JP2001005704A - System and method for database access and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the efficiency of data access and to simplify a program by generating a data table of unique keys permitting direct access to data that an application requires on a database. SOLUTION: A database management system 5 controls and accesses the database 4 stored with data. A stored procedure executing means 6 executes a stored procedure registered in the database management system 5 and generates the data table of unique keys defined in the stored procedure. A database access request means 7 requests the database management system 5 to access the database 4 by using the data table of unique keys as the execution result of the stored procedure executing means 6 and receives the request result from the database management system 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database access method, method, and storage medium for accessing a database using a database management system, and more particularly to accessing a database using a stored procedure registered in the database management system. The present invention relates to a database access method, a method, and a storage medium.

[0002]

2. Description of the Related Art In a relational database management system (hereinafter abbreviated as RDBMS), which is one of database management systems, a relational database (hereinafter abbreviated as RDB) is managed in a table format. The table includes a base table in which data is actually stored and a virtual table (also called a view) generated from data of the base table which is not stored but is executed at the time of execution. Application refers to table SQ
The required data on the RDB is acquired via the RDBMS using the L language.

A client / server system (hereinafter C)
/ S system), the server has an RDB
Is connected, and an RDBMS is provided, and an application existing on the client side makes an RDB access request to the RDBMS using the SQL language, and receives an access result from the RDBMS.

That is, when a client application searches for necessary data, the application uses a search condition expression conforming to the SQL language format to the RD of the server.
The data is issued to the BMS, the RDBMS searches the data in the RDB, selects data that matches the given search condition, and returns the search result to the client application. At this time, in the RDBMS, a high-speed access technique such as creation of a search index is used.

However, an index created by an RDBMS is not always created in a form that is optimal for an application.

For example, in an RDB composed of a base table A and a base table B as shown in FIGS. 10A and 10B, consider an application for finding the latest price for each product.

The application performs the following processing. (1) In the base table B, a row including the latest product with the latest date and time among the same product numbers is selected. (2) The base table A and the result of the above (1) are related by respective product numbers. (3) A table including a product number, a product name, and a price is generated based on the association in (2). (4) Accessing the table resulting from the above (3), and acquiring data of the product number, the product name, and the price.

[0008] In this case, an index of the date and time is created in the RDBMS, but an index for the latest product with the same date and time is not created. For this reason, the application must describe in (1) the processing procedure for selecting the latest product with the latest date and time among the same product numbers. Thus, the indexes created by the RDBMS are not optimal for individual applications.

Further, since the above-described application processing is executed by each client, request information from each client and result information from the server frequently flow between the server and the client via the network.

[0010]

In the conventional technique described above, the index created by the RDBMS is a simple index of a data item, and the data particularly required on the application side is not in the index format, and the creation of the application is difficult. There is a problem that it becomes complicated. In addition, there is also a problem that traffic between the RDBMS and the application increases.

An object of the present invention is to provide means for creating a necessary index for each application by using a stored procedure registered in an RDBMS, simplifying application creation, and improving the performance of the entire system. .

[0012]

According to a first aspect of the present invention, there is provided a database access system which stores a database for storing data, receives a request from a database access requesting unit, accesses the database, and sends an access result to the database access request. Means for executing a stored procedure included in the database management system, creating a table of unique keys defined in the stored procedure, and a unique key created by the stored procedure execution means. A database access request unit for making a request to the database management system to access the database with reference to a table.

According to a second aspect of the present invention, there is provided a database access method in a client server system in which a server and a client are connected via a network, wherein the server stores and accumulates data and comprises one or more base tables. A relational database management system that accesses the relational database based on processing requested by an application and returns a processing result to the application; and a stored procedure that defines a virtual table associated with the base table and creates a table of a unique key. And a stored procedure starting means for starting the stored procedure, wherein the client issues a request for accessing the relational database by designating a virtual table defined by the stored procedure to the relational database management system. The results comprises an application received from the relational database management system.

The database access method according to a third aspect of the present invention is the database access method according to the second aspect, wherein the stored procedure starting means is configured to execute the stored procedure when the stored procedure has already been started and thereafter the relational database has not been updated. The stored procedure is not started.

The database access method according to a fourth aspect of the present invention is characterized in that, in the second aspect, the virtual table defined by the stored procedure functions as an index when an application accesses the relational database. .

A database access method according to a fifth aspect of the present invention is a method for accessing a database in a client server system in which a server and a client are connected via a network, wherein an application is defined by a base table and a stored procedure. A relation table with the virtual table being defined, and make an access request to the relation database to the relation database management system. The relation database management system analyzes the access request from the application, and the stored procedure generates the definition. When a virtual table is specified, the stored procedure is started and executed to generate a virtual table defined in the stored procedure, and an access request of an application using the virtual table is processed and processed by the application. The return, the application is characterized by receiving a processing result from the relational database management system.

According to a sixth aspect of the present invention, in the database access method according to the fifth aspect, the stored procedure uses a latest history unique key from a base table of basic data and two or more base tables holding its history. This is a process for generating a virtual table consisting of:

According to a seventh aspect of the present invention, there is provided a recording medium in which an application defines a table in which a base table and a virtual table defined by a stored procedure are associated with each other and issues an access request to a relational database to a relational database management system. Request processing, the relational database management system analyzes an access request from the application, and a stored procedure start processing for starting the stored procedure when a virtual table defined and generated by the stored procedure is specified; A virtual table generation process for executing a procedure to generate a virtual table defined in a stored procedure; an access process for processing an application access request using the virtual table and returning a processing result to the application; And characterized by recording a program for executing a data receiving processing of receiving a processing result from the relational database management system, to a computer.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A database access method according to the present invention will be described with reference to FIG.

Referring to FIG. 1, the database access method of the present invention comprises a database 4, a database management system 5, a stored procedure execution means 6, and a database access request means 7.

The database 4 is a database for storing data.

The database management system 5 manages the database 4, accesses the database 4 based on a request from the database access request unit 7, and returns an access result to the database access request unit 7.

The stored procedure execution means 6 executes a stored procedure registered in the database management system 5. The stored procedure includes a process of creating a table (index) of a unique key used by the database access request unit 7.

The database access request unit 7 requests the database management system 5 to execute the stored procedure execution unit 6 and access the database 4 using the execution result, and receives the request result from the database management system 5.

The operation of the present invention will be described. The stored procedure used by the database access request unit 7 is assumed to be registered in the database management system 5 in a known manner in advance.

First, the database access request means 7 sends an access request to the database 4 to the database management system 5 by specifying a table (index) of a unique key created by the stored procedure.

The database management system 5 executes the specified stored procedure by using the stored procedure execution means 6 to create a unique key table (index) used by the database access request means 7 and then executes the specified access request processing. And returns a processing result to the database access requesting means 7.

The database access request means 7 receives the processing result from the database management system 5.

As described above, the database management system 5
By creating a table (index) of the unique key used by the database access requesting means 7 in the stored procedure registered in the database 4, the database access requesting means 7 can obtain the required data from the database 4 at high speed.

An embodiment of the present invention to which the database access method of the present invention is applied will be described.

The first embodiment of the present invention will be described in detail with reference to the drawings. The first embodiment relates to a system that searches an RDB that manages the latest price of a product composed of two base tables to acquire and process the latest price of the product.

FIG. 2 is a diagram showing the configuration of the first embodiment.

Referring to FIG. 2, the first embodiment is similar to the first embodiment.
A server 1 and a client 2 are connected by a network 3. The server 1 connects the RDB 11 and the RDBMS
12 are provided. The RDBMS 12 includes a stored procedure 13 and a stored procedure starting unit 14. The client 2 includes an application 21.

The RDB 11 is a relational database for storing data and is composed of a base table A111 and a base table B112. Base table A111 is the basic data and base table B1
Numeral 12 holds the history of the basic data.

The real table A111 is one of the tables constituting the RDB 11. FIG. 3A shows the configuration of the base table A111. The base table A111 includes a product number and a product name,
Each line is uniquely distinguished by the product number which is the primary key.

The real table B 112 is one of the tables constituting the RDB 11. FIG. 3B shows the configuration of the base table B112. The base table B112 includes a product number, a date and time, and a price, and indicates the latest price of the product. Each time the price of a product is changed, a line indicating the changed date and time and a new price is registered. The product number corresponds to the product number in the base table A111, whereby the base table A111 and the base table B112 are associated with each other. The date and time is the date and time when the price is registered, and indicates the order of registration of the price within the same product number. A serial number may be used instead of the date and time. Each line is uniquely identified by a concatenation of a product number and a date and time (hereinafter, referred to as “product number + date time”).

The RDBMS 12 manages and accesses the RDB 11. The request issued from the application 21 is processed, and a processing result corresponding to the issued request is returned to the application 21.

The stored procedure 13 has a base table A11
A virtual table A131 is defined and generated based on the base table 1 and the real table B112, and a data set is selected and created. The stored procedure 13 is started by the stored procedure starting means 14. The name of the virtual table A131 is determined when the stored procedure 13 is registered in the RDBMS 12. By specifying this name, the application 21 specifies the virtual table A1 generated by the stored procedure 13.
31 can be referred to. The method for registering the stored procedure 13 in the RDBMS 12 is as follows.
According to a known method.

The virtual table A 131 is a virtual table including the latest history unique key. The stored procedure 13 generates a definition based on the base table A111 and the base table B112, and generates the base table A1.
A selection condition for combining the product number of No. 11 with the latest (maximum) date and time in the product number of the base table B112 corresponding thereto is specified. FIG. 3C shows the configuration of the virtual table A131.
Shown in The virtual table A131 includes a product number and a date and time. The product number corresponds to the product number in the real table A111, and the date and time correspond to the latest (maximum) date and time in the same product number in the real table B112. I have. The virtual table A 131 always serves as an index reflecting the latest state of the RDB 11 from the viewpoint of the application 21, and is referred to by the application 21.

The stored procedure activating means 14 activates the stored procedure 13 when the application 21 requests the RDBMS 12 to use the virtual table A 131 generated by the stored procedure 13.
If the specified stored procedure 13 has already been started and executed and the RDB 11 has not been updated thereafter, the stored procedure 13 is not started.
In this case, the processing result of the stored procedure 13 already executed is used.

The application 21 executes the stored procedure 13 to obtain the latest data of the RDB 11.
Defines the virtual table B211 associated with the virtual table A131 defined and generated, and issues an access request to the RDBMS 12. The processing result corresponding to the issued request is RDBM
Data processing is performed based on the data returned from S12.

The virtual table B211 is a virtual table defined and generated by the application 21 based on the virtual table A131, the real table A111, and the real table B112, and includes data required by the application 21. FIG. 3 shows the configuration of virtual table B211.
(D). The virtual table B211 includes a product number, a product name, and a price. The product number is the product number of the real table A111 corresponding to the product number of the virtual table A131, and the product name is the real table A111 corresponding to the product number of the virtual table A131. And the price is "Product number + date time" in virtual table A131.
Respectively correspond to the prices of the base table B112 corresponding to.

The operation of the first embodiment of the present invention will be described in detail with reference to FIGS.

4A and 4B are diagrams for explaining the operation of the first embodiment. FIG. 4A shows a specific example of the real table A111, FIG. 4B shows a specific example of the real table B112, and FIG. (D) shows a specific example of the virtual table B211. From (a) and (b), the latest price of the product name "Oh" is set to the date and time "05261800".
190 ". FIG. 5 is a diagram showing a flow of the operation of the first embodiment.

Referring to FIG. 5, the application 21
Relates the product number of the real table A111 to the product number of the virtual table A131, correlates the “product number + date time” of the real table B112 with the “product number + date time” of the virtual table A131, Virtual table B consisting of a product name and a price
Define 211 and set access to RDB11 to RD
A request is made to the BMS 12 (steps A11 to A12).

The RDBMS 12 is an application 21
Is analyzed (step M11), and when the virtual table A131 defined and generated by the stored procedure 13 is designated, it is determined whether or not the stored procedure 13 needs to be started and executed. When it is recognized that the procedure 13 needs to be activated, the stored procedure 13 is activated (steps M12 to M14). If the specified stored procedure 13 has already been started and executed and the RDB 11 has not been updated thereafter, the stored procedure 13 is not started. In this case, the processing result of the stored procedure 13 already executed is used.

The started stored procedure 13 executes the following processing. (1) For each product number in the base table B112, select a row including the latest date and time within the same product number (step S11). (2) The merchandise number in the base table A111 is associated with the merchandise number as a result of the above (1) (step S12). (3) A data set of the virtual table A131 including the product number of the real table A111 and the date and time of the result of the above (1) is created (step S13). The output result of the stored procedure 13 is shown in FIG.

Subsequently, the RDBMS 12 stores the virtual table B 211
(Step M15). RDBMS1
The processing result of No. 2 is shown in FIG.

After that, the RDBMS 12 returns a processing result to the application 21 (Step M16).

The application 21 is provided by the RDBMS 12
And performs application processing (step A13).

In this way, the application 21
By using the virtual table A131, which is the output result of the stored procedure 13, instead of an index,
The latest data of the required RDB 11 can be obtained at high speed.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings. The second embodiment relates to a system that retrieves an RDB that manages the contents of a failure of a product composed of three base tables to acquire and process the latest failure contents of the product.

FIG. 6 is a diagram showing the configuration of the second embodiment.

Referring to FIG. 6, the second embodiment is similar to the first embodiment.
The server 1 is connected to the client 2 via the network 3, and the server 1 connects to the RDB 15 and includes a stored procedure 17 and a stored procedure starting unit 14.
The client 2 is provided with the application 16 and the RDB 1 of the first embodiment.
1, RDBMS 12, stored procedure 13, and application 21 are replaced with RDB 15, RDBMS 16, stored procedure 17, and application 22.

Here, RD different from that of the first embodiment is used.
The B15, the RDBMS 16, the stored procedure 17, and the application 22 will be described.

The RDB 15 is a relational database for storing and accumulating data, and includes a base table A 151, a base table B 152, and a base table C.
153. The base table A151 is the basic data, and the base table B152 and the base table C153 hold the history of the base data.

The real table A 151 is one of the tables constituting the RDB 15. FIG. 7A shows the configuration of the base table A151. Base table A151 includes a product number and a product name,
Each row is uniquely identified by the product number which is the primary key.

The real table B 152 is one of the tables constituting the RDB 15. FIG. 7B shows the configuration of the base table B152. The base table 152 includes a product number, a branch number A, a reception number, and a deletion. The product number corresponds to the product number of the base table A151, and thereby the base table 152 and the base table A151 are related. The branch number A indicates the order of the reception number within the same product number, and may be a serial number or a date and time.
Each line is uniquely identified by “product number + branch number A”. The reception number is a serial number assigned throughout the product, and the reception number is registered each time a failure of the product is received. The content of the failure is registered in the base table C153. If there is a new fault reception for the same product, the branch number A is increased and a new reception number is registered. The deletion indicates whether or not the reception number has been once received and then deleted. When the reception number has been deleted, “DEL” is indicated.

The real table C 153 is one of the tables constituting the RDB 15. FIG. 7C shows the configuration of the base table C153. The base table C153 includes a product number, a branch number A, a branch number B, and a failure content. "Product number + branch number A" is base table B152
"Product number + branch number A", thereby associating the base table C153 with the base table B152. The branch number B indicates the order of the failure contents within the same “product number + branch number A”, and may be a serial number or a date and time. "Product number +
Each row is uniquely distinguished by “branch number A + branch number B”. In the trouble content, the trouble content corresponding to the reception number is registered. When the failure content for the received receipt number is updated, the updated failure content is registered by increasing the branch number B, and history management is performed as separate data.

The RDBMS 16 manages and accesses the RDB 15. A request issued from the application 22 is processed, and a processing result corresponding to the issued request is returned to the application 22.

The stored procedure 17 has a base table A15
1, a virtual table A17 based on the real table B152 and the real table C153.
1 is defined and a data set is selected and created. The stored procedure 17 is activated by the stored procedure activation means 14. The name of the virtual table A 171 is determined when the stored procedure 17 is registered in the RDBMS 16. By specifying this name, the application 22 can refer to the virtual table A 171 generated by the stored procedure 17. In addition,
A method for registering the stored procedure 17 in the RDBMS 16 is based on a known method.

The virtual table A 171 is a virtual table including the latest history unique key. The stored procedure 17 generates a definition based on the base table A151, the base table B152, and the base table C153, and generates the largest branch number A and the same base table C153 in the product number of the base table A151 and the same product number of the base table B152. The selection condition for combining with the largest branch number B in “product number + branch number A” is specified. FIG. 7C shows the configuration of the virtual table A171. The virtual table A171 includes a product number, a branch number A, and a branch number B. The product number corresponds to the product number of the base table A151, the branch number A corresponds to the largest branch number A in the same product number of the base table B152, and the branch number. The number B corresponds to the largest branch number B in the same “product number + branch number A” of the base table C153. The virtual table A 171 always serves as an index reflecting the latest state of the RDB 15 from the viewpoint of the application 22, and is referred to by the application 22.

The application 22 executes the stored procedure 17 to obtain the latest data of the RDB 15.
Defines a virtual table B 221 associated with the virtual table A 171 defined and generated, and issues an access request to the RDBMS 16. The processing result corresponding to the issued request is RDBM
Data processing is performed based on the data returned from S16 and acquired.

The virtual table B 221 is a virtual table defined and generated by the application 22 based on the virtual table A 171, the real table A 151, the real table B 152 and the real table C 153, and includes data required by the application 22. Virtual table B22
7 is shown in FIG. 7 (d). The virtual table B 221 includes a product number, a product name, a reception number, and a failure content, and the product number is a real table A 151 corresponding to the product number of the virtual table A 171.
, The product name is the product name of the base table A151 corresponding to the product number of the virtual table A171, and the reception number is the base table B15 corresponding to “product number + branch number A” of the virtual table A171.
2, and the failure content corresponds to the failure content of the real table C153 corresponding to "product number + branch number A + branch number B" of the virtual table A171.

The operation of the second embodiment of the present invention will be described in detail with reference to FIGS.

FIGS. 8A and 8B are diagrams for explaining the operation of the second embodiment. FIG. 8A shows a specific example of the base table A151, FIG. 8B shows a specific example of the base table B152, and FIG. C153 shows a specific example, (d) shows a specific example of the virtual table A171, and (e) shows a specific example of the virtual table B221. In (b), the reception numbers “002” and “003” were once received but were subsequently deleted, so “DE” was deleted.
L ". FIG. 9 is a diagram showing the flow of the operation of the second embodiment.

Referring to FIG. 9, the application 22
Associates the product number of the real table A151 with the product number of the virtual table A171, and “product number + branch number A” of the real table B152.
And the “product number + branch number A” of the virtual table A171, and the “product number + branch number A + branch number B” of the real table C153 and the “product number + branch number A + branch number B” of the virtual table A171. Are defined, a virtual table B221 including a product number, a product name, a reception number, and a failure content is defined, and an access to the RDB 15 is requested to the RDBMS 16 (steps A21 to A21).
A22).

The RDBMS 16 is used by the application 22
Is analyzed (step M21), and when the virtual table A 171 defined and generated by the stored procedure 17 is specified, it is determined whether or not the stored procedure 17 needs to be started and executed. When it is recognized that the procedure 17 needs to be activated, the stored procedure 17 is activated (steps M22 to M24). If the specified stored procedure 17 has already been started and executed and the RDB 15 has not been updated thereafter, the stored procedure 17 is not started. In this case, the processing result of the stored procedure 17 already executed is used.

The started stored procedure 17 executes the following processing. (1) For each “product number + branch number A” in the base table C153, a row including the largest branch number B in the same “product number + branch number A” is selected (step S21). In this example, FIG.
The line with a circle at the right end of (c) is selected. (2) The “product number + branch number A” of the base table 152 is associated with the “product number + branch number A” of the result (1) (step S22). At this time, “product number + branch number A” of the base table B152 in which “DEL” is set to delete the base table B152 is excluded. In this example, the reception number “002”
The lines “003” and “003” are excluded because “DEL” is set for deletion, and are related to the lines marked with “◎” at the right end in FIGS. 8B and 8C. (3) A virtual table A1 including the product number of the real table A151, the branch number A of the result of the above (2), and the branch number B of the result of the above (2).
A 71 data set is created (step S23). FIG. 8D shows the output result of the stored procedure 17.

Subsequently, the RDBMS 16 stores the virtual table B 221
(Step M25). RDBMS1
The processing result of No. 6 is shown in FIG.

Thereafter, the RDBMS 16 returns a processing result to the application 22 (Step M26).

The application 22 executes the RDBMS 16
And performs application processing (step A23).

In this way, the application 22
By using the virtual table A171, which is the output result of the stored procedure 17, instead of an index,
The latest data of the required RDB 15 can be obtained at high speed. That is, the application 22 can perform the processing by acquiring the latest reception number and the failure content for the product number without performing complicated processing.

In the above-described embodiment of the present invention, a program for executing a processing operation of the database access method is stored as data in a storage device (not shown) such as a magnetic disk or an optical disk.
It is used to read out the stored data and operate the database access method. As described above, the data for operating the database access method according to the present invention is stored in the storage medium, and the function of the database access method can be realized by installing the storage medium.

[0075]

The first effect is that the latest data can always be referred to at a high speed from the application simply by referring to the necessary stored procedure. The reason is that a means is provided for configuring the function of generating an index for an application in a stored procedure.

The second effect is that the load on the client is reduced and the traffic on the network is also reduced. The reason is that the stored procedure is executed on the server side, so complicated SQL
Need not be issued, the application can construct the process simply by describing the data operation process based on the unique key table.
This is because the number of exchanges with the DBMS can be reduced.

The third effect is that when a database failure occurs, no special recovery processing such as re-creation of a physical index table for an application index is required. The reason is that the application index uses stored procedures as virtual tables.

[Brief description of the drawings]

FIG. 1 illustrates the present invention.

FIG. 2 is a diagram showing a configuration of a first embodiment.

FIG. 3A shows a base table A (b) according to the first embodiment;
Diagram showing the structure of the real table B (c), the virtual table A (d) and the virtual table B

FIG. 4 is a diagram illustrating an operation of the first embodiment (a) a real table A (b) a real table B (c) a virtual table A (d) a virtual table B

FIG. 5 is a diagram showing a flow of an operation according to the first embodiment;

FIG. 6 is a diagram illustrating a configuration according to a second embodiment;

FIG. 7A shows a base table A (b) according to the second embodiment;
Diagram showing configuration of base table B (c) base table C (d) virtual table A (e) virtual table B

FIG. 8 is a view for explaining the operation of the second embodiment (a) a base table A (b) a base table B (c) a base table C (d) a virtual table A (e) a virtual table B

FIG. 9 is a diagram showing a flow of an operation according to the second embodiment;

FIG. 10 is a diagram illustrating a result of (a) a base table A (b) and a base table B (c) illustrating a conventional operation;

[Explanation of symbols]

 Reference Signs List 1 server 2 client 3 network 4 database 5 database management system 6 stored procedure execution means 7 database access request means 11 RDB 12 RDBMS 13 stored procedure 14 stored procedure activation means 15 RDB 16 RDBMS 17 stored procedure 21 application 22 application 111 base table A 112 Base table 131 Virtual table A 151 Base table A 152 Base table B 153 Base table C 171 Virtual table A 211 Virtual table B 221 Virtual table B

Claims (7)

[Claims] A database for storing and storing data;
A database management system that receives a request from a database access requesting unit, accesses the database and returns an access result to the database access requesting unit, executes a stored procedure included in the database management system, and stores a unique key defined in the stored procedure. Stored procedure execution means for creating a table, and database access request means for requesting the database management system to access the database with reference to the unique key table created by the stored procedure execution means. Database access method. 2. In a client-server system in which a server and a client are connected via a network, the server stores and accumulates data based on a relational database composed of one or more base tables and a process requested by an application. A relational database management system that accesses the relational database and returns a processing result to the application, a stored procedure that defines a virtual table associated with the base table and creates a unique key table,
And a stored procedure starting means for starting the stored procedure, wherein the client issues a request for accessing the relational database by specifying a virtual table defined by the stored procedure to the relational database management system, and A database access method comprising an application received from a relational database management system. 3. The stored procedure starting means,
3. The database access method according to claim 2, wherein the stored procedure is not started if the stored procedure has already been started and executed and the relational database has not been updated thereafter. 4. The database access method according to claim 2, wherein the virtual table defined by the stored procedure serves as an index when an application accesses the relational database. 5. A method for accessing a database in a client server system in which a server and a client are connected via a network, wherein an application associates a base table with a virtual table defined by a stored procedure. And making an access request to the relational database to the relational database management system.The relational database management system analyzes the access request from the application, and stores a virtual table defined by the stored procedure when the virtual table defined and generated is specified. Invoking and executing a procedure to generate a virtual table defined in a stored procedure, process an access request of an application using the virtual table, and return a processing result to the application; A database access method characterized by receiving a processing result from a physical system. 6. The stored procedure according to claim 1, wherein the stored procedure is a process for generating a virtual table including a latest history unique key from a base table of basic data and two or more base tables holding its history. Item 6. The database access method according to Item 5. 7. An access request process in which an application defines a table associating a base table with a virtual table defined by a stored procedure and issues an access request to a relational database to a relational database management system, and said relational database management. The system analyzes an access request from the application, and executes a stored procedure start process for starting the stored procedure when a virtual table defined and generated by the stored procedure is specified. A virtual table generating process for generating a defined virtual table; an access process for processing an access request of an application using the virtual table and returning a processing result to the application; A recording medium on which a program for causing a computer to execute a data receiving process of receiving a processing result from a computer is recorded.