JP2000259460A - Database system and data updating system therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessiate that chain information is updated into final management record page and to reduce the prolongation of processing time caused by exclusive cancel waiting at the time of managing record reference by preparing a dummy page at the end of a data page group. SOLUTION: On the basis of the execution request of record adding processing, a record processing control means 1 reads a managing record 61 in a managing page storing the area managing information of a record table in a relevant data base 6, reads a dummy page 63 into an update buffer and reads a final data base out of the data base into the update buffer. When the data record can not be stored in the final data page, an additional page securing means 2 is activated, an empty page is found out from a database file, maintenance processing of inter-page chain is performed with this empty page as a new final data page and after control is returned from the additional page securing means 2 to the record processing control means 1, processing is performed for inserting data to the newly secured non-used page.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data updating system in a database system, and more particularly to a database system for updating data in accordance with a management record of the database and a data updating system thereof.

[0002]

2. Description of the Related Art An example of a data updating method in a conventional database system is described in Japanese Patent Application Laid-Open No. 59-02068. This conventional data update method has a sequential file in which each page is added with page information indicating its own page number, previous page number, next page number, and the number of records in a page, and information at the time of file access. File control block, auxiliary storage device for storing the same, means for loading the arithmetic control unit and file control block into main memory, means for updating the file control block, and addition / deletion for changing the page information of the updated page Means.

The conventional data updating method having such a configuration operates as follows. That is, the insertion position (page) is retained for each process when a record is added, and if there is no space in the inserted page, the record stored in the relevant page is transferred by following the inter-page chain to the previous and next pages. Then, a method of creating an empty area and storing records therein, and, if no empty area is found, inserting a new page by replacing a chain between pages before (or after) the page at the insertion position. It describes a technique for adding records to a page.

Japanese Patent Laid-Open Publication No. 9-330254 discloses a similar database updating method. When a new record storage area is secured, the database file is not allocated when the area is secured without using the host computer communication function means. Simplify the control process in securing the record storage area by newly registering it in the area management page and reading out the area management page as needed so that the management area of the latest record storage area can always be retrieved. And shorten the processing time.

Japanese Unexamined Patent Application Publication No. 10-320258 discloses a non-exclusive search request that may read data stored in an exclusive unit during a database update process by another user. It describes that a search process is speeded up by determining whether or not a search request is made and not performing exclusive control.

[0006] Japanese Patent Application Laid-Open No. 7-105060 discloses that the number of records stored in a page is limited to suppress contention of page exclusion, and to use the page exclusion method to obtain the same exclusion contention as the record exclusion method. In order to obtain performance, a processing unit such as mapping of records and pages, page management, page exclusion, etc. is provided as record access management, and when multiple records in the same page are accessed simultaneously from different transactions, the upper limit on the number of records is set. It is disclosed that the contention is suppressed to a certain probability or less to prevent turbidity of the accessed page.

[0007]

However, the above-mentioned prior art, in particular, JP-A-59-020068, has the following problems.

The first problem is that when there is no free space in the inserted page, not only is it first attempted to transfer the records already stored in the previous and next pages and make free space in the inserted page, When linking an empty page with the inter-page chain, the page information of the following three pages must be updated at all times. Therefore, there is no empty space in the inserted page and the pages before and after it during data addition processing. That is, it takes time to insert a new page.

The second problem is that if the data insertion position is concentrated at a specific position, page insertion frequently occurs, and the pages before and after the data insertion are subject to simultaneous access control for updating the page information. There is a drop in throughput when sequential addition and sequential reading search run simultaneously.

[0010] The present invention has been made in order to solve the above problems.
It is an object of the present invention to provide an update method in which a dummy page is provided in advance and a high-speed processing can be performed even if there is no empty space in an inserted page or frequent page insertion occurs in a database update process.

[0011]

According to the present invention, there is provided a data updating method for updating data of a database in page units, the database having a management record and a dummy page, and a record processing for processing access to the database. Control means, additional page securing means for performing a process of adding a data record under the control of the record processing control means, and additional pages and the preceding and succeeding pages of the additional pages under the control of the record processing control means Chain delay updating means for taking a chain with, a confirmed record referring means for referring to a confirmed result of data update under the control of the record processing control means, and managing the updated page of the data record by the additional page securing means. And an information storage area containing updated page management information.

Further, according to the present invention, a dummy page whose page number does not change under management of a management record for managing the database in record units is prepared in the database in advance, and a new data record is added to the database when a data record is added. When a data page is needed, the last page preceding the dummy page is linked, and when a record is added to the database, if there is no free space for storing the record, The last page of data is inserted immediately before the dummy page, and the last page number of the data is written in the page header of the dummy page.

Further, the present invention functionally prepares in advance a dummy page whose page number does not change from the management record of the database, and when a new data page is required when adding a data record, the dummy page is prepared. Linking the last page to the preceding (PRIOR) side of the process reduces update processing on the management record, and suppresses an increase in processing time due to exclusive waiting for another process referring to the management record to release the update lock, thereby improving throughput. It is intended to improve.

Also, a dummy page and a PR of the dummy page
Updates to the last page of data that is located on the IOR side and that already contains data are not performed every time a new page is added, but updated images for these pages are temporarily stored in the information storage area and stored in the database. Immediately after the quiesce point is established when data is established, the update update holding section for the dummy page or the last page of data is reduced by performing the delay update control for the first time, and the simultaneous running performance of the reference system processing operated by other processes is reduced. It is intended to provide a configuration for improvement.

Further, according to the present invention, referring to FIG. 1, when a new page is inserted into the database 6 in accordance with the data adding process, a page is inserted between the dummy page 63 and the data page group 62. A page is added by linking with an inter-chain, but the added page securing processing means 2 does not update the chain of pages already existing when adding a page to the PRIOR side of the dummy page 63, but only updates the updated image. Is stored in the update management information storage area 51, and the chain delay updating means 3 updates the real page at the time of establishment of the quiesce point where the data immediately after being stored in the database is established, thereby reducing updates to the management record 61. When referencing data, there is a case where data that has been added but a stationary point has not been established is intentionally processed without being read. , Thereby improving the shortening simultaneously running of processing time by eliminating an exclusive release wait be updated lock likened to the data last page and the dummy page is not applied by placing record reference means 4.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described.
This will be described in detail with reference to the drawings.

(Configuration of the Present Embodiment) Referring to FIG.
The data update method in the database system according to the embodiment of the present invention includes a record processing control unit 1, an additional page securing unit 2, and a chain delay updating unit 3 included in a data processing device (not shown) operated by program control. A fixed record reference means 4, an information storage area 5 for storing program control information and updated page management information 51 included therein, a database 6, a management record 61 constituting the database 6, a data page group 62, and a dummy page 63.

Here, the database 6 includes a data page group 62 for storing data records, a first page number of the data page group 62, and a data page group 62.
And a management record 61 holding the page number of the dummy page 63. In a database management system, the unit of data operation is a record (also referred to as a tuple), mapping of a record to a page which is an input / output unit between an external storage device, management of the page on a memory, and free space. It includes a record access management means for managing eviction when there is a shortage, an exclusive access control between transaction (transceiver) of a record in operation units, and the like.

The updated page management information 51 included in the information storage area 5 is used when a new data page is required by a record adding process to the database 6.
Records information about chains between data pages.

The record processing control means 1 adds a record to be processed to an area in which records can be stored, and updates the record when a processing request such as record addition or update processing to a database file is given from a user. Is performed to perform.

When a record search processing request is given, the record processing control means 1 searches a data record in a data page of the database 6 for a record matching a search condition, and performs a record search including processing, editing and the like. Control for performing processing is performed. Further, when a request for establishing a quiesce point, which is a state immediately after storage in the database, is given by a database update (COMMIT) command, if there is an inter-page chain that has not been actually updated, it is updated with correct information. Control is also performed.

Further, when the record processing control unit 1 gives a request for additional processing, the additional page securing unit 2
If there is no free area for storing records in the data storage page at the end of the inter-page chain, the record processing control unit 1 starts up, searches for an empty page, and searches for a series of pages secured as a database in the inter-page chain. Control to link to the page.

Particularly, when the last data page at the time of establishment of the quiesce point where data immediately after storage in the database is established and the dummy page 63 at the end of the inter-page chain are updated, the actual page is not updated. Then, the updated image is stored in the updated page management information 51.

Under the control of the record processing control means 1, the chain delay updating means 3 does not update the real page by the additional page securing means 2 but updates the updated page management information 5
The inter-page chain information temporarily stored in 1 is written back to the actual page when the quiesce point is established, thereby controlling the inter-page chain to be consistent.

Under the control of the record processing control means 1, the confirmed record reference means 4 reads the page on which the update lock has been locked in the data addition processing without locking, thereby waiting for the release of the exclusion. Instead, control is performed so that search processing can be continued.

In particular, when a forward search is performed by tracing a chain between data pages, when an update lock is applied to the last page of data by another process, it is determined in advance which update lock is applied to which page. The determination is made based on the information of the update page management information 51.

(Operation of the Present Embodiment) Next, the operation of the embodiment of the present invention will be described in detail with reference to the system configuration diagram of FIG. 1 and the operation flowcharts of FIGS.

First, the operation of each means shown in FIG. 1 will be outlined. When a request to execute record addition processing is given from a user program, the record processing control means 1
First, the management record 61 in the management page in which the area management information of the record table in the corresponding database 6 is stored is read from the database 6 and the dummy page 63 at the end of the chain between data storage pages is updated and locked. , Read into the update buffer and its preceding (PRI
(OR) The update lock is applied to the last page (the last page of data) in which data is actually stored in the direction,
Read from the database into the update buffer.

Next, it is checked whether or not there is a free area in the last page of the data in which the data record to be added can be stored and whether or not the number of storable records has been exceeded. If it is determined that it is not possible, the additional page securing means 2 is started, a free page (unused page) is searched from the database file, and this is set as a new data final page, and the maintenance processing of the inter-page chain is performed. After returning from the additional page securing means 2 to the record processing control means 1, a process of inserting data into a newly secured unused page is performed.

When a quiesce point is established by executing a COMMIT instruction of an update instruction described in a user program, the record processing control means 1 refers to / updates the added data page in another process. It also controls the activation of the chain delay updating means 3 for enabling it.

In the chain delay updating means 3 started by the record processing control means 1, based on the updated page management information 51 held in the information storage area 5, the additional page securing means 2 operated at the time of the data adding processing. The actual update of the previous page number area of the dummy page 63 which was not performed and the actual update processing of the next page number area of the final data page which was the final data page when the still point was established immediately before are performed.

When an execution request for record reference processing is given by the user program, the record processing control means 1 activates the confirmed record reference means 4, and the confirmed record reference means 4 adds data by adding data. Even if the last data page has been changed and the quiesce point has not been established yet, avoid the update lock release wait by the page exclusive control accompanying the data addition process during the search, and wait until the latest quiesce point establishment point. Perform data reference.

(Operation of Additional Page Securing Means 2) FIG.
6 is a flowchart illustrating an operation of an additional page securing unit 2.

The additional page securing means 2 is started when the record processing control means 1 does not have a free area necessary for storing a record in the last page of the data, searches for a free page from the file, and dummy-checks the free page. It is inserted just before the page 63, this is set as a new data last page, and is called to store a data record requested to be added thereto.

The additional page securing means 2 started by the record processing control means 1 first finds a free page from the file and reads it with an update lock (step 201).

In order to make this empty page (hereinafter referred to as a newly reserved page) the last page of data, the next page number storage area in the page header of the page is linked to the end of the inter-page chain. The page number of the dummy page 63 is set (step 202).

Next, it is determined whether or not the added last page number is registered in the updated page management information 51 (step 203).
If it is not registered in No. 1, it is determined that a newly secured page is to be added for the first time after the establishment of the immediately preceding static point (NO in step 203), and is stored in the previous page number storage area of the newly secured page read in step 201. After setting the final page number registered in the updated page management information 51, that is, the page number of the data page in which the final data was stored at the time of establishment of the last still point, the file is written back to the file (step 204). .

As a result, the dummy page number is set in the next page number storage area and the last data page number (fixed last page number) at the time of establishment of the quiesce point is set in the previous page number storage area in the header section of the newly secured page. That is, it is done (step 205).

On the other hand, if the last page number to be added has already been registered in the updated page management information 51 in step 203, at least one additional page is added between the time when the last stationary point was established and the current record addition processing. It can be determined that the page securing means 2 is operating (step 203).
In the case of YES), the last page number registered in the updated page management information 51 is set in the previous page number storage area of the newly reserved page, and then the file is written back (step 206).

In this case, the dummy page number is stored in the next page number storage area in the header section of the newly allocated page, and the last page of the latest newly allocated data after the still point is established in the previous page number storage area. The page number (added last page number) is set.

In the case of YES in step 203, based on the added last page number registered in the updated page management information 51, the most recently secured data last data (added last page) is read (step 20).
7), Step 2 in the page number area next to the last page to be added
The page number of the newly secured page found in 01 is stored (step 208), and the added final page is written back to the file (step 209).

By the processing from step 207 to step 209, the next page number in the header portion of the added last page is updated from the page number of the dummy page 63 to the page number of the newly secured page.

Finally, the last page number of the dummy page 63 is not updated, but the added last page number of the updated page management information 51 is re-registered with the page number of the newly secured page (step 210), and the data record The first record of the newly secured page is set as the storage destination (step 211), and control is returned to the record processing control means 1.

After that, in the record processing control means 1 to which the control is returned, when the additional page securing means 2 notifies that the record can be stored, the record storage page number and the record position are returned together. Therefore, it is possible to write the record image requested to be added to the corresponding page, and to operate the record addition process normally.

When the record processing control means 1 receives a message indicating that record storage is impossible, for example, when there is no empty page in the file of the database 6 and the database file itself overflows, Needless to say, it is possible to return the result of the record addition failure to the request source of the record addition processing.

Further, when additional processing is simultaneously performed in a plurality of processes, the additional page securing means 2 first locks the dummy page 63 with an update lock and performs shared exclusion control. It is obvious that the additional processing is serialized so as not to operate.

(Operation of Chain Delay Update Means 3) FIG.
5 is a flowchart showing the operation of the chain delay updating means 3.

When the record processing control means 1 executes the COMMIT instruction, the chain delay updating means 3 uses the page header upon activation of the additional page securing means 2 based on the updated page management information 51 held in the information storage area 5. The top page number area of the dermy page 63, which has not been updated, and the next page number area of the final page determined to be the last data storage page at the time of establishment of the most recent still point are actually updated to form an inter-page chain. Invoked to relink correctly.

The additional page securing means 2 started by the record processing control means 1 first determines whether or not an updated final page number is registered in the updated page management information 51 (step 301). For example, it is considered that the additional page securing means 2 has been operated after the establishment of the latest stationary point (YES in step 301), and the dummy page 63
In order to rewrite the previous page number area, the dummy page 63 is read from the file (step 302).

Next, the additional last page number registered in the updated page management information 51 is set in the previous page number area of the dummy page 63 (step 303), and the previous page number of the dummy page 63 is written back to the file (step 303). Step 304).

On the other hand, if the added last page number is not registered in the updated page management information 51 in step 301,
Since it can be determined that the additional page securing means 2 has not operated since the last stationary point was established, the processing from step 302 to step 304 is not performed (NO in step 301).

Next, it is determined whether or not an additional top page number is registered in the updated page management information 51 (step 305).
As in the case of (1), it is considered that the additional page securing means 2 has been operated after the latest stationary point was established (YE in step 305).
S) The final page is read from the file in order to rewrite the next page number area of the final page (step 306).

Next, the first page number registered in the updated page management information 51 is set in the next page number area of the final page (step 307), and the final page is written back to the file (step 308).

On the other hand, if the additional top page number is not registered in the updated page management information 51 in step 305,
Since it can be determined that the additional page securing means 2 has not been operated since the last stationary point was established, the processing from step 306 to step 308 is not performed (NO in step 305).

Finally, the final page number, the added first page number, and the added last page number of the updated page management information 51 are cleared (step 309), and control is returned to the record processing control means 1. The chain delay updating means 3 performs the above operation, and clearly shows the chain relationship by linking the last page of the dummy page 63 or the last page determined immediately before and the next data page which is the additional start page.

(Operation of Fixed Record Reference Means 4) FIG.
5 is a flowchart showing the operation of the confirmed record reference means 4.

The confirmed record reference means 4 is started when a record search request is issued by the record processing control means 1, and performs a sequential search of data records even if data is being added to the database 6 by another process. , Without waiting for exclusive exclusion of the updated page.

Hereinafter, a sequential search process with a search condition for reading data in the storage order will be described as an example. The confirmed record reference means 4 started by the record processing control means 1 first obtains the confirmed final page number from the updated page management information 51 (step 401) and sets the first page number of the data page as the search target page number. (Step 402).

Next, a comparison is made as to whether or not the page number of the search target is the same as the final page number determined (step 403). (NO in step 403).

On the other hand, if the page number to be searched is the same as the final page number determined (YES in step 403),
Since there is a high possibility that the relevant search target page has already been updated locked, the relevant page is read into the reference-only buffer without applying the reference lock (step 405).

According to the condition determination in step 403, the same page can be simultaneously accessed by another process even during the update lock.

Next, it is determined whether or not the search target page is the first page (step 406). If the search target page is not the first page (NO in step 406), the preceding search target page is read before it is read. Since the data page on the PRIOR side to be read is read with the reference lock applied, the reference lock on the page on the PRIOR side is released (step 407).

When the page to be searched is the first page, it is not necessary to release the reference lock of the PRIOR page because another different reference lock is not applied (step 406).
YES).

Next, it is determined whether or not a given search condition is satisfied for each record stored in the search target page (step 408). If there is a match with the condition (YES in step 408), That fact is returned to the request source, and the record contents are returned to the request source (step 40).
9), end the process.

If all the data records in the read page do not match the conditions (NO in step 408), it is checked whether the page is the final page (step 410). If it is (YES in step 410), it is returned to the requesting source that no condition is hit (step 411), and the process is terminated.

If the read page is not the final page (NO in step 410), the next NE
In order to read the page on the XT side, the previous page number is set to a new search target page number (step 41).
2), the processing of steps 403 to 412 is repeated.

By these series of processes, even if data page addition processing accompanying data addition in another process is performed,
The search process can be completed without waiting for exclusive lock release of the update lock and without additionally referencing indefinite additional data before establishment of the quiesce point.

(Specific Example of Database Processing) Next, a specific example will be described. FIG. 5 shows a data page (page B, page C) storing data records of the database 6, a dummy page (page D) located at the end of a chain between pages, and records managing these pages. FIG. 6 is a diagram illustrating a related diagram of a management page (page A) storing the same and the contents of updated page management information 51 held in the information management storage area 5.

The case where a new data page shown in FIG. 5 is written in the database will be described. A chain from the management record 61 to the first page B of the data page group 62 and a chain to the dummy page D are provided.

Between the data pages B and C, page numbers indicating the previous page and the next page are stored in the page header.

Further, page C shows a state in which m data records are stored, and if the next page number D is traced, page D has no previous page number page C and no next page page. It can be seen that the page is a dummy page containing no NULL and no record.

On the other hand, the updated page management information 51 is
It represents a state immediately after the MIT instruction, and contains NULL values (cleared state) of a final page number C and line m, an additional head page number NULL, and an additional last page number NULL.

When one data record is stored from this state, the record processing control means 1 in FIG. 1 refers to page C via page D and determines that there is a free space for storing the record. Add after record m to page C.

At this time, the final page number determined in the updated page management information 51 is changed from the NULL value to “C” (not shown).

Next, consider a case where data addition is further performed. FIG. 6 shows the state of the inter-page chain after the new last page is secured by adding data, and the state of the updated page information 51 at that time.

In FIG. 6, when it becomes impossible to add a new record n of data to page C, the additional page securing means 2 performs the following processing.

First, an unused page X is found in the file (step 201 in FIG. 2), and the page number 'D' of the dummy page D is embedded in the next page number area in the page header of the page X (step in FIG. 2). 202).

Furthermore, since the added last page number of the updated page management information 51 is originally a NULL value as shown in FIG. 5, the final page number “C” is embedded in the page number area before the newly reserved page number X. , Create a header for page X (NO in step 203 of FIG. 2, step 2
04).

Here, the inter-page chain of the next page number area of the final page C and the previous page number area of the dummy page D is not updated (that is, the NEXT of the page C).
Is "D", the PRIOR of page D remains "C"), and the previous page number is newly secured for both the added first page number and the added last page number of the updated page management information 51 for the chain delay updating means 6. The page number “X” of the page X is registered (Step 205, Step 206).

FIG. 7 shows the inter-page chain and the status of the updated page management information 51 when the data addition processing is further repeated.
2 shows the processing result from step 203 to step 210 in FIG. 2 when the additional top page number 'X' is registered in the updated page management information.

As can be seen from FIGS. 5, 6, and 7, the added first page number of the updated page management information 51 includes the true next page number “X” of the final page C, and the added last page. The number includes the true previous page number 'Y' of the dummy page D, and it is imagined that if the page C and the page D are updated based on these at the time of establishment of the stationary point, the chain will be correctly linked. Not difficult.

[0082]

According to the present invention, by preparing a dummy page at the end of a data page group in advance, it is not necessary to update the chain information to the last page of the management record. Since it is not necessary to wait for release of exclusion when referring to a management page as in the case of applying, it is possible to reduce an increase in processing time due to waiting for release of exclusion when referring to a management record.

The inter-page chain, which is the header information of the dummy page and the final page, temporarily stores the chain information in the updated page management information until the stationary point is established. Since update is not entered and the update lock acquired when referring to the dummy page can be released immediately, the simultaneous running performance of the data addition process and the reference process can be increased.

Further, when adding a record to the final fixed page, the update lock must be held until the quiesce point is established. For example, only one record is inserted per page, and a new page must be added without fail. In such a case, the header update is not entered even in the final page, so that the locked update lock can be released immediately like the dummy page.

[Brief description of the drawings]

FIG. 1 is a schematic configuration block diagram of a database update system of the present invention.

FIG. 2 is a flowchart of a database update system according to the present invention.

FIG. 3 is a flowchart of a database update system according to the present invention.

FIG. 4 is a flowchart of a database update system according to the present invention.

FIG. 5 is a diagram illustrating a schematic operation of the database update system of the present invention.

FIG. 6 is a diagram illustrating a schematic operation of the database update system of the present invention.

FIG. 7 is a diagram illustrating a schematic operation of the database update system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Record processing control means 2 Additional page securing means 3 Chain delay update means 4 Confirmed record reference means 5 Information storage area 6 Database 51 Update page management information 61 Management record 62 Data page group 63 Dummy page

Claims (6)

[Claims] 1. A data update method for updating data of a database in page units, said database provided with management records and dummy pages, record processing control means for processing access to said database, and said record processing control. Additional page securing means for performing a process of adding a data record under the control of the means, and chain delay updating for taking a chain of the additional page and the previous and subsequent pages of the additional page under the control of the record processing control means Means, means for referring to a confirmed result of data update under the control of the record processing control means, and information including updated page management information for managing the updated page of the data record by the additional page securing means. A database system comprising a storage area. 2. The database system according to claim 1, wherein the dummy page whose page number does not change from the management record of the database is prepared, and a new data page is required when the data record is added. In this case, the last page is linked to the leading side of the dummy page to reduce the update processing for the management record, and the process that refers to the management record increases the processing time due to exclusive queuing for releasing the update lock. A database system characterized by suppression. 3. A dummy page whose page number does not change is prepared in advance under management of management records for managing the database in record units in the database, and a new data page is required when adding a data record to the database. When the last page of the dummy page is linked, the last page on the side preceding the dummy page is linked, and when there is no free space for storing the record in the case of adding a record to the database, immediately before the dummy page A data update method for a database, wherein a data last page is inserted into the dummy page and the data last page number is written in a page header of the dummy page. 4. The data updating method of a database according to claim 3, wherein a management record storing area management information of a record in the database is read from the database, and the management record is located at the end of a chain between data storage pages. A data update method for a database, wherein an update lock is placed on a dummy page and read into an update buffer, an update lock is placed on a last page existing on the preceding side, and the dummy page is read from the database into the update buffer. 5. The data updating method for a database according to claim 3, wherein an additional first page number is registered in the updated page management information when no additional last page number is registered in the updated page management information for performing information management. If so, the determined final page of the preceding side is read from the management record of the database, and the addition start page number of the updated page management information is stored in the next page number area next to the determined final page. A data updating method for a database, wherein a last page is written in the management record, and an area of an added first page and an area of an added last page of the updated page management information are cleared. 6. The data updating method for a database according to claim 3, wherein, when searching the database, a final page number determined from updated page management information for performing information management is obtained and the search page number for the search is obtained. A first page number is set, a match between the search page number and the final fixed page number is determined, the search page number is read without applying a reference lock, and if the search page number is the first page, the search page number is determined. If there is no record of the database that satisfies the condition, it is determined again whether the search page number matches the final fixed page number, and if they do not match, the search page number is
A data updating method for a database, wherein a next page number next to the search page number is set.