JPH05266076A - Data base definition generator with data restriction information and data restriction information adding device - Google Patents

Abstract

PURPOSE:To apply data restriction information to data base definition without the danger of generating programming error. CONSTITUTION:This device is provided with a substance relative restriction information input means 1 to input substance information in substance relative models, the relative information of those substances and restriction information concerning substances or the relation corresponding to a method when the substances are made to correspond to classes in object directivity, storing means 2 to store the substance information, relative information and restriction information inputted by the substance relative restriction information input means 1, and data base definition generating means 3 to generate the data base definition in which data restriction information is incorporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database definition generation device for a database (database schema, database frame) that needs to store a large amount of data consistently.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a database.
It constitutes a database of employees of a company. This database is completed by inputting various data into its database definition (for example, SQL language is known as a language for describing it). That is, for example, code data of 123 is input to the employee code column, name data of Nakamura is input to the name column, and age data of 20 is input to the age column. In this way, the employee code, name, and age data relating to various people are input and the database is completed.

Then, as a matter of course, when the data is entered into the database definition of such an employee and completed, the employee code is, for example, greater than 1 and 500.
There is a data restriction that it is smaller, and the name is *,%
There are various restrictions such that special symbols such as "" cannot be input, and that the number cannot be 1, 2, or 200. Therefore, when accepting and inputting data to the database definition, the validity of the input data must be checked.

[0004]

By the way, the constraint that must be satisfied in order to maintain the consistency between the data stored in such a database is conventionally described and managed by the programmer himself during the programming for accessing the database. ing.

However, there are many programs that access such a database.

In each of such programs,
There is a problem in that it is necessary to describe the same constraint in order to maintain consistency, so that there is a high possibility that a redundancy programming error will occur.

The present invention has been made in consideration of such problems of the conventional database technology, and an object of the present invention is to provide a database definition generating device with data constraint information and a data constraint information adding device which are free from the risk of programming errors. Is.

[0008]

According to the present invention, the entity information in the entity relation model, the relation information of the entities, and the entity or the association corresponding to the method when the entity is associated with a class in object orientation. Entity-related constraint information input means capable of respectively inputting constraint information regarding the entity, storage means for storing the entity information, related information and constraint information input by the entity-related constraint information input means, and the entity information and related information. And a database definition generating means for converting the constraint information and generating a database definition incorporating the data constraint information.

Further, the present invention provides constraint information input means for inputting constraint information relating to the entity or its relation corresponding to a method when the entity in the entity relation model is associated with a class in object orientation, and the constraint information input. Storage means for storing the constraint information input by the means, and data constraint information adding means for converting the constraint information and incorporating it as data constraint information in a database definition corresponding to the entity-relationship model that is generated in advance. The data constraint information adding device is provided.

[0010]

In the present invention, the entity-related constraint information input means relates to the entity information in the entity-relationship model, the relevant information of those entities, and the entity or the association corresponding to the method when the entity is associated with the object-oriented class. The constraint information and the constraint information are respectively input, and the storage unit stores the entity information, the related information, and the constraint information input by the entity-related constraint information input unit. Then, the database definition generating means converts the entity information, the related information, and the constraint information to generate a database definition including the data constraint information.

Further, according to the present invention, the constraint information input means corresponds to the method when the entity in the entity relation model is associated with the object-oriented class,
Constraint information regarding an entity or its relation is input, and the storage unit stores the constraint information input by the constraint information input unit. Then, the data constraint information adding means converts the constraint information and incorporates it as data constraint information into the database definition corresponding to the entity-relationship model that is generated in advance.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the principle of the present invention will be described below while explaining the entity-relationship model, the object-oriented language, and their relationships.

ER as an integrated model that also absorbs the idea of relational model, network model and binary relation by using two elements, entity description and relationship between events An entity-relationship model has been proposed (see Information Processing Handbook, pp 671-672, Information Processing Society of Japan). The model has good comprehension of the model itself and good correspondence with the semantic information structure of the real world.

In the ER model as well, the model is such that the entity relation level, the information structure (attribute description) level of each entity and the relation, the data structure level independent of the access path, and the 4 level of the dependent data structure. I am thinking about the level of conversion. The basis of this model is to clearly separate information about entities and information about relationships between entities at the first level. At this level, the entities are rectangles and the relationships are the connections between the entities.
It is represented by a diagram such as.

When the types and uses of entities and relationships are determined, attributes required for each entity and relationship are assigned (FIG. 3).
The entity-relationship (ER) diagram thus obtained actually corresponds well to the structure of data defined in natural language.

FIG. 4 is a diagram showing another entity relation model.

On the other hand, the concept of object-oriented language is also known. There, a "class" of an object-oriented language can be considered as a counterpart of the "entity" of the entity-relationship model. Also, classes can be defined hierarchically. For example, in the case of the entity-relationship model of FIG. 4, "manager" and "non-manager" are subclasses of "employee".
Can be defined as a subclass of "book", "manual" or "magazin"
e) ”can be defined. A class is a generic abstraction of individual data (instances). For example,
Each "employee" is a class "employee"
e) ”. In object-oriented languages, procedures are called methods. In the definition of a procedure (method) in an ordinary programming language, the type of its argument is specified. Similarly, in the object-oriented language, the class of the argument that the method takes is specified. The point that is different from the procedure of a normal programming language is that the method of the same name can be defined if the argument class (set) is different. In addition, the descendant class inherits all the properties of the superior class (including the methods defined for the class). Therefore, even if a method is not directly defined in a certain class, that method will be called if it is defined in its superordinate class. For example, the class "employe
e) ”is a method to ask for that salary“ salary (salar
y) ”is defined (method 1), and its subclass“ manager ”has a method with the same name (but different content) defined (method 2). .. At this time, "management (manage
r) ”instance as an argument to“ salary ”
If is called, method 2 is called and executed. When "salary" is called with an instance of "non-manager" as an argument, "salary" is directly sent to "non-manager".
ary) ”is not defined, so the upper class“ employee (e
Method 1 defined for "mployee)" is called and executed.

When a method takes a plurality of arguments, the same mechanism as above operates, and such a method is called a multiple method.

Therefore, the data constraint described in the prior art is
It can be considered that it corresponds to the method in such an object-oriented language.

FIG. 5 is a block diagram showing an embodiment of the database definition generating apparatus with data constraint information according to the present invention.

The entity-relationship constraint information input means 1 includes entity information in the entity-relationship model, relational information of those entities,
This is a means for inputting the constraint information about the entity or the association, which corresponds to the method when the entity is associated with the object-oriented class. For example, in the case of the entity relation model as shown in FIG. 4, the entity information is “employee”,
"Management", "non-management", "books", "magazines",
It is a "manual", and related information is "age" attribute information of an employee, "check-in date", and "check-out date" is "rent" attribute information. Here, the two one-to-many relationships are treated as many-to-many relationships (the same applies when the intermediate entity has attributes). Considering the data constraint information for each entity and association of such entity-relationship model, for example, they are as follows.

Constraints Example 1: For actual employees ・ ・ ・ Age <60 Constraints Example 2: Related For borrowing [employee, book] ・ ・ ・ ・ ・ Check-out date-Check-in date <10 Constraint example 3: For related borrowing [manager, book] ・ ・ ・ ・ ・ Check-out date-Check-in date <20 Constraint example 4: Related For borrowing [non-manager, manual] ・... Check-out date-Check-in date <15 Assuming that the entity is an object-oriented class and the constraint is a kind of method as described above, consistent inheritance of data constraints based on a hierarchical structure is considered. Can be realized.
Here, the data constraint defined for the relation is expressed as a multiple method having two entities (classes) in which the relation is defined as arguments (the inheritance mechanism of the multiple method is CL.
It is realized by OS etc.). Considering the constraint examples 2, 3, and 4, the generic function “borrow” is defined,
A method is defined that takes a set of each entity as an argument. The hierarchical structure is as shown in FIG. If no direct constraint is defined, the closest applicable constraint (highest priority) is chosen. For example, constraint 4 is applied to the set of entities [manager, manual] because no direct constraint is defined.

To repeatedly describe, 1. In the entity-relationship diagram, describe the data constraints that should be established for each entity and association.

2. Think of an entity as a class in object orientation.

3. Think of data constraints as methods in object orientation.

At this time, the name of the method is "" when the constraint is defined for one entity.
self "when the constraint is defined for an association,
Let it be the related name. The argument of the method is the entity name when the constraint is defined for one entity, and the entity name when the constraint is defined for one association.
The names of the two entities for which the association is defined.

For example, the method corresponding to the above constraint example 1 has a method name of "self" and an argument of an employee class. In addition, the method corresponding to the constraint example 2 has a method name of borrow (borrow), and an employee (employee),
It takes two classes called books as arguments.

Many kinds of data constraints are often defined according to the entity to which the data belongs. At this time, which constraint should be applied can be obtained by executing the method having the same name as the relation in which the constraint is defined.

Based on such an idea, the constraint information is specified, and the keyboard, mouse,
Input using the display and other input devices. Of course, at that time, the database definition generating means 3 described later
Input according to a predetermined rule that can be converted by.

The storage means 2 is a device such as a RAM or a magnetic disk, and stores the input substantive information, related information and constraint information.

The database definition generating means 3 is a database definition generating tool such as Backman (product name), ADW (product name), etc., and stores the entity information, related information and constraint information stored in the storage means 2. It is a means for converting and generating a database definition in which data constraint information is incorporated. Converting entity information and related information to generate a database definition is a conventionally known technique, but similarly, constraint information can be added.

Reference numeral 5 is a data input means such as a keyboard for inputting data. With this data input means 5, the operator inputs the age, check-out date and the like. Reference numeral 6 denotes the data input from the data input means 5 and the above-mentioned database definition generating means 4
It is a database generation means for inputting a database definition in which the data constraint information is generated generated by, and checking the validity of the input data while referring to the data constraint information to complete the database.

FIG. 7 is a block diagram showing another embodiment of the data constraint information adding device of the present invention.

The database definition storage means 10 is a means such as a RAM or a disk for storing a database definition generated in advance for a predetermined entity-relationship model as in the embodiment of FIG. 1 or by a known method. Is.

On the other hand, the constraint information input means 7 is a means such as a keyboard, a mouse, a display, or the like, which can input constraint information about an entity or its relation in the entity relation model. The constraint information input means 7 allows input of constraint information to be added (added) to the database definition stored in the database definition storage means 10.

The storage means 8 is a means such as a RAM or a disk for storing the constraint information input by the constraint information input means 7.

The data constraint information adding means 9 is a storage means 8.
Is a means for converting the constraint information stored in the database definition storage means 10 and incorporating it as data constraint information in the database definition of the database definition storage means 10 corresponding to the predetermined entity-relationship model.

The present invention can be applied to a relational database which is widely used at present. Specifically, when a field in the table is updated or inserted in the program, it can be determined which of the declaratively defined data constraints (apart from the program) should be checked. However, in this case, it is necessary to divide the hierarchical structure generated by the present invention into fields to be updated and inserted. In addition, it is necessary to consider that the hierarchical structure can be realized in various forms in the relational database (use of foreign key, setting of identification field, etc.).

Each means of the present invention may be realized by software using a computer or by using a dedicated hardware circuit having those functions.

[0041]

As is apparent from the above description, according to the present invention, when a data constraint is applied to a database definition, a database definition generating device with data constraint information in which a programming error in the conventional method does not occur. It is also possible to provide a data constraint information adding device.

[Brief description of drawings]

FIG. 1 is a diagram showing a partial configuration of a database.

FIG. 2 is a diagram showing an entity relationship model.

FIG. 3 is a diagram showing an entity relation model.

FIG. 4 is a diagram showing another entity-relationship model.

FIG. 5 is a block diagram showing an embodiment of a database definition generation device of the present invention.

6 is a diagram showing a relationship of constraint information of the entity-relationship model of FIG.

FIG. 7 is a diagram showing another data constraint information adding device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Entity-related constraint information input means 2 Storage means 3 Database definition generation means 4 Storage means 5 Data input means 6 Database generation means 7 Constraint information input means 8 Storage means 9 Constraint information addition means 10 Storage means

Claims (2)

[Claims] 1. Entity information in an entity-relationship model, related information of those entities, and constraint information relating to the entity or the association, which corresponds to a method when the entity is associated with a class in object orientation, can be input. Entity-related constraint information input means, storage means for storing the entity information, related information and constraint information input by the entity-related constraint information input means, and converting the entity information, related information and constraint information, A database definition generating device with data constraint, comprising: a database definition generating means for generating a database definition incorporating data constraint information. 2. Constraint information input means capable of inputting constraint information relating to the entity or its relation, which corresponds to a method when the entity in the entity relationship model is associated with a class in object orientation, and the constraint information input means. A storage unit that stores the constraint information, and a data constraint information adding unit that converts the constraint information and incorporates it as data constraint information into a database definition corresponding to the entity-relationship model that is generated in advance. Characteristic data constraint information adding device.