JPH0728686A - Distributed database system - Google Patents

Abstract

(57) [Summary] [Purpose] Transfer data between different databases without making the user aware of the data format and character code conversion. [Constitution] Data conversion means for converting the attributes of the data read from its own database or the attributes of the data sent from another database into the instructed data attributes are provided. If the data attributes do not match, the data conversion unit converts the attributes to the same data attributes as the transfer destination, and then transfers the data read from within its own database to the transfer destination specified by the transfer request, or from another database. Store the received data in its own database.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows a plurality of databases having different data formats or code systems to be connected to a LAN,
The present invention relates to a distributed database system connected by a communication medium such as WAN.

[0002]

2. Description of the Related Art In computer systems, JI
There are a plurality of code systems such as S, ASCII, and ISO, and which system is to be adopted is basically determined by the hardware of the computer main body and the type of operating system, and cannot be freely selected by the user. It is generally specific to the computer hardware.

The data type, data model, and data format in the database are also peculiar to each DBMS (database management system), and once the DBMS to be used is decided, it cannot be changed by the user. Will end up.

Therefore, when the data stored in one computer system is to be transferred to another computer system, the user is not required to transfer the data to the same DBMS of the same operating system of the same model except for the character code and data type of the data. , The data model and data format must be converted and transferred according to the destination DBMS and its environment by some means.

In order to realize the purpose, there are many data transfer and data conversion programs, but in the worst case, the user himself / herself investigates the specifications such as the character code and data type of the DBMS of the transfer source and the transfer destination. A conversion program is created by using the conversion program, data conversion is performed using this conversion program, and data transfer to different types of DBMS is realized.

[0006]

However, what the data attributes such as the character code, the data type, the data model, and the data format are, does not need to be considered in the user's business processing. Therefore, there is a problem in that the data conversion work associated with the data transfer as described above imposes a heavy burden on the user and reduces the efficiency of business processing.

Further, a distributed data processing system in which a computer system is connected to a communication network and a plurality of systems mutually utilize their functions and data is becoming popular. In such a system, the above-mentioned data transfer is also accompanied. There is a problem that such a data conversion work is a heavy burden on the user.

An object of the present invention is to provide a distributed database system capable of transferring data to different databases without making the user aware of data attributes such as a code system and a data format.

[0009]

In order to achieve the above object, the present invention inputs a transfer request consisting of a database from which data is taken out, a data retrieval range, and information identifying a database to which the retrieved data is transferred. Input means, information storage means for storing data attribute definition information such as data formats and code systems stored in all databases in the system, and a plurality of database control devices provided corresponding to each database And each database controller,
Database access means for storing and reading data to and from the own database, and data for converting the attributes of the data read from the own database or the attributes of the data sent from another database into the specified data attributes The conversion means and the transfer request input by the input means are transmitted to the database control device corresponding to the database from which the data is taken out through the communication medium, and in response to the transfer request transmitted from another database control device. Control to start the database access means to read out the data in the retrieval range specified by the transfer request from the own database and store the data sent from another database in response to the transfer request sent by the own database in the own database. To control the Whether or not the data attribute of the transfer destination matches the data attribute of the transfer destination is determined by the data attribute definition information of the information storage means, and if they do not match, the data conversion means converts the attribute to the same data attribute as the transfer destination, and then The control means controls the transfer of the data read from the database to the transfer destination designated by the transfer request or the control of storing the data sent from another database in the own database.

Alternatively, each of the database control devices may be provided with a format of data stored in its own database,
Information storage means storing data attribute definition information such as a code system, database access means for storing and reading data to and from its own database, and the attribute of the data read from its own database to the designated data attribute. Data conversion means for converting, and information of the data attribute of the transfer destination database is added to the transfer request input by the input means, and is transmitted to the database control device corresponding to the database of the data extraction source through the communication medium, In response to the transfer request sent from another database control device, the database access means is activated, and the data in the retrieval range specified in the transfer request is read out from the own database and the transfer request sent by itself. Data sent from other databases The data attribute definition information of the information storage means and the transfer destination database sent by the transfer request are used to determine whether the data attribute of the extraction source and the data attribute of the transfer destination match. A control for determining by the information of the data attribute, and if the data does not match, the data converting means converts the attribute to the same data attribute as the transfer destination, and then transfers the data read from the own database to the transfer destination designated by the transfer request. And a control means for performing.

Alternatively, each of the database control devices may be provided with a format of data stored in its own database,
Information storage means for storing data attribute definition information such as a code system, database access means for storing and reading data to and from its own database, and data for which the attributes of data sent from another database are designated Data conversion means for converting into an attribute, and information of the data attribute of the transfer destination database is added to the transfer request input by the input means, and the data is sent to the database control device corresponding to the data extraction source database through the communication medium. At the same time, the database access means is activated in response to a transfer request transmitted from another database control device, the data in the retrieval range specified by the transfer request is read out from within the own database, and the read data contains the data attribute. Control and addition of information and transfer to the destination database In response to the transfer request sent by itself, control is performed to store the data sent from another database in its own database, and whether the data attribute of the extraction source matches the data attribute of the transfer destination It is judged by the data attribute definition information of the storage means and the data attribute information of the transfer source database sent together with the read data, and if they do not match, the data conversion means converts the attribute to the same data attribute as the transfer destination. , And control means for controlling the storage in its own database.

[0012]

According to the above means, when a transfer request including a database from which a data is extracted and a range to be extracted and a database to which the extracted data is transferred is input to any one of the database control devices,
The database control device transmits the input transfer request to the database control device corresponding to the database from which the data is taken out through the communication medium.

On the other hand, the database control device of the transfer source which has received the transfer request activates the database access means and reads out the data in the retrieval range designated by the transfer request from its own database. Then, whether or not the data attribute of the transfer source and the data attribute of the transfer destination match is determined by the data attribute definition information of the information storage means, and if they do not match, the data conversion means converts the attribute to the same attribute as the transfer destination. Then, the data is transferred to the transfer destination through the communication medium.

The database controller of the transfer destination stores the sent data in its own database. in this case,
When the attribute of the data sent from the transfer source does not match the attribute of the own database, the attribute is converted by the data conversion means and then stored in the own database.

Therefore, when data is transferred to a different database, it can be transferred without the user being aware of the data attributes such as the code system and the data format.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the most basic system configuration of the present invention.

The distributed database system of this embodiment includes database control devices 100a and 100b,
An input device 101 for inputting a data transfer request, and database groups 102a and 102b corresponding to the input devices 101,
All database groups 102a, 102b in the system
Control information file 10 that stores data attribute definition information such as the format and code system of the data stored in
3 and a work file 104 for data transfer.

Database control devices 100a and 10
0b is connected by the communication path 105. Further, the control information file 103 and the work file 104 can be arbitrarily accessed from the database control devices 100a and 100b.

Further, the database groups 102a, 102
b is a plurality of databases 102a1, 102a2, 102 having different data formats and code systems.
a3, 102b1, 102b2, 102b3.

Further, own database groups 102a, 10
2b databases 102a1, 102a2, 102
Database access units 106a and 106b for storing and reading data in and from a3, 102b1, 102b2, 102b3, and each database group 102
database management unit 107a that manages a and 102b,
107b.

Here, the database access unit 106a
And 106b are own database groups 102a, 102b.
b databases 102a1, 102a2, 102a
Database access unit 1 for storing and reading data in and from 3, 102b1, 102b2, 102b3
06a1, 106a2, 106a3 and 106b1,
It is composed of 106b2 and 106b3. Similarly, the database access units 106a and 106b are connected to the databases 102a1, 102a2, 102a3, 10b.
2b1, 102b2, 102b3 database management units 107a1, 107a2, 107a3 and 1
07b1, 107b2, 107b3.

Database control devices 100a and 10
0b is also the own database group 102a, 102b
Data conversion units 108a, 108b for converting the attributes of data read from the data system (code system, data format, data model) or the attributes of data sent from another database group into designated data attributes There is.

Further, the transfer request input by the input device 101 is transmitted to the database control device 100a or 100b corresponding to the database group of the data extraction source through the communication path 105, and is also transmitted from the other database control device 100b or 100a. The database access unit 106a or 106b is activated in response to the received transfer request, and control is performed to read out the data in the retrieval range specified in the transfer request from within the own database group, and other database groups in response to the transfer request transmitted by itself. 1
The data attribute definition of the control data file 103 is performed to control whether the data sent from the server 02b, 102a is stored in the own database 102a or 102b, and whether the data attribute of the extraction source and the data attribute of the transfer destination match. Judging by information, if there is a mismatch, data conversion unit 1
After converting the attribute to the same data attribute as the transfer destination in 08a,
The control for transferring the data read from the own database group 102a or 102b to the transfer destination designated by the transfer request and the data sent from the other database group 102b, 102a are made to the own database group 102a or 10
2b is provided with control units 109a and 109b for performing control.

Here, the database access unit 106a
And 106b, database management units 107a and 107
b, data conversion units 108a and 108b, control unit 109
a and 109b are configured by a dedicated program.
In addition, the database access units 106a and 106b
May be configured with only one function of reading or storing data.

On the other hand, the input device 101 is connected to either or both of the database control devices 100a and 100b via the man-machine interface program 110. In this embodiment, it is connected to the database control device 100b. In addition, this input device 1
01 is each database control device 100a and 100b
May be provided corresponding to each of the above.

FIG. 2 shows the attribute definition information of each database stored in the control information file 103. This attribute definition information includes the host environment name 201, the database name 202, the data model contents of the database,
It consists of a data format rule 203 such as a character code set and precision of numerical data.

In the data format rule 203 of FIG. 2, the value specified by the "DBtype" clause means the type of database, and in this example, RDB (relational database). This is the control unit 109
a and 109b indirectly connect to the data access units 106a and 1
It is used as information for selecting 06b.

The value specified in the "CharSet" clause indicates the character code system, and the information below the "DataModel" clause defines the data model and data format information.

The control information file 103 stores attribute definition information of all databases in the system in the above format.

In the above configuration, the user of the data transfer function inputs the database name of the transfer source, the database name of the transfer destination, and the data range from the input device 101 when transferring the data. The information input by the data transfer user is transferred from the man-machine interface program 110 to the control unit 109b of the transfer destination database control device 100b.
Be transmitted to.

Control unit 10 on the transfer destination side (export side)
9b writes the information input by the data transfer user in the control data file 103, and controls the control unit 1 on the transfer source side.
09a is requested to retrieve and transfer the data via the communication path 105. That is, a data transfer request is made.

The control unit 109 on the transfer source side that has received the transfer request
a performs processing in the sequence shown in FIG.

First, the control unit 109a on the transfer source side that has received the transfer request refers to the control data file 103 and sets the transfer source data set name, data name, data range, and transfer destination (import destination) database name. Input (step 602).

Next, the attribute definition information of FIG. 2 is searched using the transfer source database name as a key, and the database access section corresponding to the type of database defined in the data format rule 203 is selected. For example, the database access unit 106a1 is selected (steps 602 and 603).

Next, the database access unit 106
Using a1, data is read from the database 102a1 corresponding to the access unit 106a1. in this case,
The data in the range specified by the transfer request is read (step 605).

Next, using the transfer destination database name as a key, the attribute definition information of the transfer destination database is acquired from the control data file 103 (step 606) and compared with the attribute and format of the data read from the database 102a1. (Steps 607 and 608) If they are different, the data conversion unit 108a is activated (Step 609), attribute conversion such as data code and data format is performed (Step 610), and the converted data is communicated. It is transmitted to the transfer destination through the path 105 (step 611), and the transfer process is completed.

In addition to using the communication path 105, a method of transferring data through the work file 104 may be adopted.

Next, the processing on the transfer destination side (import side) will be described with reference to the flowchart of FIG.

The database control device 100b on the transfer destination side, which has received the data from the transfer source, controls the control data file 1
It is determined whether to perform character code / data format conversion using the attribute definition information of 03 (steps 702 to 7).
05), a database that stores the received data (10
2b1 to 102b3) and the data attribute of the received data are the same, the database access unit corresponding to the database (one of 102b1 to 102b3) specified by the transfer request is selected and activated.
For example, the database access unit 106b1 is activated. Then, the database access unit 106b1 stores the received data in the database 102b1 (steps 708 and 709).

However, if the data attributes are not the same, the data conversion unit 1108b converts the data attributes and then stores the received data in the database 102b1 (steps 706 to 709).

In this embodiment, data transfer to and from both the transfer source side and the transfer destination side is taken into consideration in consideration of data transfer with a plurality of transfer destinations including those which do not actually have the attribute conversion function in the transfer destination database control device. Although a conversion unit for converting attributes is provided, it is clear that either one may be used.

By the way, in the above-mentioned embodiment, the data attribute definition information of all the databases in the system is stored in advance in the control data file 103 common to the respective database control devices 100a and 100b, and the data attribute definition information is transferred by this attribute definition information. Although it is determined whether or not the conversion of the data attribute with respect to the request is necessary, the configuration may be as shown in the second embodiment of FIG.

That is, each database control device 100
The control data files 111a and 111b storing only the data attribute information of the database group 102a in its own device are provided in each of a and 100b, and the transfer is performed when the transfer request 112 is transmitted from the transfer destination database control device 100b. The control unit 109b adds the data attribute information 113 of the transfer destination database to the request 112, and transmits the request 112.
When sending the data read from the transfer source database to the transfer destination, check whether the data attribute of the read data and the data attribute of the transfer destination database are the same, and if they are not the same, the data conversion provided in the transfer source Part 108
The data attribute may be converted by a and transmitted to the hand-playing destination.

By doing so, a communication path for the common control data file 103 becomes unnecessary.

Further, as shown in still another embodiment of FIG. 6, the control data files 111a and 111 similar to those of FIG.
b is provided in each of the database control devices 100a and 100b, and when the data is transferred from the transfer source to the transfer destination, the data attribute information is added to the transfer data 114 as the control unit 109a.
Is added and transmitted, and the transfer destination side that received this data determines whether the received data and the data attribute of the database that stores this data are the same. The data conversion unit 108b may convert the data attribute and store it in the corresponding database.

Also in this case, the same effect as in FIG. 5 can be obtained.

Next, in the above embodiment, an example of transmitting and receiving data and a transfer request on a one-to-one basis between the database control devices has been shown. However, if a broadcast process as shown in the flowchart of FIG. It is possible to sequentially transfer data from one side to a plurality of transfer destinations and to sequentially receive transfer requests or data from a plurality of transfer destinations.

That is, assuming that there are N related database control devices, first, the variable n is set to n = 1, and data is transmitted to this database control device with n = 1 (steps 71 and 72). ). Next, the variable n is updated and the data is transmitted to the database control device with n = 2 (steps 74 and 72).

When this process is repeated and n = N (step 73), the transmission process is completed.

Next, in order to receive the transfer request or data, the variable n is set to n = 1, and the transfer request or data from this database controller of n = 1 is received (steps 75 and 76). Next, the variable n is updated, and a transfer request or data from the database controller with n = 2 is received (steps 78 and 76).

When this process is repeated and n = N (step 77), the receiving process is completed.

FIG. 8 is an explanatory diagram of a method for optimizing the data transfer amount. For example, the database control device 100a controls the database control device 100b to use the range 502 of the data distributed at the time of the previous data distribution as history information. It is stored in the data file 103, and when the next data is distributed, the history information is referred to so that only the differences 501 and 502 from the data distributed in the past are distributed.

In this way, the same data is not distributed in duplicate even if the broadcast process is performed, so that the data transfer amount can be minimized.

By the way, when data is transferred or distributed from a certain database control device to a plurality of other database control devices, the data transfer user has the data to be transferred, the range / condition of the data, and the data. Describe the conditions such as transfer time and transaction occurrence as a script, and use this as a control data file 1
If the control section 109a, 109b is configured to interpret and execute the script, the data transfer process can be automatically performed.

[0056]

As described above, the present invention provides the data conversion means for converting the attribute of the data read from the own database or the attribute of the data sent from another database into the designated data attribute. If the data attribute of the source and the data attribute of the transfer destination do not match, the data conversion means converts the attribute to the same data attribute as the transfer destination, and then transfers the data read from its own database as specified by the transfer request. By configuring the data to be transferred first or stored from another database to be stored in its own database, the user of the database system is freed from the work of converting data attributes such as data format and character code. , Easy data transfer, transfer and distribution between databases with different data attributes without considering data attributes It can be carried out.

As a result, it is possible to easily construct a distributed database system or a duplicate database system and collect and distribute data in those systems.
It is possible to concentrate only on the original work such as aggregation and calculation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of data attribute definition information.

FIG. 3 is a flowchart showing processing on the transfer source side.

FIG. 4 is a flowchart showing processing on the transfer destination side.

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is a block diagram showing still another embodiment of the present invention.

FIG. 7 is a flowchart showing a data transfer process by broadcasting.

FIG. 8 is an explanatory diagram of a method for optimizing a data transfer amount.

[Explanation of symbols]

100a, 100b ... Database control device, 101 ...
Input device, 102a, 102b ... Database group, 10
3 ... control data file, 105 ... communication path, 106a,
106b ... Data access unit, 108a, 108b ... Data conversion unit, 109a, 109b ... Control unit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiromichi Ishikawa 5030 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Incorporated company Hitachi Ltd. Software Development Division

Claims (3)

[Claims] 1. In a distributed database system in which a plurality of databases having different data formats or code systems are connected by a communication medium, from a database from which a data is extracted and a range to be extracted, and a database to which the extracted data is transferred is identified. Input means for inputting a transfer request consisting of:
An information storage unit that stores data attribute definition information such as data formats and code systems stored in all databases in the system, and a plurality of database control devices provided corresponding to each database, Each database control device is instructed by the database access means for storing and reading data in the own database and the attribute of the data read from the own database or the attribute of the data sent from another database. The data conversion means for converting the data attribute and the transfer request input by the input means are transmitted to the database control device corresponding to the database from which the data is taken out through the communication medium, and are also transmitted from another database control device. Database for different transport requests Control to start the access means and read the data in the fetch range specified by the transport request from within its own database, and control to store the data sent from another database in its own database in response to the transport request sent by itself. Further, whether or not the data attribute of the extraction source and the data attribute of the transfer destination match is determined by the data attribute definition information of the information storage means, and if they do not match, the data conversion means sets the attribute to the same as the transfer destination. A control means for controlling the transfer of the data read from the own database to the transfer destination specified by the transfer request after the conversion to the data attribute, or the control of storing the data sent from another database in the own database. A distributed database system characterized by being configured from. 2. In a distributed database system in which a plurality of databases having different data formats or code systems are connected by a communication medium, from a database from which a data is extracted and a range to be extracted, and a database which is a transfer destination of the extracted data is identified. Input means for inputting a transfer request consisting of:
Each database control device comprises a plurality of database control devices provided corresponding to each database, and each database control device stores an information storage means for storing data attribute definition information such as a format of data stored in its own database and a code system. Database access means for storing and reading data to and from the own database, data conversion means for converting the attributes of the data read from the own database into the designated data attributes, and the input means. Information on the data attribute of the transfer destination database is added to the transfer request and transmitted to the database control device corresponding to the database from which the data is taken out through the communication medium, and to the transfer request transmitted from another database control device. On the other hand, start the database access means Then, control is performed to read the data within the retrieval range specified in the transfer request from within its own database, and control for storing the data sent from another database in its own database in response to the transfer request sent by itself. Whether or not the data attribute of the extraction source and the data attribute of the transfer destination match is determined by the data attribute definition information of the information storage means and the information of the data attribute of the transfer destination database sent by the transfer request, and they do not match. In this case, the data conversion means is configured to include the control means for converting the attribute to the same data attribute as the transfer destination and then transferring the data read from the own database to the transfer destination designated by the transfer request. A distributed database system characterized by. 3. In a distributed database system in which a plurality of databases having different data formats or code systems are connected by a communication medium, information for identifying a source database from which data is to be retrieved and a retrieval range, and a database to which the retrieved data is transferred are identified. It consists of input means for inputting, and a plurality of database control devices provided corresponding to each database. Each database control device has data attribute definition information such as the format of the data stored in its own database and the code system. An information storage unit that stores the data, a database access unit that stores and reads data in and from its own database, and a data conversion unit that converts the attributes of the data sent from another database into the instructed data attributes. , To the input means The information of the data attribute of the transfer destination database is added to the input transfer request, and the transfer request is transmitted to the database control device corresponding to the database of the data extraction source through the communication medium, and transmitted from another database control device. The database access means is activated in response to an incoming transfer request, data in the fetch range specified by the transfer request is read out from within the own database, data attribute information is added to the read data, and the data is transferred to the transfer destination database. In response to the control request and the transfer request sent by itself, the data sent from another database is controlled to be stored in its own database, and whether the data attribute of the extraction source and the data attribute of the transfer destination match Transfers sent together with the data attribute definition information and read data of the information storage means It is determined by the information of the data attributes of the database of the database, and when they do not match, the data conversion means converts the attributes into the same data attributes as the transfer destination, and then stores the data in the own database. Characteristic distributed database system.