JPH03210667A - Access method to information having same key - Google Patents

Abstract

PURPOSE:To efficiently ensure an access to a data base by adding the additional conditions to a key part to fractionize the deciding conditions and recording the Nos of subsequent data into a data part. CONSTITUTION:When plural data are designated by the deciding conditions 22A which designate the information to receive an access, the conditions 22A are fractionized by the additional conditions 22B and plural data are available with the same key. When an access is given to the data designated by the conditions 22A, a subsequent data designating area 23A is read out of the data and the subsequent data No written in the area 23A is designated as the access conditions as long as the data No is written. Thus the next access is carried out. Meanwhile the next processing is carried out when no data No is written in the area 23A. Thus the presence or absence of the data that are designated by the same key can be decided without reading the next data. Then an access is efficiently applied to a data base.

Description

[Detailed Description of the Invention] [Summary] Regarding a method of accessing a keyed file in a system in which a database is constructed using keyed files, the present invention enables the existence of multiple pieces of data with the same key, and the existence of multiple pieces of data with the same key. The purpose is to provide a method for accessing information with the same key that allows efficient searches of multiple data, and allows for multiple data to be specified by the decision condition that specifies the area to be accessed in the key part. If there is an additional condition for making the decision condition, and if there is subsequent data specified by the same decision condition in the data section, a subsequent data specification area is provided to record the data number, and if there is more than one data specified by the decision condition. Sometimes, the decision condition is subdivided with additional conditions to enable the existence of multiple data with the same key, and when accessing the data specified in the decision condition, the subsequent data specified area in the data is read and the data number is is written, the next access is made by specifying the subsequent data number stored in the subsequent data specification area as an access condition, and when no data number is written in the subsequent data specification area, the next access is made. Configure it to perform the following processing.

[Industrial application field]

The present invention relates to a method for accessing keyed files in a system in which a database is constructed using keyed files.

With the advancement of computer systems, databases have been widely adopted.

One of the files used in databases is a keyed file, which consists of a key part and a data part written in the area specified by the key part. is a one-to-one correspondence.

In such a keyed file, there is a need for a keyed file access method that allows multiple data to exist with the same key and that reads the multiple data efficiently.

[Conventional technology]

Figure 5 is an easy-to-understand example of a conventional keyed file↓
It is a diagram.

The conventional example shown in FIG. 5 has two keyed files 21a and 2.
1b, keyed file file 2
Based on the information in 1a, the corresponding information in the keyed file 21b is allocated.

For example, the keyed file 21a indicates that the decision condition is A.
, A', A'', data a, a', a' are read out in accordance with the conditions.

In such a keyed file, multiple pieces of information are not allowed to exist for one physical key.

Therefore, in order to enable the existence of multiple data for one condition, the keyed file 2 in (b)
By increasing the length of the key part 22 as shown in lb' and adding data-specific numbers such as 1, 2, 3, etc. after the decision condition SB, for example, the key part can be made unique. It has a sexuality.

[Problem to be solved by the invention]

In a keyed file, the key part 22 must be unique, so in order to have multiple pieces of data for one decision condition, the length of the key part 22 should be made long and only the decision condition In addition to the key,
Adding conditions to subdivide the decision conditions makes it unique.

However, changing the key length and re-creating a database that has already been constructed and is in operation requires a large amount of man-hours.

The present invention enables the existence of multiple data with the same key,
Another object of the present invention is to provide a method for accessing information having the same key, which allows efficient searching of multiple pieces of data with the same key.

[Means to solve the problem]

FIG. 1 shows a detailed illustration of the invention.

(a) of the principle block diagram of the present invention shown in FIG. Key part 22 constructed in
and a data section 23, 22A is a determination condition of the key section 22 that determines the access condition, 22B is an additional condition provided in the key section 22 to subdivide the determination condition 22A, 23A is a subsequent data designation area provided in the data section 23 in which the number of subsequent data following the accessed data is written, and providing such means is a means for solving this problem.

[For production]

An additional condition 22 that subdivides the determination condition 22A in order to allow multiple pieces of data to exist in the determination condition 22A of the key part 22.
By using the key section 22 in which B is provided, it is possible to have multiple pieces of data under the same decision condition 22A, and when accessing the keyed file 21, the data section 23
When the subsequent data specification area 23A is read and a data number is written, the subsequent data number written in the subsequent data specification area 23A is specified as an access condition, the next access is made, and the subsequent data specification area is read. When the data number is not written in 23A,
By performing the following processing, the presence or absence of data specified by the same key can be determined without reading the next data.
It becomes possible to efficiently access the database.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 2 to 4.

Fig. 2 is a diagram explaining a keyed file according to an embodiment of the present invention, Fig. 3 is a diagram explaining an access method according to an embodiment of the present invention, and Fig. 4 is a diagram explaining a processing flowchart according to an embodiment of the present invention. Figures are shown for each.

Note that the same reference numerals indicate the same objects throughout the figures.

The embodiment of the present invention shown in FIG. 2 shows an example of a keyed file 21 used in a production management system.

For example, when manufacturing a certain device, it is necessary to arrange the parts that make up the device. Such necessary parts are constructed as a database, and part information is written in a keyed file 21.

Here, three parts a1 to a3 whose part type is S specified by condition A are written, and part a2 exists in the subsequent data specification area 23A of part a1, so 002 is written for part a2. In the subsequent data designation area 23A, part a3
exists, so 003 is written, and part a3
The subsequent data designation area 23A is blank because there are no subsequent parts.

Here, the determining condition 22A is A, and since there are three pieces of data under the same condition, in order to distinguish them, the additional conditions 22B are set as Sl, S2, and S3.

FIG. 3 shows a method of accessing the keyed file 21 explained in FIG. 2, in which the decision condition A is retrieved from the keyed file 21A, and data is first assigned to the keyed file 21B for the part type S. .

Next, the keyed file 21B is allocated for the part type T of the determination condition A.

After the search for determination condition A is completed, a search is performed for determination condition B, and then a search for condition C specified below is performed.

Here, data a l Sa 2, a3 for component type S for determination condition A, data a for component type T for determination condition A, data b for component type S for determination condition B, and data b for component type T for determination condition B. does not exist, so next we search for part type S with decision condition C, and after confirming that it does not exist, we search for data cl,
c2 is searched.

FIG. 4 is a flowchart of the process.

■ Read the conditions for accessing the keyed file 21B from the keyed file 21A. Here, it is assumed that the information is read in order from the top, and the decision condition A is read out.

■ First, a search is performed for part type S, so (S+A) is set as the determination condition.

(2) Read the keyed file 21B according to the conditions (2).

(2) Read the data in the subsequent data designation area 23A and determine whether there is any subsequent data.

■ Here, since "2" is written, it indicates that the second data of the succeeding data exists, so set the access condition (cow) to (S+2+A) and search for the data following ■. .

■ When the subsequent data specification area 23A is blank, it indicates that the search for the part type S for the decision condition A has been completed.
A search is executed for the part type T to the determination condition.

As described above, by configuring a keyed file, it is possible to have multiple pieces of information with the same key, and the number of subsequent data is recorded in the data section (this makes it possible to efficiently access the database. It becomes possible to do this.

[Effects of the Invention] According to the present invention as described above, by adding additional conditions that subdivide the determination conditions to the key part, it is possible to have multiple pieces of information with the same key, and the data part can contain subsequent data. By recording the numbers, it becomes possible to provide a method for accessing information having the same key that allows efficient access to the database.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining the present invention in detail, FIG. 2 is a diagram explaining a keyed file according to an embodiment of the present invention, FIG. 3 is a diagram explaining an access method according to an embodiment of the present invention, 4 is a diagram illustrating a flowchart of processing according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating a conventional keyed file. In the figure, 10 is a processing device, 20 is a magnetic disk, and 2I, 21A, 21B, 21a. b' is a file with a key, 22 is a key part, 22A is a decision condition, 22B is an additional condition, 23 is a data part, 23A is a subsequent data designation area, 30 is a terminal device, and 40 is a printer. (bl Detailed explanation of the present invention) Figure 1: Detailed explanation of the keyed file of the embodiment of the present invention Figure 2: Opening of the access method of the embodiment of the present invention Fig. 4 for explaining the flowchart Fig. 5 for explaining the conventional keyed file

Claims (1)

[Claims] A key configured on the magnetic disk (20) of a data processing system consisting of a processing device (10), a magnetic disk (20), a terminal device (30), and a printer (40). A method of accessing a database using an attached file (21), which includes a key part (22) that specifies the area to be accessed, and a data part (23) written in the area.
), an additional condition (22B) for allowing a plurality of data specified by the determination condition (22A) specifying the area to be accessed to exist in the key part (22); The same determination condition (22A) is stored in the data section (23).
), a subsequent data specification area (23A) in which the number of the data is recorded.
and when there is a plurality of data specified by the determination condition (22A) specifying the information to be accessed, the additional condition (22A) is set.
In step 2B), the decision condition (22A) is subdivided to enable the existence of multiple pieces of data with the same key, and the decision condition (22A) is
When accessing the data specified in A), the subsequent data specification area (23A) in the data is read, and if a data number is written, the following data specification area (23A) is accessed as an access condition. Having the same key, the next access is made by specifying the written subsequent data number, and when the data number is not written in the subsequent data specification area (23A), the next processing is performed. How to access information.