JPH04343150A - Data base system - Google Patents

Abstract

PURPOSE:To simplify a virtual table definition by selecting directly the line of a basic table to exist at other site and defining the virtual table. CONSTITUTION:A virtual table defining means 1 performs the line information obtaining request of a basic table to a data base access means 3. A dispersion data base access means 4 informed of a remote line information obtaining request from the data base access means 3 refers to a location control dictionary 7, determines the site where the designated basic table exists, and performs the line information obtaining request through communication means 8 and 11 and a dispersion data access means 10 to a data base access means 9 on the site. The data base access means 9 refers to a directory file 12, obtains the designated definition information and returns the line information through the dispersion data base access means, the communication means 11 and 8 and a dispersion data base access means 4 to the data base access means 3. The virtual table defining means 1 stores a virtual table definition information record 51 onto a designated directory file 5.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention is utilized for controlling a database. The present invention relates to a database system that controls virtual tables (hereinafter referred to as virtual tables) that are defined based on basic tables and do not store actual data records.

0002

2. Description of the Related Art In conventional database systems, virtual tables are used as a mapping function to convert source data (hereinafter referred to as basic tables) into presentation formats required by various application programs. By using this virtual table, the user can redefine fields and use multiple base tables as one table without making any changes to the base table.

0003

[Problems to be Solved by the Invention] In the conventional method described above, a virtual table can only be defined in a directory where the underlying basic table exists, and a virtual table can only be defined in a directory where the underlying basic table exists. It was not possible to select the column directly. Therefore, if you are trying to define a virtual table that selects columns from a base table that exists at another site, you must copy the base table to the site where you want to define the virtual table, select the columns of the copied base table, and then This was done indirectly by defining a table. In this case, it is difficult to maintain the consistency of table definition information and stored data between the site where the original base table exists and the copied base table.

[0004] The present invention solves this problem, and when defining a virtual table, if the original basic table exists in another site, the location information of the site where the basic table exists is added to the location management dictionary. By making it possible to define a virtual table by directly selecting the columns of a base table that exists on another site, it is possible to simplify virtual table definition, and to save table definition information and table definition information during virtual table operation. The purpose is to provide a system that can maintain the consistency of stored data.

[0005]

[Means for Solving the Problems] The present invention has a plurality of computers connected to each other, and each of the plurality of computers stores a communication means for communicating and a location management record in which location information of a table is recorded. In a database system that includes a location management dictionary, a directory file that stores virtual table definition information records in which virtual table definition information is recorded, and a database file that stores data, a database user can store virtual tables on each of the computers. When a definition request is made, a column information acquisition request is made for the specified virtual table definition information to obtain column information of the base table that makes up the virtual table for each column that makes up the virtual table. The validity of the table definition request is confirmed, and if it is correct, a virtual table definition storage request is made to store the virtual table definition information in the specified directory file, and if the user's virtual table definition request is incorrect, is a virtual table definition means that notifies a user of an error, and when a column information acquisition request is notified from this virtual table definition means, refers to the directory file specified in the virtual table definition and constructs a virtual table. When the basic table and columns exist, return column information to the virtual table definition means; when they do not exist, make a remote column information acquisition request, and return the returned column information or an error to the virtual table definition means; Further, when the virtual table definition information storage request is notified from the virtual table definition means, the database access means stores the virtual table definition in the directory file specified by the user, and the database access means stores the remote column information. When an acquisition request is notified, the location management dictionary is accessed to determine the location of the specified basic table, a column information acquisition request is made to the database access means on the determined site via the communication means, and the specified The present invention is characterized by comprising a distributed database access means for returning column definition information to the database access means on the client side when the basic table and column are present.

[0006] The database access means is configured to detect, when a virtual table is accessed by a user program using the database file, that a basic table constituting the virtual table exists in a directory file on a site where the user program is executed. accesses the data in the corresponding basic table, converts it to the specified virtual table format, and returns it to the user program; if it does not exist in the directory file on the site where the user program was executed, the specified The distributed database access means includes means for making a remote column data acquisition request in order to acquire column data of the specified basic table, converting the returned data into a specified virtual table format, and then returning it to the user program, When a remote column data acquisition request is notified from the database access means, the location management dictionary is accessed to determine the location of the designated basic table, and the data is sent to the database access means on the determined site via the communication means. It is desirable to include means for making a column data acquisition request for a specified basic table and returning the acquired data to the database access means on the client site.

[0007]

[Operation] When a virtual table definition request is made by a database user, the virtual table definition means generates column information of the original basic table for each column composing the virtual table regarding the specified virtual table definition information. In order to obtain this information, a column information acquisition request is made and the validity of the user's virtual table definition request is confirmed. If it is correct, a virtual table definition information storage request is made to store the virtual table definition information on the specified directory file, and if the user's virtual table definition request is incorrect, the user is notified of an error.

[0008] When the database access means is notified of a column information acquisition request from the virtual table definition means, the database access means refers to the directory file specified in the virtual table definition, and retrieves the column information when the original basic table and columns exist. If the column information does not exist, a remote column information acquisition request is made, and the returned column information or error is returned to the virtual table definition means. Further, when a virtual table definition information storage request is notified from the virtual table definition means, the virtual table definition is stored in the directory file specified by the user.

[0009] When the distributed database access means is notified of a remote column information acquisition request by the database access means, the distributed database access means accesses the location management dictionary, determines the location of the designated basic table, and accesses the database on the determined site. A request to obtain column information is made via the communication means. If the specified base table and column exist, that information is returned to the database access means on the client side.

[0010] Furthermore, when a virtual table is accessed by a user program that uses a database,
When the basic tables that make up the virtual table exist in the directory file on the site where the user program is executed, the database access means accesses the data of the corresponding basic table, converts it into the specified virtual table format, and then converts the data into the specified virtual table format. , and return it to the user program. If the user program does not exist in the directory file on the site where it is executed, a remote column data acquisition request is made to acquire the column data of the specified basic table, and the returned data is converted into the format of the specified virtual table. It is then returned to the user program.

[0011] When the distributed database access means is notified of a remote column data acquisition request by the database access means, the distributed database access means accesses the location management dictionary, determines the location of the designated basic table, and accesses the database on the determined site. A request is made to obtain the column data of the specified basic table via the communication means, and the obtained data is returned to the database access means on the client site.

[0012] This makes it possible to define a virtual table that directly selects the columns of a basic table existing at another site, and compared to indirect virtual tables created using the conventional method, table definition The consistency of information and stored data can be maintained.

[0013]

Embodiments Next, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a diagram showing the configuration and processing flow of an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a virtual table definition information record according to an embodiment of the present invention, and FIG. 3 is a diagram showing a location management record according to an embodiment of the present invention. FIG. 3 is a diagram showing the configuration.

In the embodiment of the present invention, a plurality of computers are connected to each other, and each of the plurality of computers has a communication means 8 for communicating and a location management record 71 in which location information in a table is recorded. The present invention is equipped with a dictionary 7, a directory file 5 for storing virtual table definition information records 51 in which virtual table definition information is recorded, and a database file 6 for storing data. When a user makes a virtual table definition request, a column information acquisition request is made for the specified virtual table definition information to obtain column information of the base table that makes up the virtual table for each column that makes up the virtual table. , confirms the validity of the user's virtual table definition request, and if it is correct, issues a virtual table definition storage request to store the virtual table definition information in the specified directory file 5, and accepts the user's virtual table definition request. virtual table definition means 1 that notifies the user of an error if the virtual table definition means 1 is incorrect, and refers to the directory file 5 specified in the virtual table definition when a column information acquisition request is notified from this virtual table definition means 1. However, when the basic table and columns constituting the virtual table exist, column information is returned to the virtual table definition means 1, and when they do not exist, a remote column information acquisition request is made,
The returned column information or error is returned to the virtual table definition means 1, and when the virtual table definition information storage request is notified from the virtual table definition means 1, the virtual table definition information is stored in the directory file 5 specified by the user. A database access means 3 that stores table definitions; when a remote column information acquisition request is notified from the database access means 3, the location management dictionary 7 is accessed to determine the location of the specified basic table;
A distributed database that makes a column information acquisition request to the database access means 9 on the determined site via the communication means, and returns column definition information to the database access means 3 on the client side if the specified basic table and column exist. database access means 3;
In this case, when the user program 2 that uses the database file 6 accesses the virtual table,
If the basic table constituting the virtual table exists in the directory file 5 on the site where the user program 2 is executed, the user program accesses the data of the corresponding basic table and converts it into the specified virtual table format. 2, and if it does not exist in the directory file 6 on the site where the user program 2 is executed, a remote column data acquisition request is made to acquire the column data of the specified basic table, and the returned data is specified. When the distributed database access means 4 is notified of a remote column data acquisition request by the database access means 3,
The location management dictionary 7 is accessed to determine the location of the specified basic table, and a request is made to the database access means 9 on the determined site via the communication means 8 and 9 to obtain the column data of the specified basic table. It includes means for returning the obtained data to the database access means 3 on the client site.

Next, the operation of the embodiment of the present invention constructed as described above will be explained. First, a case will be described in which a virtual table is defined by selecting columns of a table that exists at another site.

When a database user makes a virtual table definition request to the virtual table definition means 1, the virtual table definition means 1 inspects the virtual table definition request specified by the user, and identifies each column constituting the virtual table. In order to obtain column information of the basic tables that constitute the virtual table, a column information acquisition request is made to the database access means 3. The database access means 3, which has been notified of the column information acquisition request, refers to the directory file 5, and if information regarding the specified basic table and column exists, acquires the corresponding definition information, and the virtual table definition means 1
Return it to. If the specified basic table does not exist, the database access means 3 requests the distributed database access means 4 to obtain remote column information.

The distributed database access means 4 that has been notified of the remote column information acquisition request refers to the location management dictionary 7 and records the location management record 71 that describes the location of the specified table.
Search for. If the location management record 71 describing the location of the specified table does not exist, an error is returned to the database access means 3. The location management record 71 that describes the location of the specified table is stored in the location management dictionary 7.
If the specified basic table exists, the location information is obtained, the site where the specified basic table exists is determined, and the communication means 8 and the communication means 1 are sent to the database access means 9 on the corresponding site.
1. Make a column information acquisition request via the distributed database access means 10.

The database access means 9 that has been notified of the column information acquisition request refers to the directory file 12,
The specified definition information is acquired and returned to the distributed database access means 10. The distributed database access means 10 to which the table definition information has been returned returns the column information to the database access means 3 via the communication means 11, the communication means 8, and the distributed database access means 4.

[0019] When the definition information of all the columns constituting the virtual table specified by the user can be obtained, the virtual table definition means 1
is a virtual table attribute field 511 indicating field attributes on the virtual table shown in FIG. 2 on the specified directory file 5, a base table column name field 513 indicating the column name on the base table corresponding to the column of the virtual table, A virtual table definition information record 51 having a basic table name field 512 indicating the basic table name is stored. If an error is returned in the column information acquisition request, the virtual table definition means 1 returns an error to the user to indicate that there is an error in the virtual table definition information specified by the user.

Next, the case where the user program 2 accesses the virtual table will be explained.

When the user program 2 notifies the database access means 3 of access to a virtual table, the database access means 3 accesses the directory file 5 and obtains the specified virtual table definition information record 51. The database access means 3 refers to the basic table name field 512 and the basic table column name field 513 of the acquired virtual table definition information record 51, and acquires the attributes of the basic table from the directory file 5 for each column that constitutes the virtual table. , obtain column data from the database file 6.

Basic table name field 512 of virtual table definition information record 51 acquired by database access means 3
If the basic table described in the table does not exist in the directory file 5, the database access means 3 specifies the table name described in the basic table name field 512 and the column name described in the basic table column name field 513. Then, a remote column data reference request is made to the distributed database access means 4.

The distributed database access means 4, which has been notified of the remote column data reference request, refers to the location management record 71 in the location management dictionary 7, determines the site where the designated basic table exists, and communicates with the communication means 8. The means 11 makes a column data acquisition request to the database access means 9 of the corresponding site via the distributed database access means 10.

The database access means 9, which has been notified of the column data acquisition request, retrieves from the directory file 12,
At the same time as acquiring the attributes of the basic table, column data is acquired from the database file 13 and returned to the distributed database access means 10.

The distributed database access means 10 that received the attributes and column data of the basic table returns them to the database access means 3 via the communication means 11, the communication means 8, and the distributed database access means 4.

After acquiring the attributes and column data of all the columns constituting the virtual table, the database access means 3 converts the column data into the attributes specified in the virtual table attribute field and returns it to the user program 2 as a record. .

[0027]

[Effects of the Invention] As explained above, according to the present invention, even if the original basic table constituting a virtual table exists in another site, the location information of the site where the basic table exists is defined in the location management dictionary. By doing so, it is possible to define a virtual table that directly selects the columns of a base table that exists on another site, which simplifies the virtual table definition, and also makes it possible to save table definition information and storage when operating the virtual table. This has the effect of maintaining the consistency of data.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration and processing flow of an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a virtual table definition information record according to the embodiment of the present invention.

FIG. 3 is a diagram showing the structure of a location management record according to the embodiment of the present invention.

[Explanation of symbols]

1 Virtual table definition means 2 User programs 3, 9 Database access means 4, 10 Distributed database access means 5, 12
Directory files 6, 13 Database file 7 Location management dictionary 8, 11 Communication means 51 Virtual table definition information record 71 Location management record 511 Virtual table attribute field 512 Basic table name field 513 Basic table column name field 711 Table name field 712 Location information field

Claims (2)

[Claims] Claim 1: A plurality of computers are connected to each other, and each of the plurality of computers has a communication means for communicating, a location management dictionary that stores a location management record in which location information of a table is recorded, and a virtual table definition. In a database system that includes a directory file that stores virtual table definition information records in which information is recorded and a database file that stores data, when a database user makes a virtual table definition request to each of the computers, Regarding the specified virtual table definition information, perform a column information acquisition request to obtain column information of the basic table that makes up the virtual table for each column that makes up the virtual table, and check the validity of the user's virtual table definition request. Then, if it is correct, a virtual table definition storage request is made to store the virtual table definition information on the specified directory file, and if the user's virtual table definition request is incorrect, the user is notified of an error. A virtual table definition means, and when a column information acquisition request is notified from this virtual table definition means, the directory file specified in the virtual table definition is referred to, and basic tables and columns forming the virtual table exist. Sometimes, the column information is returned to the virtual table definition means, and when the column information does not exist, a remote column information acquisition request is made, and the returned column information or an error is returned to the virtual table definition means. When a virtual table definition information storage request is notified, a database access means stores a virtual table definition in the directory file specified by the user, and when a remote column information acquisition request is notified from this database access means. , determines the location of the specified basic table by accessing the location management dictionary, sends a column information acquisition request to the database access means on the determined site via the communication means, and determines that the specified basic table and column exist. a distributed database access means for returning column definition information to the database access means on the client side when the database access means is used. 2. The database access means, when a user program that uses the database file accesses the virtual table, the basic table constituting the virtual table is a directory file on the site where the user program is executed. accesses the corresponding basic table data, converts it to the specified virtual table format, and returns it to the user program; if it does not exist in the directory file on the site where the user program was executed, The distributed database access means includes means for making a remote column data acquisition request in order to acquire column data of a designated basic table, converting the returned data into a format of a designated virtual table, and then returning it to the user program. When the remote column data acquisition request is notified from the database access means, the communication means accesses the location management dictionary to determine the location of the designated basic table, and sends the database access means on the determined site to the communication means. 2. The database system according to claim 1, further comprising means for making a column data acquisition request for a designated basic table via a client site and returning the acquired data to the database access means on the client site.