data is simultaneously acquired and output to the read data file 300 (process 301). The link destination database system 121 stores data in the link destination database 122 based on the read data file 300 (process 302). On this occasion,
The physical storage information 321 of the link destination data is acquired. Then, the acquired physical storage information 321 of the interlocking destination data and the physical storage information 311 of the corresponding interlocking source data of the read data file 300 are combined and registered in the data mapping file 123 (process 303). In the linkage destination database system 121, the data mapping file 123 is completed by repeating this for each data of the read data file 300.

FIG. 4 shows a data mapping file 123.
FIG. 9 is a diagram for explaining data link processing based on the. In the linkage source database system 111, when the linkage source database 112 is updated, the update information obtained by adding the physical storage information of the update data to the update data is updated in the update information file 10.
0 (process 401). In the example, when the data “AAA...” Of the interlocking source database 112 is updated to “XXX...”, This indicates that the updated data “XXX...” And its physical storage information “0001” have been acquired in the update information file 100. I have. In the linkage destination database system 121, first, based on the data mapping file 123,
The physical storage information of the corresponding data in the linkage destination database 122 is obtained from the linkage source physical storage information added to the update data in the update information file 100 (process 402). Next, the link destination database 122 is updated based on the obtained physical storage information and update data (process 403). In the example, the link destination physical storage information “0002” corresponding to the link source physical storage information “0001” is obtained based on the data mapping file 123, and the data “AAA... "XXX ...".

FIG. 5 is a flowchart showing a maintenance process of the data mapping file 123 at the time of data linkage. The maintenance process of the data mapping file 123 is performed on the link source / link destination database 112, 1
It becomes necessary when data on 22 is added or deleted.

In the link destination database system 121,
Update information is acquired from the update information file 100 (step 501), and it is determined whether the information is additional information (step 50).
2). In the case of additional information, the data of the update information file 100 is added to the link destination database 122 (step 5).
03), the linked database 122 of the added data
The above physical storage information is obtained (step 504). Then, the update information file 100 acquired in step 501
The combination of the linkage source physical storage information of the update information (additional data) and the linkage destination physical storage information acquired in step 504 is added to the data mapping file 123 (step 505).

On the other hand, if the update information of the update information file 100 is other than the additional information, the physical storage information of the link source is obtained from the update information (step 506), and the physical information of the link source is obtained from the data mapping file 123. The physical storage information of the link destination corresponding to the storage information is obtained (step 50).
7) Based on the obtained physical storage information, predetermined processing is performed on the link destination database 122 (step 508). That is, in the case of the update process, as described in FIG.
The relevant data in the linked database 122 is rewritten, and in the case of a deletion process, the relevant data is deleted. Thereafter, it is determined whether or not the deletion process is to be executed (step 509). In the case of the deletion information, the mapping information of the physical storage information of the link source and the link destination acquired in steps 506 and 507 is deleted from the data mapping file 123 (step 509). 510).

FIG. 6 is a diagram showing the maintenance processing of the data mapping file when the database is reorganized. The reorganization of the database is a process in which a disorder in the data arrangement caused by addition or deletion to the database is adjusted to an appropriate arrangement by raising and re-registering the data. When the database is reorganized, the physical storage information of the stored data is changed. Therefore, when the interlocking source or interlocking destination database is reorganized, it is necessary to recreate the data mapping file. FIG. 6 illustrates the re-creation of the data mapping file 123 accompanying the reorganization of the interlocking destination database 122, but the same applies to the reorganization of the interlocking source database 112.

In the link destination database system 121,
When performing the reorganization of the database, first, the unload file 610 to which the physical storage information is added is obtained from the reorganization target database 600 (the pre-reorganization database 122).
Is created (process 601). Next, the data is reloaded from the unload file 610 to create the reorganized database 620 (the same database 122) (process 60).
2). In this reloading process, a new and old physical storage information file 630 indicating the correspondence between the new and old physical storage information before and after the database reorganization is created (process 603). Lastly, for the data mapping file 123, the linked physical storage information that matches the old physical storage information of the new and old physical storage information file 630 is stored in the new physical storage information paired with the old physical storage information of the new and old physical storage information file 630. (Process 604).

FIG. 7 shows a flowchart of the maintenance processing of the data mapping file when the database is reorganized. Hereinafter, an example of the reorganization of the link destination database in FIG. 6 will be described.

First, when reorganizing (unloading) the linked destination database 122, the old physical storage information is obtained and output to the unload file 610 (step 701). Next, at the time of reorganization (reload), new physical storage information is obtained (step 702). Next, unload file 61
A pair of new and old physical storage information is created based on the old physical storage information in 0 and the new physical storage information obtained in step 702, and output to the new and old physical storage information file 630 (step 70).
3).

Next, mapping information is input from the data mapping file 123 (step 704). The information having the old physical storage information that matches the linkage destination physical storage information of this mapping information is stored in the new and old physical storage information file 630.
(Step 705), and the new physical storage information in the obtained information is newly changed as the linked physical storage information (step 706). Hereinafter, steps 704 to 70 for all mapping information in the data mapping file 123
6 is repeated (step 707).

Although the embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to this. For example, in the embodiment, information is transmitted and received between the linkage source database system and the linkage destination database system through the read data file and the update information file. However, the data may be directly transferred. Also, as mentioned earlier, the data mapping file may be held by both the processing system of the link source and the link destination.

[0026]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) It is not necessary to store data for guaranteeing unnecessary uniqueness in a database solely for the purpose of data linkage, and it is not necessary to perform unique data addition control when storing data. (2) When the index key information length is equal to the physical storage information length, the mapping information capacity and the unique index capacity are almost the same, but the storage capacity of the database is not necessary because the storage of the data for guaranteeing the uniqueness becomes unnecessary. Is reduced.
Normally, the index key information length is longer than the physical storage information length, and the overall storage capacity is reduced. (3) It is not necessary to define a unique index, so that index maintenance processing at the time of updating access to the interlocking source database becomes unnecessary, and processing performance is improved. (4) In the update processing of the link destination database, by rearranging (sorting) the data to be processed by the physical storage information, the processing is performed in the physical storage order, and the processing performance of the link destination database can be improved.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a specific example of physical storage information and an acquisition method thereof according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of data mapping information creation processing according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram of a data linkage process according to an embodiment of the present invention.

FIG. 5 is a flowchart of maintenance processing of data mapping information at the time of data addition / deletion according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a maintenance process of data mapping information at the time of database reorganization according to one embodiment of the present invention.

FIG. 7 is a flowchart of maintenance processing of data mapping information at the time of database reorganization according to one embodiment of the present invention.

[Explanation of symbols]

 110 linkage source database processing system 111 linkage source database system 112 linkage source database 120 linkage destination database processing system 121 linkage destination database system 122 linkage destination database 123 data mapping file

Claims (4)

[Claims] 1. The same data is stored in different databases, update information of one database (hereinafter referred to as a linked database) is reflected in another database (hereinafter referred to as a linked database), and the contents of both databases are reflected. In the same database processing method, prepare data mapping information that indicates the correspondence between the physical storage information of the data in the linkage source database and the physical storage information of the data in the linkage destination database, and update when the linkage source database is updated Obtain update information obtained by adding the physical storage information of the data in the linkage source database to the data, and obtain the physical storage information of the update data in the linkage destination database from the data mapping information based on the physical storage information of the update information, Accessing the linked database; Scan processing method. 2. A database processing method according to claim 1, wherein, when creating the linked database from the linked database, the physical storage information of the data of the linked database and the physical storage information of the data of the linked database are created. A database processing method characterized by creating data mapping information in combination. 3. The database processing method according to claim 1, wherein at the time of database reorganization, data mapping information is re-created with new physical storage information. 4. A first database system (hereinafter, referred to as an interlocking source database system) including a first database (hereinafter, referred to as an interlocking source database), and a second database storing the same data as the interlocking source database. In a database processing system including a second database system (hereinafter, referred to as a linked database system) having a linked database (hereinafter, referred to as a linked database), the linked database system updates data when the linked database is updated. Means for outputting update information to which the physical storage information of the data of the linkage source database is added. The linkage destination database system stores the physical storage information of the data of the linkage source database and the physical storage information of the corresponding data of the linkage destination database. Data map showing correspondence with Means for holding the update information, acquiring the update information output by the interlocking source database system, obtaining the physical storage information of the update data of the interlocking destination database from the data mapping information based on the physical storage information of the update information, Means for accessing an interlocking destination database.