Replica system and method of producing a replica

• US 6,356,916 B1
• Filed: 07/02/1999
• Issued: 03/12/2002
• Est. Priority Date: 01/13/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ichikawa, Noriko, Yamada, Kouichi, Yamatari, Mitsuyoshi
• Primary Examiner(s): Alam, Hosain T.
• Assistant Examiner(s): TRUONG, CAM Y T
• Application Number:
  US09/346,925
• Time in Patent Office: 984 Days
• Field of Search: 709/230, 707/201-204, 714/2, 714/6, 714/12, 714/15, 714/16, 714/19, 714/20
• US Class Current: N/A
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A replica system and a method of producing a replica are provided for dealing with a database management system including both database programs and files. The system transmits and receives data between interfaces using a common data format, by including a replica manager which receives a replica instruction and determines an object to be read from a master database and an object to be written in a copy database, according to the replica instruction. By giving a command to the database management system, data associated with the object to be read is read from the database, and data format is converted into a standard data format. The received data is then converted to data format associated with the object to be written, and the converted data is finally stored in the copy database.

Claims

1. A replica system having:

a first database;

first data management means for managing the first database;

a second database;

second data management means for managing the second database; and

a replica controller for producing replicas of data between said first and second databases, said replica controller comprising;

replica management means for receiving a replica instruction, and, according to the replica instruction, determining an object to be read from one of said first and second databases and an object to be written in the one of said first and second databases from which the object is not read;

first interface means, giving a command to said first data management means when the object is to be read from said first database, for reading from said first database data associated with the object to be read, and converting format of the data read into a standardized data format specified in said system, and for, when the object is to be written into said first database, converting the format of data to be written into said first database from the standardized data format specified in said system into the data format associated with the object to be written into said first database, and writing the data in the converted format into said first database by giving a command to said first data management means; and

second interface means for, when the object is to be written into said second database, receiving data in the standardized data format from said first interface means, converting the format of the data into a data format associated with the object to be written into said second database, and writing the data in the converted format into said second database by giving a command to said second data management means, and, when the object is to be read from the second database, giving a command to said second data management means for reading from said second database data associated with said object to be read, and converting the format of the data read from said second database into the standardized data format specified in said system.

2. The replica system according to claim 1, wherein said replica management means has replica pattern storage means for storing replica pattern data with information concerning the object to be read and the object to be written.

3. The replica system according to claim 2, wherein the replica pattern data includes code conversion information.

4. The replica system according to claim 3, further comprising replica instruction storage means in which the replica instruction is stored, wherein said replica management means reads the replica instruction from said replica instruction storage means.

5. The replica system according to claim 4, wherein each of said first interface means and second interface means has an interchangeable interface driver.

6. The replica system according to claim 5, wherein said replica management means has first replica distribution management means for sending data to and receiving data from said first interface means, and has second replica distribution management means for sending data to and receiving data from said second interface means.

7. The replica system according to claim 6, wherein said first interface means and said first replica distribution management means are part of a first computer, and said second interface means and said second replica distribution management means are part of a second computer, said first computer and said second computer being connectable via a communication medium.

8. The replica system according to claim 7, wherein said first computer has first communication interface means for managing communication, and said second computer has second communication interface means for managing communication, whereby said first communication interface means may be connected to said second communication interface means in accordance with an instruction sent from said first replica distribution management means, and said second communication interface means may be connected to said first communication interface means in accordance with an instruction sent from said second replica distribution management means.

9. The replica system according to claim 8, wherein said first computer has first communication information storage means for storing communication information used for communication with said second computer, and said second computer has second communication information storage means for storing communication information used for communication with said first computer.

10. The replica system according to claim 9, wherein the communication information is a communication address.

11. A method of producing a replica in a system having a first database managed by first data management means and a second database managed by second data management means, the method comprising:

receiving a replica instruction;

determining, according to the replica instruction, an object to be read from one of said first and second databases and an object to be written into the one of said first and second databases from which the object is not read;

reading from one of said first and second databases data associated with the object to be read, by giving a command to the one of said first and second data management means associated with the one of said first and second databases from which the object is to be read;

converting the data read from one of said first and second databases into a standardized data format specified in said system;

converting the data in the standardized data format into data in a format associated with the object to be written in the one of said first and second databases from which the object was not read; and

writing the data in the format associated with the object to be written into the one of said first and second databases from which the object was not read, by giving a command to the one of said first and second data management means into which the object is written.