JPH06259309A - Distributed data management system and data access method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate the management of the data retrieved from the shared database. [Structure] Index information about specific data in a shared database and storage presence / absence information in a local database 10A are stored in a schema database 10, and a data extraction destination is locally set based on a search result of the schema database. The control unit 10B determines whether the database 10A or the shared databases 30A to 30C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reorganizes data stored in a shared database distributed over a computer network and data stored in a local database according to a classification system of a user and uses it efficiently. And a data access method therefor.

[0002]

2. Description of the Related Art In the conventional method of using a distributed database, an inquiry sentence is sent from a terminal to each database and the response results are merged (combined) at the terminal. When the query is received, the database uses a schema, which is a framework of data, and replies that satisfies the condition among all the data included in the framework. Even if the above inquiry text is sent on the terminal side, what is returned as a reply result is unknown until the result arrives. Therefore, the distributed database is effective for retrieving related data by using a keyword etc. when it is not known what data is stored in the database. However, there is a demand for re-editing data from the perspective of individual data, such as wanting to reuse the data once seen on the terminal side, or interpreting and saving the data from its own perspective. Cannot be answered on the database side. Therefore, in order to perform data reclassification from the user's point of view using the conventional known method,
Store the search results in a local database and process the data, or prepare a large number of inquiries in advance, inquire from the terminal to multiple databases, retrieve the characteristic data from the multiple databases one by one, and the terminal side Had to join in.

[0003]

When the user tries to re-edit individual data from his own point of view and copies the data in a plurality of shared databases to the local database on the terminal side, the data is accumulated in the local database. The amount of data to be processed becomes huge. Also, once the data is copied, there is no way to know when the original data has been updated. Therefore, there is a problem that the consistency of data is lost.

On the other hand, when individual data is specified by combining various inquiries and the data is retrieved from the database and the retrieved data is re-edited, it is not intended by the user depending on the method of inquiring such as giving a keyword. It is difficult to directly indicate the data intended by the user, because a large amount of data is returned or data is missing.

As described above, when the data of the database distributed over the network is re-edited on the terminal side at the level of individual data, there is a problem that it is not always intended by the user.

Therefore, a first object of the present invention is to provide a distributed data management system capable of managing local data taken in from a shared database with a schema structure desired by a user.

A second object of the present invention is, in addition to the first object, is to provide a data access method of a distributed data management system capable of simplifying access to a shared database.

[0008]

In order to achieve the first object, the invention of claim 1 relates to the above-mentioned data in a distributed data management system in which a part of the data in the shared database is stored in a local database. A schema database that stores index information and attribute information indicating whether or not to be stored in the local database and classification information indicating the contents of a predetermined classification item as schema data; It is characterized by comprising a search means for performing a search based on the search result, and a control means for defining the search target as the local database when the attribute information of the schema data obtained as a result of the search indicates that there is accumulation in the local database. .

In order to achieve the second object, the invention of claim 2 is a data access method for a distributed data management system, wherein a part of data in a shared database is stored in a local database. A pointer database for accumulating pointer information indicating a storage address of the database; attribute information indicating whether the data is accumulated in the local database or in the pointer database in the form of the pointer information; A schema database in which the classification information indicating the classification contents and the index information indicating the item contents of the data are accumulated as schema data is provided in advance, and the schema database is searched by the classification information to obtain the search result. At least index of schema data Displaying the index information and pointing to the data to be searched by selecting the index information to be displayed, and accessing the local database based on the attribute information in the schema data corresponding to the selected index information, or It is characterized in that whether to access the shared database is determined, and when the attribute information indicates the shared database as an access destination, the pointer information on the pointer database corresponding to the attribute information is acquired.

[0010]

According to the invention of claim 1, in order to perform a classification item (keyword) search according to a schema structure desired by a user, index information is provided for data on the shared database and attribute information indicating whether or not the data is stored in the local database. Since the schema data is configured, the data existing on the local database can be known from the data obtained as a result of the schema search.

According to the second aspect of the present invention, since the storage address of the data on the shared database can be known in relation to the search of the schema database, the data can be read directly from the shared database by designating the address, as in the conventional case. Eliminates the need for keyword searches on shared databases.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an example of a system configuration of a data management system to which the present invention is applied.

In FIG. 1, the following devices are connected to a LAN (local area network).

Terminal 10: The terminal 10 communicates with the host computer 20, and the shared database 30A ...
The desired data on 30C (hereinafter referred to as shared data) is received. The terminal 10 stores the specific data itself in the received shared data in the local database 10A. Alternatively, information indicating the storage address of the specific data on the shared database (hereinafter referred to as a pointer) can be stored in the pointer base 10F. Terminal 10
The internal structure of will be described later.

Host computer 20: A shared database management unit 20A is provided inside, and the shared database management unit 20A accesses the shared databases 30A to 30C to register and retrieve data. Further, the shared database management unit 20A has two search functions: a keyword search and reading of data on a database of designated points. These functions are realized by a known software program.

The shared database management unit 20A has a database table shown in FIG. 3 and a host table shown in FIG. The database table of FIG. 3 shows the correspondence between the name of the database and the host where the database is stored. The host table of FIG. 4 describes the correspondence between host names and network real addresses. The shared database management unit 20A manages the accumulated data in the shared databases 30A to 30C using these tables (see FIG. 2).

Shared databases 30A to 30C: Stored in a file storage device with a predetermined structure.

Next, the internal structure of the terminal 10 will be described. The terminal 10 mainly includes a control unit 10B, an input unit 10C, and an output unit 1
0D, a local database 10A, a schema database 10E, and a pointer database 10F. An arithmetic processor such as a microcomputer is used for the control unit 10B, and the control unit 10B executes data management, data registration in various databases, and retrieval by executing the control procedure of FIGS. 9 to 12. Further, the control unit 10B has a function of requesting a search to the host computer 20 as in the conventional case. An information input device such as a keyboard or a mouse is used as the input unit 10C, and an operation instruction to the control unit 10B is input. A display device is used as the output unit 10D, and information related to the data search is displayed according to an instruction from the control unit 10B.

The local database 10A, the schema database 10E, and the pointer database 10F are formed on a floppy disk or hard disk. FIG. 5 shows an example of local data forming the local database 10A. Local data includes date, author, newsgroup (N
G) (abbreviated as G), title, and main text. The local database 10A is the input unit 10C.
Based on the keywords related to the above items entered from
It is possible to search for specific local data by the control unit 10B.

2 constituting the pointer database 10F
Seed pointer data is shown in FIGS. FIG. 6 shows the structure of pointer data including a logical address. In the example of FIG. 6, information regarding the date, author, NG, and title is included in the pointer data as index information. As information corresponding to the item of the text, instead of the actual text information (see FIG. 5), the database name in which this text information is stored and the address information of the text information in the data group of this database name, that is, the logical address is It is included in the point data.

FIG. 7 shows the structure of the Pont data including the real address. Similar to FIG. 6, the example of FIG. 7 also includes index information for each item, a real address in the body item, that is, the address of a database having body information, the network address of the host computer that manages this database, and It has the address of the text information.

Upon receiving either of the above two types of address information from the terminal 10, the host computer 20 extracts the text information addressed by the shared database management unit 20A from the designated shared database.

The schema data constituting the schema database 10E is stored in the local database 10A or the pointer database together with the above-mentioned index information, the classification information regarding the large classification, the middle classification and the small classification, and the data related to the text information. Attribute information indicating whether or not The classification information is classified into a large classification, a middle classification, which forms a tree-like classification structure as shown in FIG.
The contents of the minor category items are shown. The schema database can be searched by this classification information.

The local data management method and local data retrieval method implemented in the above configuration will be described with reference to FIGS.
This will be described with reference to FIG.

In accordance with an instruction from the input section 10C of the terminal 10, the host computer 20 searches the shared database as in the conventional case. The search result is returned to the terminal 10,
The output unit 10D is temporarily stored in the control unit 10B.
It is supposed to be displayed in.

The user sees this display and issues an instruction to save the relevant data (the text itself or the storage address of the text) for the necessary search result from the input unit 10C. In response to this instruction, the control procedure of FIG. 9 is activated by the control unit 10B. Next, the user gives an instruction from the input unit 10C as to the contents of the related data, that is, the body data or the storage address (in other words, which of the local database 10A and the pointer database 10F is to be the storage destination of the related data) ( 9 (S10).

When the local database 10A is instructed, the control unit 10B accepts the input of index information from the input unit 10C by the user, and creates local data including the text information (search result of the shared database) and the index information. (S20 → S30 in FIG. 9). The control unit 10B stores the created local data in the local database 10A.
Is cumulatively registered to update the local database 10A (S35 in FIG. 9).

When the user designates the pointer database, the control unit 10B stores the index information input from the input unit 10C and the address information (real address or logical address) included in the search result of the shared database. And pointer data is created and registered in the pointer database 10F (S20 → S in FIG. 9).
40 → S45).

When the local data or the pointer data is registered in the corresponding database by the above processing procedure, the control unit 10B displays the schema structure shown in FIG. 8 on the output unit 10D. Subsequently, the control unit 10B receives the user's input of the classification information, creates schema data from the classification information index information, the classification information, and the attribute information indicating the storage destination of the data related information, and registers the schema data in the schema database 10E (FIG. 9 S50).

When performing a data search, the user causes the control unit 10B to execute the control procedure shown in FIG. 10 according to an instruction from the input unit 10C. In response to this instruction, the control unit 10A displays the schema structure of FIG. 8 on the output unit 10D, and accepts the user's input of classification items from the input unit 10C (S100 of FIG. 10). For example, when the user designates "Computer" in the middle category, the control unit 10B searches the schema database 10E and extracts the schema data having the keyword "Computer". The extracted schema data is sequentially displayed on the output unit 10D. The user
When the user confirms that the desired data is present by looking at this display, the desired data being displayed is designated by the input unit 10C (S110 in FIG. 10). In response to this instruction, the control unit 1
0B determines whether the search target is the local database 10A or the pointer database 10F based on the attribute information in the schema data indicated by the instruction.

When the search target is the local database 10A, the control unit 10B executes a keyword search on the local database 10A based on the index information of the schema data, and extracts the local data having the same index information, It is displayed on the output unit 10D (S125 → S140 in FIG. 10).

On the other hand, the search target is the pointer database 1.
In the case of 0F, the control unit 10B executes a keyword search for the pointer database 10F based on the index information included in the selected schema data. When the pointer data having the same index information is extracted, the control unit 10B determines whether the address information held by the pointer data is a real address or a logical address, and creates a search inquiry according to the address format (S130 in FIG. 10). This search inquiry is sent from the terminal 10 to the host computer 20. The host computer 20 reads the shared data specified by the address information included in the search inquiry from the shared databases 30A to 30C, and the terminal 10
To (S135 in FIG. 10).

The data extracted from the local database or the shared database as described above is processed in step S.
It is displayed on the output unit 10D at 140, and the control procedure of FIG. 10 ends.

The search procedure executed by the shared database management unit 20A of the host computer 20 is well known, but will be briefly described because it is relevant to the present invention.

FIG. 11 shows the procedure for searching shared data when the pointer data is a logical address.

In step S200, the shared database management unit 20A checks whether the database name of the logical address exists in the database table of the shared database management unit. If the database does not exist, the search fails and error handling is done. If it exists in the database, the network address of the host having the database (the host computer 20 also serves as the host in the example of FIG. 1 of this embodiment) is searched for in step S210. Next, in step S220, the shared database management unit 20A
Is the shared database management unit 20A for that host.
If it is possible, you can check whether it is possible to access it directly or not, and if not, you can ask the shared database management section of the network where the host exists to continue processing. If possible, request processing, and if not possible, the search ends in failure. In step S240, the shared database management unit 20A checks whether the user has the access right to the database, and if the user has the right, searches the data.

FIG. 12 shows a procedure for searching shared data when the pointer data is a real address. First step S
In 300, the shared data management unit 20A checks whether or not the designated host can be directly accessed, and if it is accessible, can the shared data management unit 20A request processing to the shared database management unit of the network to which the host belongs, if not. Is checked in step S310, and processing is requested in step S315. Next, in step S320, it is checked whether or not the specified host has the required database.
If the database exists, the shared database management unit 2
0A checks in step S330 whether or not the user has the right to access the database, and if the user has the right, the data is searched in step S340.

As described above, in the present embodiment, not only the database is constructed with the schema structure created by the user, but also the schema database 10E is used to make the local database 10A and the shared databases 30A to 30A.
It becomes possible to access any of the Cs.

Therefore, it is not necessary for the user to create a search keyword for the acquired data in each subsequent data search. Further, since only important data is stored in the local database 10A, the local database 10A does not have a large capacity.

In addition to this embodiment, the following example can be carried out.

1) In this embodiment, a local database, a schema database, etc. are provided in the terminal 10, but they may be directly connected to the LAN. Also, a plurality of L
It can also handle shared databases connected to the AN. An example of the system configuration in such a case is shown in FIG.

2) In the present embodiment, an example is shown in which the data or related information extracted from the shared database is stored in the terminal 10, but the number of storage targets can be increased.

For example, the host computer 20 of FIG.
The network service or the like that provides information service to the terminal 10 and then accumulates in the shared databases 30A to 30C can be a storage target of the terminal 10. In addition, it is possible to register the data input from the input unit 10C of FIG. 1 in the local database 10A and the schema database 10E and search the local database by the schema database 10E.

3) In this embodiment, the local database 10
A. The search for the pointer database 10F is executed on the index information indicated by the schema data. However, if the addresses of the local data and the pointer data are added to the schema data, the control unit 10B directly reads the data by this address. It becomes possible to read.

4) In this embodiment, when the user selects the pointer database 10F by displaying the search result of the schema database 10E, the control unit 10B automatically executes a search request for the shared databases 30A to 30C. It is also possible to make a request for searching the shared database separately, while displaying the search result of.

[0047]

As described above, according to the present invention, by using the schema database, the user can manage the data in a desired logical structure and can easily access the local database or the shared database. It will be possible.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing the mutually related contents of various databases.

FIG. 3 is an explanatory diagram showing a table in which a database name and a host name for managing the database name are described.

FIG. 4 is an explanatory diagram showing a table in which host names and network addresses are described.

FIG. 5 is an explanatory diagram showing the contents of local data.

FIG. 6 is an explanatory diagram showing a structure of pointer data.

FIG. 7 is an explanatory diagram showing another structure of pointer data.

FIG. 8 is an explanatory diagram showing the structure of schema data.

9 is a flowchart showing a procedure executed by a control unit 10B of FIG.

10 is a flowchart showing a procedure executed by a control unit 10B of FIG.

11 is a flowchart showing a procedure executed by a control unit 10B of FIG.

12 is a flowchart showing a procedure executed by a control unit 10B of FIG.

FIG. 13 is a block diagram showing another system configuration.

[Explanation of symbols]

 10 terminal 10A local database 10B control unit 10C input unit 10D output unit 10E schema database 10F pointer database 20 host computer 20A shared database management unit 30A, 30B, 30C shared database

Claims (2)

[Claims] 1. In a distributed data management system for storing a part of data in a shared database in a local database, index information regarding the data, attribute information indicating whether or not the data is stored in the local database, and a predetermined classification. A schema database that stores classification information indicating the contents of items as schema data, a search unit that searches the schema database based on the classification items, and attribute information of schema data obtained as a result of the search. Indicates that there is accumulation in the local database,
A distributed data management system, comprising: a control means for defining a search target as the local database. 2. A data access method of a distributed data management system for storing a part of data in a shared database in a local database, wherein a pointer for storing pointer information indicating a storage address of the data in the shared database. A database and whether the data is stored in the local database,
A schema database in which attribute information indicating whether the pointer database has been stored in the form of the pointer information, classification information indicating classification contents of the data, and index information indicating item contents of the data as schema data is stored. Provided in advance, the schema database is searched by the classification information, at least the index information of the schema data obtained as the search result is displayed, and the search target data is designated by selecting the displayed index information, When it is determined whether to access the local database or the shared database based on the attribute information in the schema data corresponding to the selected index information, and the attribute information indicates the shared database as the access destination. In the genus Data access method of distributed data management system and acquires the pointer information on the pointer database corresponding to the information.