JPH0728683A - Database system - Google Patents

Abstract

(57) [Summary] [Purpose] For a specific item, determine the data that is the true value, and improve the reliability of the database system. [Structure] In terms of hardware, it is composed of a host computer 1, a terminal 2, and a database 3. Database management system 2 and application program 3 as software
There is. True value judgment function 3 in database management system 2
Is provided, and the true value judgment of data at the time of retrieval is performed by this function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for computer edit design (CAE system) in various industries. The present invention relates to a computer system having one or a plurality of databases.

[0002]

2. Description of the Related Art Conventionally, when searching data from a database, after specifying a search condition by a logical expression and selecting a file as a search target, a record realization value including the data is found, and a necessary value in the record is found. It's a common practice to pick out such fields.

When there are a plurality of files to be searched,
Select the record of one file by the above method and combine the records of other files related to it (j
It can be retrieved by operations such as oin) or cross referencc.

Further, the conventional method for checking the validity of data is
There are format check, type check, value check, and balance check. , Is a check as to whether the number of digits of data and the type of data (alphanumeric characters, kana characters, etc.) are as defined, and this is performed by the database management system when normal data is input to the database. Is a check to see if the value is meaningless even if the data format and type are correct, and a limit check is performed. Is a logical check that the value of a specific item has a relationship with the content of another item, and when one value changes, the other item must be changed in connection with it. , Is usually outside the scope of a database management system, and often creates application programs written in general-purpose programming languages to add these functions.

[0005]

SUMMARY OF THE INVENTION In the above prior art,
A file that creates a logical check, such as a balance check, or an index, such as a transposed file, when you try to update some data, to change the associated data at each level, such as other databases, files, records or fields. Was used to update the data. However, in the balance check,
Data that is logically irrelevant or could not be associated cannot be changed. It was also found that the transposed file requires an extra storage space, which makes maintenance of the index a burden in an environment where data is updated frequently. As a result, when the data of a certain item is retrieved by searching, for the true value for that item,
There is a problem that there is data with different values from the true values and it is difficult to know which is the correct data.

An object of the present invention is to improve the reliability of the database system by determining the data having a true value for such a specific item.

[0007]

In order to achieve the above-mentioned object, according to the present invention, when a plurality of data of different values are retrieved with respect to one true value by search, they are set to the retrieved data. The data management system is provided with a routine for confirming the presence or absence of a flag indicating locking and, if present, determining the data as a true value.

When a plurality of processes (tasks) use the database at the same time, the processes are locked to prevent loss of data consistency due to double update. There are two types of locking: an exclusive one for updating data and a common one for reading data. Co-locked processes are allowed to use the database concurrently, but exclusive and other locked processes are not allowed to be used simultaneously. At the same time, it is possible to impose a use restriction (exclusive lock) by the user LD or a password on a process or user that can be updated on the data side as well. Therefore, the flag set to the above-mentioned data, which means the lock, means that the user ID or password attached to the data group or the item is read by the data management system to clarify that the data is the locked data. Of the data retrieved by the search,
It is obvious that the data having such a flag has priority over the data having no flag. Therefore, it can be determined that the data having the flag is a true value.

It is also possible that a plurality of data among the retrieved data having one true value are locked. In this case, it is necessary to determine in advance which process or user the data item should be updated with, or to convert the logical quantity into data so that a logical judgment can be made automatically. The data to be set can be determined.

[0010]

In the data system, locking data or processes (tasks) to prevent double updating of data is
It is a common practice. In the present invention, since the locked status is used to determine which of the retrieved data is the true value, it is possible to add the determination data at the time of data input simply by reading the data. Absent. Therefore, an event such as an increase in data length or alteration of contents due to data processing does not occur.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the embodiment will be described below with reference to FIG.

The database system according to the present invention is composed of a host computer 1, a terminal 2, and a database 3 in terms of hardware. In some cases, it may be possible to exchange data with another database system 8 via a communication circuit via the modem 7. Such a hardware configuration is the same as that of the conventional database system as shown in FIG.

In terms of software, in the conventional data system, as shown in FIG. 2, data processing is performed by the database management system 2 and the application program 3. Seen from the role of data processing, the application program 3 performs data processing such as data addition, deletion, update, read, and search, whereas the database management system 2
In the above, processing such as checking the validity of the usage right among the user / terminal / application program / database, monitoring the access status, and maintaining and managing the database is carried out. In the present invention, the true value judgment function 1 is added to the function of the database management system 2.
The true value judging function 2 judges which data is the true value when a plurality of data having different contents exist for one true value when the data regarding the specific item is retrieved by the search.

The determination method checks whether or not the data is exclusively locked, and considers that the data is exclusively locked as being close to the true value. The determination procedure will be described below with reference to FIGS.

FIG. 3 shows the level of locking the data. A group of data is composed of a single record, a group of records, a file, a group of files, a volume and a group of volumes in order from the smallest unit. Locking is applied to each group of these levels. Locking can be either exclusive or shared. This is either exclusive (updatable) or shared (read only) for the process (task) user or application program that is trying to access certain data. ) Is checked by a password or the like. Therefore, by specifying what is exclusive access (general term for processes, users, etc.) and selecting the most upstream or highest priority access to the data to be obtained by the search, the multiple extracted by the search Among these data, one data having an exclusive lock for the selected access can be arbitrarily determined. FIG. 4 shows the above flowchart.

The choice of the most upstream access or the highest priority access can be made by human input, but the access can also be selected from the search conditions by using rule-based reasoning or the like.

[0017]

According to the present invention, the reliability of the data is improved because the data extracted by the search is determined as one true value. In addition, for data that is determined not to be a true value, there is an advantage that an announcement that the data is not a true value allows the data to be separately corrected to a true value by exclusive access. Adding such a function can not only improve the above-mentioned effects but also improve the quality of data as a whole database system.

[Brief description of drawings]

FIG. 1 is a block diagram of a database system according to the present invention.

FIG. 2 is a block diagram of a conventional data system.

FIG. 3 is an explanatory diagram of a data structure.

FIG. 4 is a flowchart of true value determination.

[Explanation of symbols]

1 ... Host computer, 2 ... Database management system, 3
… Application program, 4… True value judgment function, 5… Terminal, 6…
Database, 7 ... Modem, 8 ... Another database system.

Claims (1)

[Claims] 1. A database management system for performing one or a plurality of databases, adding, deleting, updating, reading and searching of data stored in these databases and security management of the data, and accessing the data. In a system consisting of a terminal device, when data related to a specific item is retrieved by search, if there are multiple different data contents, a function to determine which data is the true value by setting a flag in the data A database system characterized by being provided in the data management system.