JP2000222258A - Database structure changing method, control method of database access request, online system, storing medium storing database operation supporting middleware and storing medium storing shifting utility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable maintenance operation such as the structure change of a database without stopping an online system. SOLUTION: In order to access to a DB, from an application job program 230, the name of the DB is not designated directly but the name of a file is designated. A DB operation supporting middleware 220 manages the name of the DB corresponding to this name of the file and transfers access from the program 230 to the DB corresponding to the name of the file. A DB (copy DB) 215 after change of structure is generated in addition to the DB (original DB) 210 before the change of structure and the name of the DB is related with the file name of the original DB. Next, data of the original DB is copied in the copy DB for each record. In the case where online access occurs during copying, whether a record given an access request is before or after copying is judged to sort the access request.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing method and, more particularly, to a method for enabling a database to be migrated while maintaining an externally accessible state.

[0002]

2. Description of the Related Art In recent years, there has been a demand for running an on-line accounting system for 24 hours continuously in order to improve services of financial institutions. However, if maintenance requirements such as size expansion and structural changes occur in the database that is constantly updated while the online system is operating, conventionally, the database must be re-defined / recreated (unload / re-created) without stopping the online system. reloa
d) could not be performed.

[0003]

SUMMARY OF THE INVENTION One object of the present invention is to enable maintenance work such as changing the structure of a database without stopping an online system.

It is another object of the present invention to enable maintenance work such as changing the structure of a database without affecting the performance of online transactions as much as possible.

Another object of the present invention is to enable maintenance work such as structural change of the database while maintaining the reliability of the contents of the database.

[0006]

SUMMARY OF THE INVENTION According to the present invention, in order to change the structure of a hierarchical DB without stopping online access to the hierarchical DB, first, access from an application program to the database is performed by: Instead of specifying the database name directly, access by specifying the file name. The database operation support middleware manages the database name corresponding to the file name, and directs access from the application program to the database corresponding to the file name. A database (copy DB) after the structure change is generated separately from the database before structure change (the original DB), and the database name is associated with the file name of the original DB. Next, the data of the original DB is transferred to the copy DB for each record. If there is an online access from the application program during copying, the database operation support middleware determines whether the record for which the access was requested is before or after copying, and distributes the access request.
After the transfer of the original DB data to the copy DB is completed, the database operation support middleware is set to use the copy DB in the future.

In another aspect of the present invention, there is provided a method for changing the structure of an original database managed by a database name in an online system and accessed from an application program based on database access information. (A) generating a copy database having a different structure from the original database; (b) storing a database name of the copy database in association with the database access information; and (c) storing the original database.・
Copying at least a part of the information of the contents of the database to the copy database sequentially for each record; and (d) when an access request is received from the application program, the record to be accessed is already copied.
Determining whether or not the record to be accessed has been copied to a copy database; and
Accessing the copy database if the record to be accessed has already been copied to the copy database;
Are provided.

[0008] In the claims of the present specification, "database name" is a concept including information for directly or indirectly specifying a database to be accessed.

In another aspect of the present invention, there is provided a method for changing the structure of an original database managed by a database name in an online system and accessed from an application program based on database access information. (A) generating a copy database having a different structure from the original database; (b) storing a database name of the copy database in association with the database access information; and (c) storing the original database.・
Copying at least part of the information of the contents of the database sequentially for each record to the copy database, and writing a transition completion character at a predetermined position of the record where the copy of the original database has been completed;
(D) when there is an access request from the application program, determining whether or not the record to be accessed has already been copied to a copy database;
(E) accessing the original database if the record to be accessed has not been copied to the copy database; and accessing the copy database if the record to be accessed has already been copied to the copy database. Accessing (f)
After the completion of the processing of the step (c), setting an access to the copy database when there is an access request based on the database access information from the application program. You.

In another aspect of the present invention, there is provided the method of claim 2, further comprising the step of deleting the original database after the processing of the step (f) is completed.

According to another aspect of the present invention, there is provided a database access request control method for passing a database access request from an application program including database access information to a first database or a second database, (A) receiving an access request from the application program; and (b) determining whether there are a plurality of databases corresponding to the database access information included in the access request.
(C) when it is determined that there are a plurality of databases corresponding to the database access information, determining whether data migration is being performed between the plurality of databases; And (e) determining whether the record requested by the application program to be accessed has been migrated if data migration is being performed; and (e) accessing the application program. If the record requesting has not been migrated yet, access the source database of the plurality of databases, if the record has been migrated, the destination database of the plurality of databases Accessing the.

[0012] In another aspect of the present invention, there is provided an online system including an original database managed by a database name and accessed from an application program based on database access information. A copy database having a structure different from that of the database, the database name of which is stored in association with the database access information; and (b) information of at least a part of the contents of the original database is sequentially copied for each record. -When being copied to the database, the access request from the application program is determined by determining whether the record to be accessed is already copied to the copy database, and the record to be accessed is not copied to the copy database. In this case, an online system is provided that includes accessing the original database, and when the record to be accessed is already copied to a copy database, database operation support middleware that accesses the copy database. Is done.

In another aspect of the present invention, a database operation support middleware for controlling the transfer of a database access request from an application program including database access information to a first database or a second database is stored. A storage medium, wherein the database operation support middleware comprises: (a) a program code for determining whether there are a plurality of databases corresponding to database access information included in an access request received from the application program; (B) when it is determined that there are a plurality of databases corresponding to the database access information, a program code for determining whether or not data migration is being performed between the plurality of databases; (C) Data migration work is being performed In this case, the program code for determining whether or not the record requested by the application program to access has been migrated, and (d) the record requesting access by the application program is not yet included. If not migrated, access the migration source database of the plurality of databases,
If the database has been migrated, a storage medium is provided that includes: a program code for accessing a database of a migration destination among the plurality of databases.

In another aspect of the present invention, it is determined whether or not the record requested by the application program to be accessed has been migrated by determining whether the migration complete character is set in the migration source database. 7. The storage medium according to claim 6, wherein the determination is made by checking whether or not the storage medium is present.

According to another aspect of the present invention, there is provided a storage medium for storing a migration utility for migrating information of a first hierarchical database to a second hierarchical database, wherein the migration utility comprises: (a) The data contained in the first hierarchical database is sequentially recorded for each record in a second
Program code to migrate to a hierarchical database of
(B) a program code for accessing a preset definition parameter and acquiring a transition completed character and a transition completed character offset value; and (c) a record that has been transitioned at a position corresponding to the transition completed character offset value. And a program code for writing the completion character in the first record of the first hierarchical database.

【Example】

A. Hardware Configuration Referring to FIG. 1, there is shown a schematic diagram showing an embodiment of a hardware configuration of a host computer 100 of an online system used in the present invention. The host computer 100 includes a central processing unit (CPU) 1 and a memory 4. CPU 1 and memory 4 are connected to bus 2
, A hard disk device 1 as an auxiliary storage device
3 is connected. Floppy disk drive (or recording medium drive 26, 28 such as MO, CD-ROM, etc.)
29) 20 is a floppy disk controller 19 (or IDE controller 25, SCSI controller 2)
7) is connected to the bus 2.

Floppy disk drive (or MO, C
A recording medium driving device such as a D-ROM 20 includes a floppy disk (or a recording medium such as an MO or a CD-ROM).
The floppy disk or the like, the hard disk device 13, or the ROM 14 can cooperate with the operating system to give instructions to the CPU or the like, and record computer program codes for implementing the present invention. This is executed by being loaded into the memory 4. The code of the computer program can be compressed or divided into a plurality of pieces and recorded on a plurality of media.

The host computer 100 further includes user interface hardware, and includes a pointing device (mouse, joystick, etc.) 7 or keyboard 6 for inputting, and a display 12 for presenting visual data to the user. Can have. A touch panel can be used as an input means.
Further, it is possible to connect a printer via the parallel port 16 and to connect a modem via the serial port 15. This host computer 100
Serial port 15 and modem or communication adapter 1
8 (Ethernet or token ring card) or the like, and can communicate with other computers or the like.

The speaker 23 receives, via the amplifier 22, the audio signal that has been D / A (digital / analog converted) by the audio controller 21, and outputs the audio signal as audio. Also, the audio controller 21
Converts the audio information received from the microphone 24 into an A / D
(Analog / Digital) conversion, and audio information outside the system can be taken into the system.

As described above, it can be easily understood that the host computer 100 of the present invention can be implemented by a computer having a communication function including a general-purpose machine and a workstation, or a combination thereof.
However, these components are merely examples, and not all of them are essential components of the present invention.

In particular, since the hardware configuration described here enables online access to the database, the audio controller 21, amplifier 22, speaker 23, microphone 24, and other components required for audio processing, such as an audio controller 21. Keyboard 6, mouse 7, keyboard / mouse controller 5, enabling direct input, CRT 1 for presenting visual data to the user
2. The display device 11, the VRAM 9, the VGA 8, the various recording medium processing devices 19, 25, 27, etc. may not be provided.

B. System Configuration FIG. 2 is a functional block diagram showing the system configuration of the online system according to the preferred embodiment of the present invention.

In the online system according to the preferred embodiment of the present invention, the application programs 101 to 1
09, software such as the hierarchical DB operation support middleware 111, the hierarchical database 121, the communication control middleware 123, and the operating system 125 are running.

The application programs 101 to 109 are applications for accessing the hierarchical database 121 online. In the preferred embodiment of the present invention, the application programs 101 to 109 are implemented as IMS application programs.

Hierarchical DB operation support middleware 111
Controls access to the hierarchical database 121 from the application programs 101 to 109. In the preferred embodiment of the present invention, the hierarchical DB operation support middleware 111 is implemented as a SAIL IMS / ESA application program / operation support program (“SAIL” is a trademark of IBM Corporation).

The hierarchical database 121 stores various information in a hierarchical structure. In a preferred embodiment of the present invention,
The hierarchical database 121 has an IMSDB (“IMS”).
Is implemented as a hierarchical database such as the trademark of IBM Corporation.

The communication control middleware 123 controls communication such as transfer of online transactions. In the preferred embodiment of the present invention, the communication control middleware 123 is implemented as VTAM ("VTAM" is a trademark of IBM Corporation).

The operating system 125 supports each of the above components. In a preferred embodiment of the present invention, operating system 125
It is implemented as MVS ("MVS" is a trademark of IBM Corporation).

C. Operation Procedure Next, the operation procedure of the present invention will be described. FIG. 3 is a conceptual diagram of an online system according to a preferred embodiment of the present invention for explaining a state before migration. In the figure, the application program 230 accesses the hierarchical DB operation support middleware 220 with a “FILE” name defined by a parameter, instead of accessing the hierarchical database with the database name (DB name). Interface section 221 of the hierarchical DB operation support middleware 220
Refers to the contents of the file information storage unit 250 managed by the hierarchical DB operation support middleware 220, and specifies the database to be accessed.

FIG. 4 is a conceptual diagram showing the contents of the file information storage section 250. As shown in the figure, the file information storage unit 250 manages information of a file name 251, a database name 253, and a pair database flag 255. Thus, the file information storage unit 250
Since the file name 251 and the database name 253 are stored in association with each other, the hierarchical DB operation support middleware 220 can access the database corresponding to the file name. The pair database flag 255 is information for identifying whether or not a copy database exists, and details will be described later.

FIG. 5 shows a copy database (DBb).
FIG. 1 is a conceptual diagram of an online system according to a preferred embodiment of the present invention for explaining a state in which is generated. In the figure, a copy database (DBb) 215 is generated with the structure of the original database (DBa) changed. As shown in the figure, the parameter 200 referred to by the hierarchical DB operation support middleware 220 defines DBb as a FILEA database (207), DBa as an original database,
DBb is defined as a copy database (2
05).

The operator first creates a management database 240 to construct such a system configuration. Construction of the management database is possible by executing a batch job. Since the construction of the database is a technique known to those skilled in the art, a detailed description is omitted. Also,
Create a copy database with the structure change defined (the contents are still empty) for the original database.

Then, after defining the parameters as shown in FIG. 6, the operator executes a utility batch job. By executing this utility batch job, the pair database flag shown in FIG. 4 changes from OFF in the initial state to ON. Further, information is set in a management database (management DB) 240.

FIG. 7 is a conceptual diagram of information managed by the management database 240 in the preferred embodiment of the present invention.
As shown in the figure, the management database 240 includes a file name 301, a file status 303, an original database name (original DB name) 305, a copy database name (copy DB name) 307, a transfer completion character 309,
The information includes a transfer completed character offset value 311, a transfer utility status 313, a pointer character 315, and a pointer character offset value 317.

The file name 301 contains the name of a file managed by the management database. In the preferred embodiment of the present invention, the information "FILEA" is included.

The file status 303 indicates that "FILE
Information indicating the status of “A” is stored. Specifically, information for managing three states of “access the original DB”, “access the copy DB”, and “switch preparation state (access the original DB or the copy DB)” is stored. .

The original DB name 305 is the original D
This is information for specifying the DB to be accessed as B. Similarly, the copy DB name 307 is information for specifying a DB to be accessed as a copy DB.

The transfer completion character 309 is information such as characters and symbols written in the first record (root record, parent segment) of the original DB when the record is transferred by the transfer utility. The offset value 311 is information for specifying a location where the transition completion character is to be written. In the preferred embodiment of the present invention, the transfer completion character 309 and the transfer completion character offset value 311 are registered in the management database 240 in advance by the operator before the transfer operation, but may be set in the transfer utility. . The migration utility may write at run time.

The migration utility status 313 stores information indicating the status of the migration utility, such as whether or not the migration utility is being executed, whether or not the migration utility has ended normally or abnormally.

The pointer character 315 is information such as characters and symbols written on the original DB when each dependent record (child segment) is migrated by the migration utility. The pointer character offset value 317 is the pointer character offset value 317. Is the information for specifying the location where is written.

At this stage, “FILEA” is included in the file name 301 of the management DB 240, and
Information indicating access to the original DB is set to DBa for the original DB name and DBb for the copy DB name.

The concept of a pair database is composed of an "original database" before the structure change and a "copy database" after the structure change. The application program 230 accesses using a file name without being aware of the original database or the copy database. In a state where the copy database is prepared, all accesses from the online transaction (application program 230) are made to the original database 210 side.

Hierarchical DB operation support middleware 220
By referring to the management database 240, Original database if the pair database is before migration
1. Access to 2. If the pair database has been migrated, access the copy DB and If the pair database is being migrated, determine whether the record to be accessed is before or after the migration,
An original DB or a copy DB can be accessed.

FIG. 8 is a conceptual diagram of the online system in the preferred embodiment of the present invention for explaining the switch preparation state. After inputting the following commands to the system, the operator executes the migration utility (batch program). Input command: SWITCH PAIRDB, PREP
ARE, FILE = FILEA

In response to the command input by the operator, information indicating that the switch is ready is entered in the file status 303 of FILEA (FIG. 7). In the preferred embodiment of the present invention, the state is switched to the switch ready state by a system command. However, the value of the migration utility status 313 may be automatically changed by executing the migration utility.

When the migration utility is executed, first, information indicating that migration is in progress is set in the item of the migration utility status 313 of the management database 240. next,
The data of the DBa 210 is transferred (copied) to the DBb 215 for each record. The migration utility locks the record being copied, suspends access to the record from the application program 230, and releases the lock after the copy of the record is completed.

At this time, the hierarchical DB operation support middleware 220 accesses the online transaction from the online database to the original database for the pre-migration record, to the copy database for the migrated record, and so on. Sort the access destination.

FIG. 9 shows an embodiment of the transfer procedure of the preferred embodiment of the present invention for transferring all records by the transfer utility while normally operating the online transaction and maintaining data integrity. This will be described with reference to FIG.

FIG. 9 is a flowchart for explaining a procedure when the hierarchical DB operation support middleware distributes application program access during migration in the preferred embodiment of the present invention.

After migrating one root record to the copy database, the migration utility sets the migration completed character at the position of the migration completed character offset of the pre-migration root record on the original database side.

Record reference / update /
To delete, first access the original database side (step 401), and if there is a transfer completed character (step 403), access the copy database side again (step 405) and perform reference / update / deletion processing. If there is no migration completed character, the record has not been migrated yet, so the original database is processed as it is (step 407).

In addition, when inserting a root record by online transaction, a completed character is inserted into the original database and inserted into the copy database (dual insert method). As a result, if the migration utility finds a record in which the migration completed character has already been set, the migration utility does not migrate the record and skips to the migration processing of the next record.

Next, a description will be given of a method of transferring the physical pointer by the transfer utility. The hierarchical database used in the description of the preferred embodiment of the present invention can attach a physical pointer from a parent record.

First, before the migration, the pointer character is set at the position of the pointer character offset in the dependent record pointed to by the physical pointer on the original database 210 side (this can be executed by the Retrieving Get instruction).

Next, if the pointer character of the dependent record for which the migration process is being performed by the migration utility is set, a physical pointer is simultaneously attached to the copy database instead of the migration by a simple INSERT instruction.
Transition by INSERT instruction (can be executed by Sethere Insert instruction).

The migration utility ends normally by migrating all records on the original database side to the copy database.

FIG. 10 is a diagram showing parameters referred to by the migration utility in the switch preparation state according to another aspect of the preferred embodiment of the present invention. In this embodiment, the transfer utility transfers a record (root record) from the original DB to the copy DB and transfers the transfer completion character 323 (“ABC” in FIG. 10) to the original DB side with an offset 321 from the head (FIG. In case “12”), the data is written.

For the subordinate record, the pointer character 327 ("Z" in FIG. 10) is written at the position of the offset 325 ("32" in FIG. 10) from the head. This parameter is also written to the management database 240 when the migration utility is executed. That is, the values of the transition completed character 309, the transition completed character offset 311, the pointer character 315, and the pointer character offset 317 in FIG. 7 are set.

It is desirable that the place where the transfer completion character and the pointer character are written is a place where the application program never writes the transfer completion character. For example, "ABC" is included in a part of the deposit amount field (numerical field).
Is written, it is possible to determine whether or not migration has been completed. If this method is used, the transfer operation can be performed even if there is no reserved area in the root record.

In the preferred embodiment of the present invention,
Migration completion character 3 by parameter to migration utility
09, transition complete character offset 311, pointer character 3
15. The pointer character offset 317 is set and executed, and the information is set in the management DB 240. This information is set in the management DB 240 in advance, and the migration utility refers to the information at the time of execution, and completes the migration. Characters and pointer characters may be written.

Also in the mode using the transfer completed character, as shown in FIG. 9, the original DB is read to determine whether there is a transfer completed character (steps 401 and 40).
3). If the original DB has the transfer completed character, it is determined that this record has been transferred, and the copy DB is accessed and the record is passed to the application program (step 405). If there is no transfer completed character in the original DB, this record is determined to be before the transfer, and the record on the original DB side is passed to the application program as it is (step 407).

As shown in FIG. 11, for the transfer of the dependent record by the transfer utility, first, before the transfer, the dependent record is read using the physical pointer of the original database 210 (step 411). Then, the pointer character "Z" is written into the 32nd byte from the head of the dependent record (step 413). At this time, the before image at the location where the pointer character is to be written is stored in the memory.

Then, it is checked whether or not a pointer character exists in the record to be transferred (subordinate record) (step 4).
15) If there is no pointer character in the record to be transferred (subordinate record), the process moves to the copy side and proceeds to the next dependent record (step 417).

If there is a pointer character in the record to be migrated, the before image of the pointer character portion stored in the memory is restored and migrated to the copy-side DB (Sethere In).
Then, the process proceeds to the next record (step 419). The record migration utility terminates normally by migrating all records in the original database to the copy database. When the migration utility ends normally, information indicating normal end is set in the migration utility status 313 of the management database 240.

FIG. 12 is a conceptual diagram of an online system in a preferred embodiment of the present invention for explaining a state after execution and termination of the migration utility. This state is
When the following command (example) is input, the state shifts from the switch preparation state to the switch completion state. Input command: SWITCH PAIRDB, COMM
IT, FILE = FILEA

The file status of the management DB 240 includes FI
The LEA contains information indicating that the DBb (copy DB 215) is used. For this reason, at this point, access from the application program 230 is always DBb
(Copy DB).

In this way, by switching from the original database to the copy database after the migration processing of all records by the migration utility is completed, the DB after the structure change is used.

FIG. 13 is a conceptual diagram of an online system in a preferred embodiment of the present invention for explaining a state in which a copy DB is operated as a normal DB. In this state, the original DB and the management DB have been deleted.

The operator defines the parameters shown in FIG. 14 and executes a utility batch job to shift the system to this state. When this utility / batch job is executed, first, the original DB 210 and the management DB 240 are deleted, and the database name 253 of the file information storage unit 250 shown in FIG.
Is set to “DBb”, and the pair DB flag 255 is set to OFF.

[0070]

As described above, according to the present invention,
Maintenance work such as structural change of a database can be enabled without interrupting external access or extremely degrading the performance of the access.

[0071]

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a hardware configuration of a host computer or an information terminal of the present invention.

FIG. 2 is a block diagram of processing elements in a preferred embodiment of the present invention.

FIG. 3 is a conceptual diagram of an online system according to a preferred embodiment of the present invention for explaining a state before migration.

FIG. 4 is a conceptual diagram showing the contents of a file information storage unit in a preferred embodiment of the present invention.

FIG. 5 is a conceptual diagram of an online system in a preferred embodiment of the present invention for explaining a state in which a copy DB is generated.

FIG. 6 is a conceptual diagram showing parameters defined by an operator for shifting to a switch ready state in a preferred embodiment of the present invention.

FIG. 7 is a conceptual diagram of information stored in a management database in a preferred embodiment of the present invention.

FIG. 8 is a conceptual diagram of an online system according to a preferred embodiment of the present invention for explaining a switch preparation state.

FIG. 9 is a flowchart for explaining a procedure of controlling application program access during migration according to the preferred embodiment of the present invention.

FIG. 10 is a diagram illustrating parameters referred to by a migration utility in a switch preparation state according to another aspect of the preferred embodiment of the present invention.

FIG. 11 is a flowchart illustrating a processing procedure of a migration utility according to a preferred embodiment of the present invention.

FIG. 12 is a conceptual diagram of an online system in a preferred embodiment of the present invention for explaining a state after execution and termination of a migration utility.

FIG. 13 is a conceptual diagram of an online system according to a preferred embodiment of the present invention for explaining a state in which a copy DB is operated as a normal DB.

FIG. 14 is a conceptual diagram showing parameters defined by an operator for shifting to a DB normal operation state after a structure change in a preferred embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 100 host computer 101 to 109 application program 111 hierarchical DB operation support middleware 121 hierarchical DB 123 communication control middleware 125 operating system 200 parameter definition 210 original DB (DB before structure change) 215 copy DB (after structure change) DB) 220 Hierarchical DB operation support middleware 230 Application program 240 Management DB

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5B075 ND35 PQ05 5B082 DE04 GA02 (54) [Title of Invention] Method of changing database structure, control method of database access request, online system, database operation support middle Storage medium for storing software and storage medium for storing the migration utility

Claims (8)

[Claims] 1. A method for changing a structure of an original database managed by a database name in an online system and accessed from an application program based on database access information, comprising: (a) the original database; Generating a copy database having a structure different from the above; (b) storing a database name of the copy database in association with the database access information; and (c) at least a part of the contents of the original database. And (d) when there is an access request from the application program, determine whether the record to be accessed has already been copied to the copy database. Judgment stage And (e) accessing the original database if the accessed record has not been copied to the copy database, and accessing the original database if the accessed record has already been copied to the copy database. Accessing a copy database. 2. A method for changing the structure of an original database managed by a database name in an online system and accessed from an application program based on database access information, comprising: (a) the original database; Generating a copy database having a structure different from the above; (b) storing a database name of the copy database in association with the database access information; and (c) at least a part of the contents of the original database. (D) successively copying the information of each record into the copy database, and writing the transfer completion character at a predetermined position of the record whose copy of the original database has been completed; and (d) an access request from the application program. (E) determining whether the record to be accessed has already been copied to the copy database; and (e) if the record to be accessed has not been copied to the copy database, Accessing the database and, if the record to be accessed has already been copied to the copy database, accessing the copy database; and (f) applying the application after the step (c) is completed. Setting to access the copy database when an access request is made based on the database access information from the program. 3. The method according to claim 2, further comprising the step of deleting the original database after the processing of the step (f) is completed. 4. A method of controlling a database access request for passing a database access request from an application program including database access information to a first database or a second database, comprising: (B) determining whether there are a plurality of databases corresponding to the database access information included in the access request; and (c) responding to the database access information. When it is determined that there are a plurality of databases, a step of determining whether data migration is being performed between the plurality of databases; and (d) when the data migration is being performed. Indicates that the record that the application program requires access to has been migrated And (e) if the record that the application program requires to access has not been migrated,
Accessing a source database of the plurality of databases and, if migrated, accessing a destination database of the plurality of databases. 5. An online system including an original database managed by a database name and accessed from an application program based on database access information, wherein: (a) the online system has a different structure from the original database. A copy database whose database name is stored in association with the database access information; and (b) when at least a part of information of the contents of the original database is sequentially copied to the copy database for each record, The access request from the application program, determine whether the record to be accessed has already been copied to the copy database,
If the record to be accessed has not been copied to the copy database, access the original database; if the record to be accessed has already been copied to the copy database, access the copy database. An online system including database operation support middleware. 6. A storage medium for storing database operation support middleware for performing control of passing a database access request from an application program including database access information to a first database or a second database, the database comprising: (A) a program code for determining whether there are a plurality of databases corresponding to the database access information included in the access request received from the application program, and (b) the database access. When it is determined that there are a plurality of databases corresponding to the information, a program code for determining whether or not data migration is being performed between the plurality of databases; and (c) performing the data migration. If applicable, the application And (d) if the record that the application program requires to access has not been migrated yet, and (d) if the record requesting access by the application program has not been migrated. ,
And a program code for accessing a migration source database of the plurality of databases and accessing a migration destination database of the plurality of databases when the migration is performed. 7. A determination as to whether a record requested by the application program to access has been migrated,
7. The storage medium according to claim 6, wherein the determination is made by checking whether or not the transfer completion character is set in the transfer source database. 8. A storage medium for storing a migration utility for migrating information of a first hierarchical database to a second hierarchical database, wherein the migration utility comprises: (a) a storage medium for storing the first hierarchical database; (B) a program code for sequentially transferring the included data to the second hierarchical database for each record; and (b) a program code for accessing a predefined definition parameter and acquiring a transfer completed character and a transfer completed character offset value; c) a program code for writing, at a position corresponding to the transfer completed character offset value, the transfer completed character in the first record of the first hierarchical database for a record whose transfer has been completed.