JPH1055302A - Expression method for inter-class inheritance relation on database - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of both message communication frequency and access frequency to a database by having an access to the database of attribute data of the class that is designated via an attribute management table prepared for each of attribute data existing in every class. SOLUTION: A class data management part 121 of a database control part 12 contains an attribute management table to decide whether the inheritance relation are confirmed among the class attributes and then to decide the inheritance origin and the short instance, etc., if the inheritance relation is confirmed. An attribute decision processing part 122 decides a specific class attribute where the attribute inheritance origin belongs via the attribute management table of the part 121 and by means of an attribute identifier of the parameter that is edited at an application part 11. At the same time, an instance editing part 123 converts an object instance of the inputted parameter into the instance of the inheritance origin class via the attribute management table of the part 121.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for expressing attribute data on a database in which the same attribute data exists in a plurality of classes.

[0002]

2. Description of the Related Art In a conventional information processing apparatus, attribute data (for example, numeric data, alphabetic data,
Kanji data) exists in multiple classes. Here, the above-mentioned “class” means a class that classifies data items according to the contents that the data items can include. For example, there are hierarchical classes such as an upper class, a middle class, and a lower class. In each of the plurality of classes, some attribute data existing in the own class is independently managed by each instance.

[0003] Here, the above "instance" refers to an "entity" (object) generated from a class and belonging to the class, and is also called an "instance object". Since a class is also an instance (entity) generated by some kind of “concept or definition”, it can be said that an object is another name for an instance. According to the concept described above, "object-oriented" is used to (1) implement functions by modularizing functions and transmitting messages; (2)
It is expected that the code is centralized by separating the class (definition) and the instance (substance), and that (3) the code amount is saved by inheriting the function (inheriting from the upper class to the lower class).
For this reason, changing attribute data in the related art requires transmitting a message to each class that manages the attribute data.

[0004]

However, in the method of the prior art, in order to change the attribute data, a message is transmitted to each class that manages the attribute data. And the processing takes a long time.

[0005]

According to the present invention, there is provided a method for expressing an inheritance relationship between classes on a database, wherein the attribute data is expressed on a database in which the same attribute data exists in a plurality of classes. An attribute management table including the presence or absence of an inheritance relationship, an inheritance source class and a missing instance is provided for each attribute data existing in each class, and the attribute data of the class specified using the attribute management table is stored in the database. Access. By centrally managing the inheritance relationship between the classes of the attribute data on the database, the memory can be reduced by reducing the database, and the management information between the distributed classes can be matched. Also, the number of message communications and the number of accesses to the database are reduced.

[0006]

FIG. 1 is a diagram showing a configuration example of an attribute management table according to the present invention. The attribute management table shown in FIG. 1 stores, for each attribute data existing in a plurality of classes (for example, in class A, attribute data a, b, c, d, and class B
, The attribute data a, e, and f, and the attribute data a, g, and h in the class C). The presence / absence of the inheritance relationship, inheritance source class, and missing instance will be described with reference to FIG.

FIG. 2 is a diagram for explaining the inheritance of the attribute data of each class in FIG. FIG. 2 explains how the attribute data of each class in FIG. 1 is inherited. First, the attribute data a of the class A also exists as the attribute data of the classes B and C. In this example, the class A is the upper class, the class B is the middle class, and the class C is the lower class. In this case, the lowest class C is the inheritance class of the attribute data a, and is managed on the database as the class C attribute data. When the attribute data a of the class A is specified and the database is accessed, it is necessary to convert the attribute data a into the attribute data a of the class C which is the inheritance source. There is a C instance.

The attribute data b of the class A is the class D
Also exists as attribute data of class A, and attribute data c of class A
Also exists as class E attribute data. Since class D and class E are both lower classes than class A, the class from which attribute data b is inherited is class D and the class from which attribute data c is inherited is class E. It is managed as class attribute data. Similarly, attribute data b of class A is specified,
When accessing a database, it is necessary to convert the attribute data into the attribute data of the class D that is the inheritance source, and a class D instance is an instance lacking in this conversion.

FIG. 3 is a system configuration diagram for realizing access to a database according to the present invention. The system shown in FIG. 3 includes an application unit 11 that edits information of a plurality of classes, a database control unit 12 that controls keys for searching a database, and a data management unit 13 that manages data. Application part 1
Reference numeral 1 denotes a class 111 (an class A to a class E in this example) having an inheritance relationship and a target class and a target instance which are necessary when changing or reading the attribute of the class 111.
The parameter editing unit 112 edits class information such as an attribute identifier.

The database control unit 12 incorporates the attribute management table shown in FIG. 1 and determines whether or not the attributes of each class are in an inheritance relationship. The class data management unit 121 which is managed by the table and the attribute identifier of the parameter edited by the application unit 11 determines which class attribute the inheritance source of the attribute is in the class data management unit 121 in the attribute management of FIG. An attribute determination processing unit 122 that determines from a table, an instance editing unit 1 that converts an instance from the attribute management table of FIG. 1 in the class data management unit 121 into an instance of an inheritance class from a target instance of an input parameter
23 and a database access processing unit 124 that obtains a relation name, the number of key stages, a key value, and the like necessary for database access from the result of the instance editing unit 123.
It is composed of The data management unit 13 includes a database editing unit 131 that accesses the database 132 from the key edited by the database control unit 12 and a database 132 in which attributes of each class are managed by a relation name, the number of key stages, a key value, and the like. You. In the database 132 of the present invention, the attribute data expressing the same meaning in the classes having the inheritance relation is centrally managed.

FIG. 4 is a flow chart showing the sequence of operations for accessing the database of the attribute data of the designated class according to the present invention, and the numeral following S in the figure indicates a step number. To access a database of attribute data of a certain class, first, the application unit 11 in FIG.
The necessary target class, target instance, attribute identifier, and the like are set (see S1 in FIG. 4). Then, the input target instance is extracted by the database control unit 12 in FIG. 3 (see S2 in FIG. 4). Next, the attribute of the input target class is extracted, and the process branches to the corresponding class according to the extracted attribute (see S3 in FIG. 1). In each of the branched classes, it is determined whether or not the input attribute data has the inheritance relationship by referring to the presence / absence of the inheritance relationship in the attribute management table of each class in FIG. 1 (see S4 in FIG. 4). ). Then, different processes are performed depending on the result of the determination as to whether or not the input attribute data has an inheritance relationship.

When the input attribute data has an inheritance relationship,
First, the class set as the inheritance class in FIG. 1 is set (see S5 in FIG. 4). Next, the extracted target instance is converted into an instance of an inheritance source class using the instance set as the missing instance in FIG. 1 (see S6 in FIG. 4). Next, a key (relation name, number of key stages, key value, etc.) necessary for accessing the database is set from the converted instance (see S8 in FIG. 4). The setting of this inherited class,
By performing the instance conversion to the class of the inheritance source, it is possible to access the database of the attribute of the inheritance source. Then, using the key set in S8, access to the database of the attribute data of the input class is executed (see S9 in FIG. 4). If the input attribute data does not have an inheritance relationship, the extracted target instance is set as the instance as it is (see S7 in FIG. 4). Then, a key (relation name, number of key steps, key value, etc.) necessary for accessing the database is set (S in FIG. 4).
8). Then, using the key set in S8, access to the database of the attribute data of the input class is executed (see S9 in FIG. 4). Thus, the access to the database of the attribute data of the specified class is completed.

In the above embodiment, an example has been described in which attribute data of classes in an inheritance relationship is managed on a database by obtaining necessary keys (relation names, number of key stages, key values, etc.) from instances of each class. If the attribute data of the classes having the inheritance relationship is managed for each class, it can be managed on the database using the data as a key.

As described above, in the present invention, the inheritance relationship between the classes of the attribute data is centrally managed on the database, so that the memory can be reduced by reducing the database, and the mutual management information between the classes can be reduced. Is matched. Also, the number of message communications and the number of accesses to the database are reduced.

[0015]

As described above, according to the present invention, in a method for expressing attribute data on a database in which the same attribute data exists in a plurality of classes, in each of the attribute data existing in the plurality of classes, An attribute management table including the presence / absence of an inheritance relationship, an inheritance source class, and a missing instance is provided. The attribute management table is used to access the database of the attribute data of the designated class. The inheritance relationship between classes can be centrally managed on the database, the memory can be reduced by reducing the database, the management information between the distributed classes can be coordinated, the number of message communications and the access to the database The effect of reducing the number of times is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an attribute management table according to the present invention.

FIG. 2 is a diagram illustrating inheritance of each class in FIG. 1;

FIG. 3 is a system configuration diagram for realizing access to a database according to the present invention.

FIG. 4 is a flowchart showing the sequence of operations for accessing a database according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Application part 12 Database control part 13 Data management part 111 Class 112 Parameter editing part 121 Class data management part 122 Attribute judgment processing part 123 Instance editing part 124 Database access processing part 131 Database editing part 132 Database

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Makoto Kurosawa 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Claims] 1. A method for expressing attribute data on a database in which the same attribute data exists in a plurality of classes, wherein each attribute data in each of the plurality of classes has an inheritance relationship, an inheritance source class, A method for expressing an inheritance relationship between classes on a database, comprising: providing an attribute management table including a missing instance; and accessing the database of attribute data of a specified class using the attribute management table. 2. A method for accessing the database of attribute data of the specified class is as follows. First, at least a target class, a target instance, and an attribute identifier are set for the attribute data of the specified class. Then, the target instance of the attribute data of the specified class is extracted.Next, by referring to the attribute management table, it is checked whether or not the attribute data of the specified class has an inheritance relationship. Is set to the class set in the inherited class first, then converted to an instance of the inherited class using the instance set to the missing instance, and if there is no inheritance relationship, the extracted Set the instance as it is, and then convert the database from the converted or set instance. 2. A database for inheritance relationships between classes according to claim 1, wherein a key required for access is set, and then the database of attribute data of the specified class is accessed using the set key. Expression method above.