JP2000076218A - Inter-database synchronization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronization system which can secure the synchronization between databases holding a fire wall between them. SOLUTION: The data whose contents are opened to the outside of a company are registered on an external DB 3, and the data which are more detailed than those of the DB 3 are registered on an internal DB 9. A differential data extracting part 17 extracts the data (internal differential data) which are updated in a prescribed period among those data of the DB 9. A data transmitting part 19 transmits the internal differential data, etc., to an external DB server 5 by means of an FTP(file transfer protocol). A differential data extracting part 27 extracts the data (external differential data) which are updated in a prescribed period among those data of the DB 3. A data registering part 29 sets the external differential data on an FTP path, and a data acquiring part 21 intuitively squires the external differential data, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for synchronizing databases between firewalls.

[0002]

2. Description of the Related Art In order to perform synchronization between a plurality of databases, there is a method of connecting each database with a dedicated line. However, laying a dedicated line is expensive. In addition, it is conceivable to use the Internet instead of a dedicated line, but between the LAN (Local Area Network) and the Internet, there is a firewall (hereinafter referred to as FW) that separates both networks at the communication protocol level. It is often provided.

[0003]

Since the FW initiatively prohibits access from a machine outside the FW (Internet side) to a machine inside the FW (LAN side), the conventional database server synchronization function uses Synchronization between remote databases is not possible.

[0004] Further, there is also a problem that the amount of data to be transmitted to the network by the synchronization function of the database server is enormous, so that the Internet traffic capacity is not sufficient.

Accordingly, it is an object of the present invention to provide a synchronization system which enables synchronization between databases separated by FW.

Another object of the present invention is to provide a synchronization system for minimizing the amount of data flowing through a network when synchronizing databases.

[0007]

A database synchronization system according to the present invention includes an internal database server including an internal database inside a firewall, and an external database server including an external database outside the firewall. The internal database server is a data providing unit that provides internal data updated in the internal database to the external database server, and initiatively acquires external data registered at a predetermined location outside the firewall from within the firewall. And a data acquisition unit that updates the internal database with the acquired external data.
An external database server receives the internal data provided by the data providing unit and registers the external data updated in the external database with the data receiving unit that updates the external database with the received internal data at a predetermined location outside the firewall And a data registration unit for performing the setting.

In a preferred embodiment, the internal database server has an internal difference data extraction unit for extracting, as internal data, internal difference data updated for a predetermined period from data of the internal database, The server has an external difference data extracting unit that extracts, as external data, external difference data updated during a predetermined period from data of the external database.

In a preferred embodiment, the internal database server has an internal time storing means for storing the beginning of a predetermined period of the internal difference data, and an internal data for confirming whether or not the external database has been updated with the internal difference data. Update confirmation means, and the external database server has:
It has external time storage means for storing the beginning of a predetermined period of the external difference data, and external data update confirming means for confirming whether or not the internal database has been updated with the external difference data. Accordingly, when the internal data update confirming unit confirms that the external database has been updated by the internal difference data, the internal time storage unit updates the beginning of the internal difference data, and the external data update confirming unit determines that the external data update When it is confirmed that the internal database has been updated with the data, the external time storage unit updates the start of the external difference data.

[0010] In a preferred embodiment, the external database server has means for creating an acquisition completion notification indicating that the external database has acquired the internal difference data, and registering the notification at a predetermined location outside the firewall. The internal data update confirming means initiatively acquires the acquisition completion notification, and confirms the update of the internal database based on whether or not the acquisition completion notification has been acquired. Also, the internal database server has means for creating a reception completion notification indicating that the internal database has received the external difference data and providing the notification to the external database server. The notification is obtained, and the update of the external database is confirmed based on whether or not the reception completion notification has been obtained.

[0011]

FIG. 1 is an overall configuration diagram of a database synchronization system according to an embodiment of the present invention.

An intranet used only in a specific office and the Internet outside the company are connected to a FW (firewall) 1
In this specification, the intranet side from FW1 is called inside FW1, and the Internet side from FW1 is called outside FW1. Outside the FW 1, there is an external database server 5 having an external database 3, and the external database server 5 has an external difference database 7. Further, an internal database server 11 having an internal database 9 is provided in the FW 1, and the internal database server 11 includes an internal difference database 13. (Hereinafter, database is abbreviated as DB.)

The external DB 3 registers data whose contents are disclosed to the outside (for example, information on handled products).
These data are regularly updated (for example, added, deleted, changed, etc.) by the external DB server 5 based on the data of the internal DB 9. Further, the data stored in the external DB 3 is updated by the external DB server 5 at any time due to an event occurring outside the company. An external third party can access the external DB 3 using an information terminal to freely refer to data or freely write desired data.

The internal DB 9 registers more detailed data (including data to be kept confidential to the outside) than the data stored in the external DB 3, and these detailed data are stored in the internal DB 9 at any time according to an instruction from the company. Updated by DB server 11
(For example, addition, deletion, change, etc.). Internal DB9
Selects only data that may be disclosed to the outside from its own data, or changes the data to a format suitable for being disclosed to the outside, and provides the data to the external DB 3 .

The internal DB server 11 has a time register 15 for storing two predetermined times as TimeA and TimeB.
And TimeA and TimeB from the data of the internal DB 9
And a differential data extracting unit 17 for extracting data updated between the two times (hereinafter referred to as internal differential data). The internal difference DB 13 stores the extracted internal difference data.

The internal DB server 11 includes a data transmission unit 19 that transmits internal difference data and the like to the external DB server 5 using FTP (File Transfer Protocol) that can pass through the FW 1, and an external DB using FTP. A data acquisition unit 21 that acquires various data from the server 5. When the operation of transmitting the internal difference data is completed, the data transmitting unit 19
A transmission completion notification indicating the completion is created, and the transmission completion notification is provided to the external DB server 5. Data acquisition unit 21
Is to read various data registered on the FTP path in the external DB server 5 (indicating the directory where the FTP service that can pass through the FW is executed) in a leading manner (that is, the internal DB server 11 From the external DB server 5). Further, when the data acquisition operation is completed, the data acquisition unit 21 creates a reception completion notification indicating that the data acquisition operation is completed, and sends it to the data transmission unit 19. Data transmission unit 1
9 provides these completion notifications to the external DB server 5.

The external DB server 5 sets two predetermined times,
A time register 25 for storing as TimeC and TimeD, and a difference data extracting unit 27 for extracting data updated between two times of TimeC and TimeD (hereinafter referred to as external difference data) from data of the external DB 3; Having. The external difference DB 7 stores the extracted external difference data.

The external DB server 5 is an internal DB server 1
In order to enable the first to acquire external difference data and the like, the data registration unit 29 that registers the external difference data and the like in the FTP path, and the data that receives the internal difference data and the like transmitted from the data transmission unit 19 And a receiving unit 31. The data registration unit 29 waits until the data acquisition unit 21 acquires the external difference data or the like registered on the FTP path.

When the operation of extracting the external difference data is completed, the difference data extracting unit 27 creates an extraction completion notification indicating the completion of the operation and sends it to the data registration unit 29. In addition, when the operation of providing the received internal difference data to the external DB 3 is completed, the data receiving unit 31 creates an acquisition completion notification indicating the completion and sends the notification to the data registration unit 29.
The data registration unit 29 sets these completion notifications on the FTP path and waits until the data acquisition unit 21 acquires them.

Referring to FIG. 2, the internal DB server 11
A processing flow when transmitting the update data of the internal DB 9 to the DB server 5 will be described.

In the internal DB server 11, the extraction time interval of the internal difference data is predetermined.
When the time to extract the internal difference data from DB9 comes,
The arrival current time is set in TimeB of the time register 15 (S1). At TimeA, at the end of the previous extraction operation,
The previous extraction time has already been set. Next, the difference data extraction unit 17 performs the processing from TimeA to TimeB (that is,
Between the previous extraction time and the current extraction time)
The internal difference data updated in the DB 9 is extracted (S2) and stored in the internal difference DB 13.

The data transmission unit 19 extracts the internal difference data from the internal difference DB 13, and writes the internal difference data to the FTP path of the external DB server 5 using FTP (S3). When the transmission operation is completed, the data transmission unit 19 creates a transmission completion notification indicating that the transmission of the internal difference data is completed, and writes the notification to the FTP path of the external DB server 5 using FTP (S
Four).

In the external DB server 5, when the data receiving unit 31 detects that the transmission completion notification is present on its own FTP path (S11), it deletes the transmission completion notification from the FTP path (S12), Import the internal difference data
DB3 is updated (S13). If any error occurs in the internal differential data receiving operation at this time, the data receiving unit 31 does not delete the transmission completion notification from the FTP path.
(That is, leave it on the FTP path).

When the update of the external DB 3 is completed, the data receiving unit 31 deletes the internal difference data on the FTP path (S1).
4), create an acquisition completion notification indicating that the acquisition of the internal difference data is completed, and send it to the data registration unit 29. The data registration unit 29 registers the completion notice on the FTP path (S1
5) Wait until the acquisition completion notification is acquired from the data acquisition unit 21.

On the other hand, after the transmission of the internal difference data is completed, the internal DB server 11 monitors the FTP path of the external DB server 5. That is, the data acquisition unit 21 uses the FTP to periodically (for example, every minute) use the FTP of the external DB server 5.
By accessing the path, it is confirmed whether or not a file such as a notice of completion of import exists (S5). The data acquisition unit 21
As a result of the confirmation, if there is a capture completion notification (S6), the capture completion notification is obtained using FTP. Data acquisition unit 21
Acquires the notification of the completion of import,
It is determined that the provision of the internal difference data has been completed without delay (S7), and the time registered in TimeB of the time register 15 is registered in TimeA (S8). When the next internal differential data extraction time comes, the next extraction time
Registered in TimeB, each device repeats the same operation as above.

The data acquisition unit 21 stores the FT of the external DB server 5
If there is no fetch completion notification on the P path, it is next determined whether or not there is a transmission completion notification (S9). If there is no transmission completion notification, the data acquisition unit 21 determines that the update of the external DB 3 has not been completed yet, returns to step S5, and returns to the step S5.
Continue monitoring the FTP path. If there is a transmission completion notification, the data acquisition unit 21 determines that some error has occurred, and deletes the internal difference data on the FTP path (S10). In this case, the difference data extraction time is not updated, and the times set in TimeA and TimeB of the time register 15 are not changed. Therefore, at the next extraction time of the internal difference data, the previous extraction time is registered in TimeA and the next extraction time is registered in TimeB, and the difference data extraction unit 17 performs two cycles (normal internal extraction data). (The difference data extraction time interval is one cycle.)
9, the internal difference data updated in step 9 is extracted. Then, each device performs the above operation on the internal difference data for two cycles.

Next, referring to FIG. 3, the internal DB server 11
However, the processing flow when the update data of the external DB 3 is acquired from the external DB server 5 will be described.

In the external DB server 5, the extraction time interval of the external difference data is predetermined similarly to the internal difference data, and when the time to extract the external difference data from the external DB 3 comes, the current time that arrives is set to the time. It is set in TimeD of the register 25 (S21). In Time C, the previous extraction time is already set at the end of the previous extraction operation. The extraction time of the internal difference data and the extraction time of the external difference data may be the same time or different times.

Next, the difference data extracting unit 27 extracts the external difference data updated in the external DB 3 during the period from TimeC to TimeD (that is, between the previous extraction time and the current extraction time). (S22), send it to the data registration unit 29.
The data registration unit 29 stores the received external difference data in the external DB
Writing is performed on the FTP path of the server 5 (S23). When the extraction of the external difference data is completed, the difference data extraction unit 27
An extraction completion notice indicating that the extraction of the external difference data has been completed is created and sent to the data registration unit 29. Data registration unit 2
9 writes an extraction completion notice on the FTP path of the external DB server 5 (S24).

On the other hand, in the internal DB server 11, the data acquisition unit 21 periodically (for example, every minute) accesses the FTP path of the external DB server 5 to determine whether a file such as an extraction completion notification exists. Confirm. The data acquisition unit 21
As a result of the confirmation, when the presence of the extraction completion notification is detected (S3
1), the extraction completion notice on the FTP path of the external DB server 5 is deleted (S32). If any error occurs in the operation at this time, the data acquisition unit 21 does not delete the extraction completion notification from the FTP path (that is, the FT of the external DB server 5).
Leave it on the P pass).

Next, the data acquisition unit 21 acquires external difference data from the FTP path of the external DB server 5 using FTP, and updates the internal DB 9 (S33). Data acquisition unit 21
Deletes the external difference data on the FTP path of the external DB server 5 when the operation of acquiring the external difference data is completed (S
34). Then, the data acquisition unit 21 creates a reception completion notification indicating that the acquisition of the external difference data has been completed, sends the notification to the data transmission unit 19, and the data transmission unit 19 uses the FTP to transmit the FTP path of the external DB server 5. Write on top (S35).

On the other hand, in the external DB server 5, after extracting the external difference data, the data receiving unit 31 monitors for a certain period of time whether or not there is a reception completion notification on its own FTP path (S26).
However, the certain period to monitor means that the data acquisition unit 21
The period must be longer than one period for periodically accessing the FTP path of the external DB server 5 to obtain the difference data. When the data reception unit 31 detects the reception completion notification within the predetermined period, it determines that the provision of the external difference data from the external DB 3 to the internal DB 9 has been completed without delay (S2).
7) The time registered in TimeD of the time register 25 is
Register with TimeC (S28). When the next external difference data extraction time arrives, the time is registered in TimeD, and each device repeats the same operation as described above.

If the data receiving unit 31 does not detect the reception completion notification even after a certain period, the data receiving unit 31
It is determined whether or not there is an extraction completion notification on the FTP path (S29).
If the extraction completion notification is not on the FTP path, the data receiving unit 31 determines that the update of the internal DB 9 has not been completed yet, returns to step S25, and continues to monitor the reception completion notification.

The data receiving unit 31 is provided with the FT of the external DB server 5.
When there is an extraction completion notice on the P path, it is determined that some error has occurred, and the external difference data on the FTP path is deleted. In this case, the difference data extraction time is not updated, and the times registered in TimeC and TimeD of the time register 25 are not changed. Therefore, at the next extraction time of the external difference data, the previous extraction time is registered in TimeC and the next extraction time is registered in TimeD, and the difference data extraction unit 27 performs two periods (normal external extraction data). (Differential data extraction time interval is one cycle)
The external difference data updated in B3 is extracted. Then, each device may perform the above operation on the internal difference data for two cycles.

Although the preferred embodiment of the present invention has been described above, the above embodiment is an exemplification for describing the present invention, and is not intended to limit the scope of the present invention only to this embodiment. Without departing from the spirit of the invention, those skilled in the art
The present invention can be implemented in various other forms in which various modifications, improvements, modifications, simplifications, and the like are added to the above-described embodiment. For example, in the present embodiment, all the functions for processing the internal data and the external data are described as being in the internal DB server 11 and the external DB server 5, but it is not always necessary to do so. May be provided as one machine. Also, although the explanation was made using FTP for sending and receiving various data, instead of FTP, HTTP (Hyp
er TextTransfer Protocol) or SMTP (Simple
Mail Transfer Protocol) may be used.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a flow of processing for reflecting an update of an internal DB 9 on an external DB 3.

FIG. 3 is a diagram showing a flow of processing for reflecting an update of an external DB 3 in an internal DB 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Firewall (FW) 3 External database (external DB) 5 External database server (external DB server) 7 External differential database (external differential DB) 9 Internal database (internal DB) 11 Internal database server (internal DB server) 13 Internal differential Database (internal difference DB) 15 time register 17 difference data extraction unit 19 data transmission unit 21 data acquisition unit 25 time register 27 difference data extraction unit 29 data registration unit 31 data reception unit

Claims (10)

[Claims] 1. A system for synchronizing an internal database and an external database separated from each other by a firewall, comprising: an internal database server arranged inside the firewall; and an external database arranged outside the firewall. A data providing unit for providing the internal database updated in the internal database to the external database server, and the external data registered at a predetermined location outside a firewall. Take the initiative from inside the firewall,
A data acquisition unit that updates the internal database with the acquired external data, wherein the external database server receives the internal data provided by the data providing unit,
A database synchronization system comprising: a data receiving unit that updates the external database with the received internal data; and a data registration unit that registers the external data updated in the external database at a predetermined location outside the firewall. . 2. The internal database server according to claim 1, wherein the internal database server has an internal differential data extracting unit that extracts internal differential data updated during a predetermined period from the data of the internal database as the internal data. 2. The database synchronization system according to claim 1, wherein the server has an external difference data extraction unit that extracts, as the external data, external difference data updated during a predetermined period from the data of the external database. 3. The internal database server, wherein: an internal time storage means for storing a start of an update period in which the internal data is updated; and whether the external database has been updated by the updated internal data. External data storage means for storing the start of an update period in which the external data is updated, and whether or not the internal database has been updated with the updated external data. External data update confirming means for confirming whether or not the internal data update confirming means has confirmed that the external database has been updated, the internal time storage unit sets the start time of the internal data to And when the external data update confirmation means confirms that the internal database has been updated, Part time storage unit, a database synchronization system according to claim 1, wherein updating the start timing for the external data. 4. The external database server has means for creating an acquisition completion notification indicating that the external database has acquired the internal difference data, and registering the notification at a predetermined location outside the firewall. An internal data update confirmation unit of the server initiatively acquiring the acquisition completion notification, and confirming the update of the internal database based on whether or not the acquisition completion notification is acquired; and Creates a reception completion notice indicating that the external difference data has been received, has means for providing the external database server, the external data update confirmation means of the external database server acquires the reception completion notice, The confirmation of the update of the external database is performed based on whether or not the receipt completion notification has been acquired. 3. The database synchronization system according to 3. 5. A data extraction unit that is arranged in a firewall and extracts updated internal difference data from data of an internal database existing in the firewall, and an external device that exists outside the firewall. An internal database server, comprising: a data providing unit that provides the internal difference data to the database server. 6. An external device located outside the firewall, receiving internal difference data updated in the internal database sent from an internal database existing in the firewall, and externally present outside the firewall. An external database server that updates the external database by providing the internal difference data to a database. 7. A data extraction unit that is arranged outside a firewall and extracts updated external difference data from data of an external database existing outside the firewall, and An external database server, comprising: a data registration unit configured to register at a predetermined location outside the wall so that an internal database server existing in the firewall can initiatively acquire the external difference data. 8. An external difference data, which is arranged in a firewall and updated in an external database existing outside the firewall, and registered in a predetermined location outside the firewall, An internal database server that updates the internal database by initiatively acquiring it through a wall and providing it to an internal database present in the firewall. 9. A method for synchronizing an internal database and an external database separated from each other by a firewall, wherein an internal database server disposed in the firewall updates internal data updated in the internal database. Providing the internal data provided by the process of providing the internal data to the external database server disposed outside the firewall, and receiving the internal data provided by the process of providing the internal data. A step of updating a database; a step of the external database server registering external data updated in the external database at a predetermined location outside the firewall; and a step of the internal database server Climb to the place By the external data has, the led to obtain from within the firewall, database synchronization method and a process of updating the internal database by the acquired external data. 10. A process in which the internal database server extracts internal difference data updated within a predetermined period from the data of the internal database as the internal data; and 10. The database synchronization method according to claim 9, further comprising: extracting, as the external data, external difference data updated within a predetermined period from the data of the database.