JP2001117801A - Database synchronizing processor and recording medium recorded with database synchronizing process program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the communication cost and the load on a communication path by decreasing the amount of data needed to synchronize data of a database. SOLUTION: This database synchronizing processor is equipped with a generating means which generates histories of data modifications of a database, a 1st specifying means which specifies the kind of data to be synchronized, a converting means which takes a history including the data kind specified by the 1st specifying means out of the histories generated by the generating means and converts it to the format of electronic mail, and a 1st transmitting means which transmits the electronic mail including the history.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database synchronization processing apparatus and a recording medium storing a database synchronization processing program, and more particularly to a personal computer and a personal digital assistant (PDA).
The present invention relates to a database synchronization processing apparatus and a recording medium storing a database synchronization processing program for realizing data synchronization processing between databases with a smaller amount of information in a database system including a plurality of devices such as e).

[0002]

2. Description of the Related Art Data synchronization of a database (Remote
Synchronization) is known. This is based on the contents of the original primary database,
This is a technique for matching the contents of other databases. As a known technique related to the present invention, Japanese Patent Laid-Open Publication No.
No. 3013 discloses a distributed database system. This system is premised on a system in which a PC terminal or the like to be subjected to database synchronization processing is always connected to a communication network such as a LAN. In systems other than the above-mentioned premise, data synchronization processing is executed by directly connecting the databases by a communication line as needed.

In the above prior art, a PC terminal or the like needs to be constantly connected to a communication line network. The inventor of the present invention proposed in Japanese Patent Application No. 10-181732 solves this problem. As a means for synchronizing the contents, the data (data synchronization information) updated in the main database is attached to an electronic mail and transmitted.

[0004]

In the above proposal, there are a plurality of databases, and in order to synchronize the contents of each database, it is necessary to transmit the data synchronization information to all other databases. For example, when the main database updates a large amount of data as needed and transmits data synchronization information to all the other databases, the amount of data synchronization information transmitted becomes considerable. Portable information terminals such as electronic organizers
It is assumed that the data is always carried and used. If data update accompanying the data synchronization process is frequent, complete data synchronization process becomes physically difficult in terms of storage capacity.

[0005] Further, from the viewpoint of the user of the portable information terminal, the information required for the data synchronization processing may be only a part of the data updated in the main database.
In this case, when all the data synchronization information is transmitted, unnecessary information is transmitted, and the transmission data amount increases. The portable information terminal on the receiving side also becomes difficult to access due to the increase in data in the database. Further, from the viewpoint of cost, it is desirable that the amount of data transferred for the synchronization processing of the database be small from the viewpoint of using a telephone line.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a database synchronization processing device for realizing database synchronization processing based on less data synchronization information and a recording medium recording a database synchronization processing program. Also,
Another object of the present invention is to provide a database synchronization processing apparatus and a database synchronization processing program for realizing database synchronization processing based on less data synchronization information for each user in order to accommodate a plurality of database users. Is to provide a storage medium on which is recorded.

[0007]

In order to achieve the above object, a database synchronization processing apparatus according to the present invention comprises: a creation means for creating a history of data change in a database; and a data designating means for designating a data type for data synchronization processing. 1 specifying means, and from the history created by the creating means,
The apparatus includes a conversion unit that extracts a history including the data type specified by the first specification unit and converts the history into an electronic mail format, and a first transmission unit that transmits an electronic mail including the history.

[0008] The database synchronization processing device further includes a storage unit for storing the data type specified by the first specifying unit for each user, and a reading unit for reading the data type stored in the storage unit. Wherein the converting means extracts a history including the data type read by the reading means from the history created by the creating means and converts the history into an electronic mail format, and the first transmitting means comprises: Sending an e-mail including a history corresponding to the user from the conversion means for each user;
Thus, each user can execute the data synchronization process individually and can operate the information supply device for general use. In addition, since each user can reduce the amount of information required for the data synchronization process by setting in advance, the amount of data required for the data synchronization process is reduced, and the burden on the communication line is reduced.

According to another aspect of the present invention, there is provided a database synchronization processing apparatus comprising: a second designation unit for designating a data type to be subjected to data synchronization processing; a second transmission unit for transmitting the data type; Receiving means for receiving the data synchronization information included in the data by electronic mail, and execution means for executing the data synchronization processing based on the data type included in the data synchronization information.

According to the present invention, there is provided a computer, comprising: a creating unit for creating a history of data change in a database; a first designating unit for designating a data type to be subjected to data synchronization processing; From
A database synchronization processing apparatus comprising: a conversion unit that extracts a history including the data type specified by the first specification unit and converts the history into an electronic mail format; and a first transmission unit that transmits an electronic mail including the history. A computer-readable recording medium on which a program for functioning as a computer is recorded.

According to another aspect of the present invention, there is provided a computer, comprising: a second designation unit for designating a data type to be subjected to data synchronization processing; a second transmission unit for transmitting the data type; A program for functioning as a database device comprising: receiving means for receiving synchronization information by e-mail; and execution means for executing the data synchronization processing based on the data type included in the data synchronization information is recorded. It is a computer-readable recording medium.

[0012]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram of a distributed database system realized by a database synchronization processing device according to an embodiment of the present invention. The distributed database system includes an in-house network 10 and
It comprises an Internet provider 30 connected to the in-house network 10 via the Internet 40, and a remote terminal 20 connected to the Internet provider 30 via a public line 50.

In the in-house network 10, a mail server device 11 and a database device A12 connected to the Internet 40 are connected by a high-speed data communication line such as an in-house LAN 13. The remote terminal 20 is usually located at a remote place remote from the database device A12, and includes a database device B21 connectable to a communication device such as a modem, and a modem 22 connected to the database device B21. The Internet provider 30 includes a mail server device 31 connected to the Internet 40, and an Internet provider 3 connected to the mail server device 31.
0 is the access point of the modem 32 and the public line 50
It is connected to and configured.

In the present invention, the database device A
The number of 12, B21 is not limited, and does not limit the present invention. For simplicity of description, FIG. 1 illustrates a case where there are two database devices. The case where there are many database devices will be described later. Further, the database device B21 is assumed to be a terminal that exists in a remote place remote from the database device A12 and cannot be directly and constantly connected via a communication line such as a LAN.

Further, depending on the system, the database devices A12 and B21 mean only a large-capacity storage device, and a data processing device may be separately provided. However, in this embodiment, for simplification of description, , The database devices A12 and B21 also incorporate a data processing device, and realize the function as the database synchronization processing device in the present invention. That is, the "database synchronization processing device" of the present invention is defined as the database devices A12 and B2.
1, each database device has a function of independently adding / changing / deleting data to its own database. Also, the database devices A12, B21
Is a function for viewing the received e-mail, a function for requesting the mail server devices 11 and 31 to transfer the e-mail destined for the user stored in the server, receiving the e-mail, and transmitting a newly created e-mail. It has a function to do.

FIG. 2 is a block diagram showing an example of the internal configuration of the mail server device 11, the database devices A12 and B21 shown in FIG. This configuration is based on the CPU 1
00, a memory such as a ROM 101 and a RAM 102, a storage device 103, an input / output interface 104 and an input / output device 105, a display control unit 106, and a display device 10.
7, communication interface 108 and communication board 109,
And a recording medium reading device 110.

A personal computer is generally used for the mail server device 11 and the database device A12 in the in-house network 10. A portable information terminal is generally used for the database device B21 connected to the modem 22. In the present embodiment, the mail server device 1
1 is connected to the Internet 40 and can exchange electronic mail from outside the LAN.

The electronic mail of the synchronization information created during the database synchronization process is transferred between the databases as follows. The e-mail transmitted by the database device A12 is received once by the mail server device 11, and then transmitted to the outside such as the Internet. An e-mail addressed to the remote database device B21 is also transmitted by the same route, and is once received by the mail server device 31 such as the Internet provider 30 on the Internet, and is sent from the mail server device 31 to the database device B21 according to a request from the database device B21. Will be transferred.

In the case where the electronic mail transmitted from the remote database apparatus B21 to the database apparatus A12 is an Internet mail, when the database apparatus B21 is connected to the access point of the nearby Internet provider 30, the mail server of the Internet provider 30 is used. The data is transferred to the device 31 and stored. Thereafter, the saved e-mail is sent to the Internet provider 30
Is transferred from the mail server device 31 to the mail server device 11, and is transferred to the database device A12 in response to a request from the database device A12.

The mechanism of the above e-mail is the same as the general mechanism of Internet mail transfer. The type of communication protocol between the devices is not related to the present invention and is not limited. Generally, POP3 or SMTP over TCP / IP protocol is used for LAN communication.
An e-mail transfer-related protocol called is used.

FIG. 3 is a diagram exemplifying a database structure in the database synchronization processing device of the present invention. In this database structure, a table-type database in which one record is composed of a plurality of fields is illustrated. In this example, one record is a 10-digit “data ID”.
301 "," date 302 "," content 303 ",
It is composed of four data fields of “location 304” and “classification 305”. Each record has a unique number called a data ID. This data ID
Is a number that is completely unique in the database environment of the present invention and is guaranteed to be the same record if there are records with the same ID number in a plurality of databases.

FIG. 4 is a diagram exemplifying the format of an electronic mail created in the database synchronization processing device of the present invention. The e-mail created in the present invention includes a destination [To] 501, a sender [from] 502, and a date [Date] 50.
3, the title [Subject] 504, the text 505 and the like. The format of the e-mail in the present invention may be any format of the e-mail including the above information, and the format of the e-mail used does not depend on the specific format. For example, R that is frequently used on the Internet
FC (Request For Comment) 822 standard (Standard fo
rmat for APRA Internet text message) specifies the format for expressing the above items.

Next, the concept of the database synchronization process will be briefly described. Usually, when it is desired to operate a database of the same content by two or more database devices, one of the database devices is operated as a main database, and the other database device performs only data operations as a client. There are many. If the user cannot access the main database directly because of the remote location, a copy of the main database is also prepared in the remote database device, and the remote user usually accesses the replicated database. . For example, there is a method of synchronizing a schedule in a personal computer or a portable information terminal, or a database of an address book (to have exactly the same contents), and the like.

Even if each database device is based on the same database data, there is data input or change in only one database device.
Naturally, a difference occurs in the contents of the database in the database device. The database synchronization process is performed to resolve the difference that has occurred. In the present embodiment, a description will be given on the assumption that the database device A12 is the main database device, and the data synchronization process is also performed by the database device A12. However, the database synchronization processing device of the present invention can also be applied as a database device having an equal position without a main / sub position.

Next, the operation of the database synchronization processing device according to the first embodiment of the present invention will be described. As described above, the database device A12 has a data change (addition / change / deletion) function in the database, and the database of the database device A12 is updated as needed. For example, information such as the location and date and time of movie screenings and concert performances is registered in the database by each organizer.

FIG. 5 is a diagram exemplifying a screen for designating the classification of user data in the database device of the present invention. The user data is data of items necessary for the synchronization processing of the database, and is set according to a request of the user. Based on the screen shown in FIG. 5, the data classification to be transferred is designated by the user to the database device A12. For example, when “classic” is specified by the user as the desired classification 53, “desired classification = classic” is stored in the database device A12 together with the name 51 and the address 52.

The data classification designation screen shown in FIG. 5 can be used in each of the database devices A12 and B21. The user of the database is a database device B21.
The data type is designated via a keyboard or the like in accordance with the data type designation screen, and transmitted to the database device A12 by e-mail. In the database device A12, the data classification specified by the user is stored in the storage device 103 (FIG. 2).
) In a data area A (not shown). Also,
As another embodiment, each user may notify the database device A12 of the data classification to be specified by mail or the like. In this case, in the database device A12, a data classification is specified by the operator from a specification screen via a keyboard or the like, and the specified data classification is stored in the data area A of the storage device 103.

FIG. 6 is a diagram exemplifying data change history data indicating the history of data change (addition / change / deletion) of the database shown in FIG. This data change history data is stored in the storage device 103 of the database device A12. The data synchronization information indicates what changes have been made to each of the data indicated by the data ID numbers on the left side of the table. The target data ID number 401 indicates the number of each changed record. The change category 402 indicates the content of the change (addition / change / deletion). Change date 403
Represents the changed date and time. The change contents 404 are the first to first.
It shows specific changes to the fourth fields 302 to 305 (see FIG. 3). Normally, the data entry person also inputs the change contents 404. Each time data change (addition / change / deletion) occurs for one piece of data, the data synchronization information is added to the data change history data.

FIG. 7 is a flowchart showing data synchronization information creation processing based on data change history data in the present embodiment. When a data change (addition / change / deletion) occurs (step a1), its processing classification (addition / change)
(Change / deletion) (step a2), and processing corresponding to each processing classification (step a3-a6, step a7-a).
9. Steps a10-a14) are performed.

In the case of addition processing, a unique data ID number 401 is newly created (step a3), registered as data synchronization information (see FIG. 6) (step a4), and "added" as the change classification 402. And register (step a
5) Add and register the changed content 404 (step a)
6). In the case of deletion processing, the data ID to be deleted
The number 401 is confirmed (step a7), registered in the data synchronization information (step a8), and the change classification 402 is registered as "delete" (step a9). In the case of the change (correction) process, the data ID number 401 to be corrected is confirmed (step a10), registered in the data synchronization information (step a11), and the change classification 402 is registered as "change" (step a11). a12), the contents of the changed field are confirmed (step a13), and registered in the changed contents 404 of the data synchronization information (step a14). After each of the steps a6, a9, and a14, the data synchronization information change date 4
03 is registered with the current date (step a15), the data change processing is ended (step a16), and the process shifts to the next data change processing wait. The data synchronization information manages all changes in each database.

FIG. 8 is a flowchart showing an electronic mail creation process based on data change history data in the present embodiment. The database device A12 converts the change history data into a format that can be transmitted by e-mail. This converts only data corresponding to the desired classification (see FIG. 5) specified by the user into an electronic mail as data synchronization information to be transmitted.

When the synchronization information mail creation process is started (step S601), the mail address of the user is confirmed and set as the destination [To:] of the e-mail (step S601).
602). The data classification specified by the user is confirmed and stored in the data area A (step S603), and the data change history data (see FIG. 6) is read (step S6).
04), the record pointer is set to the first record (step S605).

Next, in the read data change history data, the contents of the fourth field (classification) in the change contents 404 column are confirmed (step S606), and are compared with the contents of the data classification specified in advance by the user. Then, it is confirmed whether or not the data matches the specified data classification (step S607). If they match, the data corresponding to the data classification is added to the end of the e-mail (step S608). For example, if "classic" is specified as the "data classification", only data for which "classic" is set in the fourth field will be extracted.

The above processing is performed for all records in the data change history data. That is, the record pointer is raised (step S609), and it is determined whether or not it is the end of the record (step S610). If it is not the end, the process returns to step S606, and if it is the end, the process ends (step S611).

Next, the database device A12 transmits data synchronization information after the designated date and time to the database device B21 as an electronic mail. In the example shown in FIG. 4 described above, a preset title “Sync-Information (synchronization information)” is written in the title [Subject] 504, and information extracted according to FIG. The database device A12 transmits the e-mail according to a predetermined procedure. In the transmission procedure, in the case of Internet mail, a protocol called SMTP is used, and other mails are also transmitted according to predetermined protocols. Transmission procedures using these protocols do not limit the present invention.

The database device B21 has a function of receiving an electronic mail, and receives an electronic mail from the database device A12 as a main database. The receiving procedure is a protocol called POP3 in the case of Internet mail, and other mails are also received according to predetermined protocols. The receiving procedure according to these protocols does not limit the present invention.

FIG. 9 is a flowchart showing an electronic mail receiving process according to the present embodiment. An e-mail reception process is started (step b1), and it is determined whether the received e-mail is an e-mail for synchronization processing of a database (step b2). This process
For example, in the title [Subject] 504, the title "Sync-Informatio
n (data synchronization information) "is described. If it is not the data synchronization processing mail, the mail processing other than the data synchronization processing is performed (step b3). , Database device B2
1 retrieves data synchronization information present in the received e-mail (step b4), performs data synchronization processing on the database of the database device B21 based on the retrieved information (step b5), and ends the processing. (Step b6).

FIG. 10 is a flowchart showing a database synchronization process (step b5 in FIG. 9) in the present embodiment. When the data synchronization process is started (step b11), first, the record pointer of the data synchronization information is initialized (step b12). Next, the record of the corresponding record pointer of the data synchronization information is confirmed (step b13), the change classification 402 of one record of the data synchronization information is confirmed, and the process proceeds to each process according to the contents of the change item (step b14).

In the case of addition, the target data ID number 401 is confirmed (step b15), the change content 404 is confirmed (step b16), a record having the same data ID number 401 as the data synchronization information is registered, and The contents of the data are changed to the data synchronization information 404 and registered in the database of the database device B21 (step b1).
7).

In the case of deletion, the target data ID number 401 is confirmed (step b18), and the record having the same data ID number 401 as the data synchronization information is deleted from the database of the database device B21 (step b1).
9). In the case of a change, the data ID number 401 is confirmed (step b20), and the same data ID as the data synchronization information.
The record with the number 401 is retrieved from the database (step b21). Next, the data of the extracted record is replaced with the changed content 404 of the data synchronization information (step b22), and registered again in the database of the database device B21 with the same data ID number 401 (step b23). The above is performed in order of the number of records stored as the data synchronization information (steps b24 and b24).
25), end the database synchronization process on the receiving side.
Note that, in the present embodiment, an example is shown in which the data change of the database device A12 is reflected in the database device B21, but the reverse process can be performed by a similar procedure. According to the above procedure, the data synchronization processing is executed between the database apparatuses to be subjected to the data synchronization processing based on the data classification specified in advance by the user.

Next, a database synchronization processing apparatus according to a second embodiment of the present invention will be described. In the present embodiment, it is assumed that there are a plurality of users and a database device B21 corresponding to each user. In this example, the database device A12 is used as a basic database, and the date and place of a concert or screening such as rock / popular music / movie / drama / lecture are updated as needed. The database device A12 has a user registration / management function, and the user uses the registration screen (see FIG. 5) provided from the database device A12 to enter a name 51, an address 52, and a desired classification 53. Specify and specify database device A12
Is registered in the storage device 103. In this example, rock / popular music / movie / drama / lecture is input as the category item to be received.

FIG. 11 is a diagram illustrating a user information management table. This table is stored in the database device A12.
Created by the user registration / management function. In FIG. 11, each piece of information is entered in the fields of a name 61, an e-mail address 62, a classification 63 of each data, and a synchronization execution date and time 64. Further, the database device A12 has a function of storing data of data change (addition / change / deletion) history (see FIG. 6) as data synchronization information. Further, the database device A12 has a function of converting the change history data into a format that can be transmitted by e-mail. According to this function, in addition to the contents described in the above-described first embodiment, each user converts only relevant data into an e-mail format according to the data classification specified by the user.

FIG. 12 is a flowchart showing an electronic mail creation process based on data change history data according to the present embodiment. When the e-mail creation process for each of the plurality of users is started (step S620), first, the user information management table (see FIG. 11) is read (step S621), and the record pointer is moved to the first user data. It is set (step S622). Acquire the user information record and the data classification specified by the user. Subsequent steps are the same as the above-described processing in the first embodiment (see FIG. 8) (step S62).
3).

That is, the user's address is set in the address field of the e-mail to be created, and the contents of the fourth field which is the "data classification" field is changed from the change contents column of the change history data using the designated data classification. Are sequentially confirmed, and only data having a “data classification” specified by the user is extracted. In this example, only data in which “classic” is registered in the fourth field is extracted. Thus, an e-mail including the data synchronization information addressed to the first user (see FIG. 4) is created. Here, the created e-mail is temporarily stored (step S624).
The above processing is repeated for the number of persons recorded in the user information management table (step S625). When the e-mail is created after all the processes are completed, the created e-mail is transmitted to each database device B21 (step S626).

The database device B21 receives the electronic mail from the main database by the function of receiving the electronic mail. The database device B21 performs a database synchronization process based on the data synchronization information included in the received e-mail. This synchronization process is performed by the first
This is the same as the embodiment. In this example, the database device A
Although the case where the data change of the database in step 12 is reflected in the database device B21 is illustrated, the reverse process is also realized by the same procedure.

The processing in this embodiment (FIG. 12)
In step S626, the electronic mail created for each user is transmitted collectively (step S626). However, the electronic mail may be sequentially transmitted each time an electronic mail is created. In any case, it is sufficient that the data for each user is sequentially read from the user information table (FIG. 11) to execute the creation and transmission processing of the e-mail.

As described above, the present database synchronization processing device is also realized by a program for causing the database synchronization processing device to function. This program is stored in a computer-readable recording medium. In the present invention, the storage units (not shown) of the database devices A12 and B21 shown in FIG. 1 as the recording medium may be program media themselves, and the mail server device 11 may use a CD as an external storage device. A recording medium reading device 110 such as a ROM driver is provided, and a program medium such as a CD-ROM 111 that can be read by inserting a recording medium into the recording medium reading device 110 may be used. In any case, the stored program may be configured to be accessed and executed by a central processing unit (CPU 100), or the read program may be read and stored in a program storage area (not shown). And the program may be executed. It is assumed that this download program is stored in the main unit in advance.

Here, the program medium is a recording medium configured to be separable from the main body, and is a tape system such as a magnetic tape or a cassette tape, a floppy (registered trademark).
Magnetic disk and CD-R such as disk and hard disk
Disk system of optical disk such as OM / MO / MD / DVD, card system such as IC card / optical card, or mask ROM, EPROM, EEPROM, flash RO
It may be a medium that fixedly carries a program including a semiconductor memory such as an M.

Further, transmission / reception means (108, 1 in FIG. 2)
09) may be a medium that carries the program in a fluid manner, such as downloading the program from the Internet 40 via the Internet 40. When the program is downloaded from the communication network, the download program may be stored in the main device in advance, or may be installed from another recording medium. The content stored in the recording medium is not limited to a program, but may be data.

[0050]

According to the present invention, the database synchronization processing can be executed by the user in advance using the e-mail system. At this time, the required data amount can be reduced and the communication cost such as telephone charges can be reduced. . Further, since a general e-mail system that has already been constructed worldwide is used as it is, no special communication line or communication protocol is required, and the construction of the system is inexpensive and easy. Further, data synchronization can be performed with a database device in an in-house network where access from outside is restricted.

[Brief description of the drawings]

FIG. 1 is a block diagram of a distributed database system realized by a database synchronization processing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of an internal configuration of a mail server device and database devices A and B shown in FIG. 1;

FIG. 3 is a diagram illustrating the structure of a database in the database synchronization processing device of the present invention.

FIG. 4 is a diagram exemplifying a format of an electronic mail created in the database synchronization processing device of the present invention.

FIG. 5 is a diagram exemplifying a screen for designating a type of user data in the database device of the present invention.

FIG. 6 is a diagram illustrating data change history data according to the first embodiment.

FIG. 7 is a flowchart illustrating data synchronization information creation processing based on data change history data according to the first embodiment.

FIG. 8 is a flowchart illustrating an email creation process based on data change history data according to the first embodiment.

FIG. 9 is a flowchart illustrating an e-mail reception process according to the first embodiment.

FIG. 10 is a flowchart illustrating a database synchronization process (step b5 in FIG. 7) according to the first embodiment.

FIG. 11 is a diagram illustrating a user information management table according to the second embodiment;

FIG. 12 is a flowchart illustrating an email creation process based on data change history data according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 In-house network 11 Mail server device 12 Database device A 13 In-house LAN 20 Remote terminal 21 Database device B 22, 32 Modem 30 Internet provider 31 Mail server device 40 Internet 50 Public line 100 CPU 101 ROM 102 RAM 103 Storage device 104 Input / output I / F 105 I / O device 106 Display control unit 107 Display device 108 Communication I / F 109 Communication board 110 Recording medium reader 111 CD-ROM

Claims (5)

[Claims] 1. A creating means for creating a history of data change in a database, a first designating means for designating a data type to be subjected to a data synchronization process, and the first means from among the histories created by the creating means. A database synchronization comprising: a conversion unit that extracts a history including the data type specified by a specification unit and converts the history into an e-mail format; and a first transmission unit that transmits an e-mail including the history. Processing equipment. 2. The conversion means further comprising: storage means for storing the data type specified by the first specification means for each user; and reading means for reading the data type stored in the storage means. Retrieves a history including the data type read by the reading unit from the history created by the creating unit and converts the history into an e-mail format. 2. The database synchronization processing device according to claim 1, wherein an e-mail including a history corresponding to the user is transmitted for each user. 3. A second designating means for designating a data type to be subjected to data synchronization processing, a second transmitting means for transmitting the data type, and a receiving means for receiving data synchronization information including the data type by e-mail. Executing means for executing the data synchronization processing based on the data type included in the data synchronization information. 4. A computer, comprising: a creation unit that creates a history of data changes in a database; a first designation unit that designates a data type to be subjected to data synchronization processing; and a history that is created by the creation unit. A database synchronization processing apparatus comprising: a conversion unit that extracts a history including the data type specified by the first specification unit and converts the history into an electronic mail format; and a first transmission unit that transmits an electronic mail including the history. A computer-readable recording medium on which a program for causing a computer to function is recorded. 5. A computer, comprising: a second designation unit for designating a data type to be subjected to data synchronization processing; a second transmission unit for transmitting the data type; and receiving data synchronization information including the data type by e-mail. A computer-readable program for recording a program for functioning as a database device comprising: a receiving unit; and an execution unit that executes the data synchronization process based on the data type included in the data synchronization information. Recording medium.