JPH0264768A - Index system for data file - Google Patents

Abstract

PURPOSE:To attain order-calling in the inverse direction by making the whole data record as an key data item and providing a second index file to have a corresponding table with second key data of inverse order corresponding to a first key data to be ascending order. CONSTITUTION:By an instruction from a CPU (p), data and key data bi are written in an index file (f). Then, data bi are set to an index part in ascending order, key data bi' are prepared from the data bi, and the data bi and bi' are written as a corresponding table in the index file f''. Next, when the data are order-called, the CPU (p) sets the initial key data bi, calls the file (f) and reads the data corresponding to the data bi. The data can be read in ascending order with repeating it. Next, when the inverse order-calling of the data is executed, the CPU (p) sets the data bi', calls the file f'' and reads the data bi corresponding to the data bi'. Then, the file (f) is called based on the data bi, and data ai corresponding to the data bi are read.

Description

[Detailed Description of the Invention] [Summary] Contents of an indexed data file using an indexing method for a data file configured such that part or all of the data is defined as key data and a data record corresponding to the value of the key data is called arbitrarily. To provide a data file indexing method that enables sequential recall in the reverse direction by a simple method on the user side even in a computer system in which the size of key data for indexing cannot be recalled in the reverse direction. For the purpose of A second index file having a correspondence table between the key data and the second key data in reverse order corresponding to the key data is configured.

[Industrial application field]

The present invention relates to a data file indexing system in which part or all of the data is defined as key data and a data record corresponding to the value of the key data is arbitrarily called.

As a method of managing data using a computer system,
There is a method of managing each data file, which is a logical group of data.

The data file may also be organized according to several organizational methods depending on how the records in the data file are accessed.

One of these organization methods is the index order organization method, in which a key that identifies the records that make up the data file is entered in a certain field of each record, and the records arranged in the order of the key value are called. It is.

On the other hand, with the spread of online processing using computer systems, opportunities to search for data from CRT display terminals and the like are increasing.

When calling data records in a data file using an index file based on the index sequential organization method, for example, data is searched from a CRT display terminal, etc., and the data displayed before the currently displayed data is retrieved. If you want to go back and look at the data file, you need to search and display the data file again, but depending on the type of computer system that uses the above index ordering method, there are some things that cannot be searched backwards. be.

In order for a user of such a computer system to be able to perform a backward search using a simple method, a data file indexing method that can be handled by the user is required.

[Conventional technology]

FIG. 6 is a diagram for explaining a conventional example, and FIG. 7 is a diagram for explaining another conventional example.

The indexed data file (f) (hereinafter referred to as the index file) defines a part of the data record in the data section (d) as a key data item (C), as shown in FIG. 6(B). It has an index part (il) that forms a data record only with the key data item (C1) in (d).

Also, the data part (each record in dl is each data a3.af
+al, . . . and the key data items forming part of the leading part (key data b,, b,, b, in C1).

It consists of...

On the other hand, the record in the index part (1) is created by the command of the control part (hereinafter referred to as CPU) (p) shown in FIG.
For example, they are organized and set in order from the smallest number.

Now, when searching for data in the index file from a CRT display terminal (not shown), the CRT display terminal (not shown) is used.
6th due to request to read data from RT display terminal.
As shown in FIG.
, . . . in order, reads the data record in the data section fdl containing the key data b, and reads the data a3 .
a2. a3. ...is displayed.

In the conventional example described above, if you want to read the data records in the data section tdl including the key data b, and go back and view the data records earlier than those displayed on the CRT display terminal (not shown), read the index file (f) again. ), which makes the search procedure more complicated.

Therefore, a computer system has been realized in which an index file (f)' as shown in FIG. 7 is organized.

That is, a new key data item (C1' (provided in the index part (1)') is added to a part of the end part of the data record in the data section fdl, and the key data is added to the first key data item (C1's The size relationship of key data is bl<b2<b
, <, ..., <b,%, this key data b,, b2 . b, ..., corresponds to b7,'
>b2 Create key data such that '>b, '>, ..., >b' and enter this key data item (C
)′ in ascending order, it is also possible to index in reverse ascending order.

[Problem to be solved by the invention]

However, depending on the type of computer system, there are some that do not have the index file (f)' explained in FIG. However, if you wanted to perform a sequential call in the reverse direction, you would have to have another computer system, which would be uneconomical.

The present invention makes it possible to perform sequential calls in the reverse direction using a simple method on the user's side, even in computer systems that cannot perform backward calls based on the size of key data used to index the contents of an indexed data file. The purpose is to provide an indexing method for data files.

[Means to solve the problem]

FIG. 1 shows a block diagram illustrating the invention in detail.

(f) in the block diagram of the principle of the present invention shown in FIG. 1 is a first index file having a part of a data record as a key data item, and first key data b having ascending numbers; (“Bi takes all of the data records as key data items,
The second key data b in reverse order corresponds to the first key data b in ascending order.
This is a second index file that has a correspondence table with key data b, ', and when sequentially calling data record strings, the first key data b, in the first index file (f) is indexed in ascending order. If the data record string is called in reverse order, the second key data b' in the second index file (fl'' is sequentially called and the corresponding first key data b4 is determined. This is a means to solve this problem by indexing the information.

[For production]

When the first index file (f) configures an indexed data file in which the key data item in the data area is used as an index, the first key data is < bz <
If bz <,..., b7, the first key data b,, b2 . ..., the second key data corresponds to bn, '>b,'>b.

〉, ..., >ba' key data item (
A second index file having a correspondence table of C-bi (constituting f-bi, usually the first key data b,, b2゜..., bn
are called in ascending order, and the first key data b, , b2 .
..., when calling b7 in reverse order, the second key data is b I'+b2'+b3...,b
,,' in ascending order, the second index file ('pi) corresponds to the first key data b,, b2, .
, b7 can be called in reverse ascending order.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 2 to 5.

FIG. 2 is a diagram explaining the present invention in detail, FIG. 3 is a diagram explaining a processing flowchart at the time of data writing in an embodiment of the present invention, and FIG. 4 is a diagram explaining the process of sequentially calling data in an embodiment of the present invention. Diagram explaining the flowchart, No. 5
The figures each show a flow chart for explaining a processing flowchart for calling data in reverse order in an embodiment of the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

In the embodiment of FIG. 2, an index file ([1, All are key data items (C1, (C)“
An index file ("
This is an example of a case where it is configured with

Also, the first key data b1 explained in FIG. 1 is the same as the first key data b1 explained in FIG. 6. b3. ..., b7,
The second key data b1' is determined by its size, '>b
,'>b3'>, ...,>b7', and the first
The key data b, , b, .

That is, bl and b+'+ bl and b2, b, and b3'
,..., bn and b7' correspond, and b l
+ b2 Z b3+ ...'+ bn' is.

b2. b, ..., bo in reverse ascending order.

The processing flowcharts shown in FIGS. 3 to 5 are executed by the CPU (p
The index file (f) shows the index processing procedure under the control of i.
Data writing to the index file (f) is processed as shown in FIG.

That is, first, data a8 and key data b are written into the index file (f) by a command from the CPU (p). Then, the key data b is set in the index section (1) in ascending order, and the key data bl' is set from the key data b to the key data bl'
Create the key data b, and b to the index file (f)''
Write i' as a corresponding table.

Next, when sequentially calling data, CPU fp)
sets the initial key data b, calls the index file (f), and reads out the data a corresponding to the key data b. By repeating this, data a,
can be read out.

Next, when performing a reverse order call of data, cpU(ρ)
sets the initial key data b i ', calls the index file (f bi, and reads the key data b corresponding to the key data b,'. Then, calls the index file (f) based on the key data b, Read data ai corresponding to key data bi.

By repeating this in the ascending order of the key data b i ', the same process as calling the key data b in the reverse order is performed.

By processing as described above, data can be retrieved freely in ascending order and descending order even if the computer system has an index file in which reverse order recall is not possible and the key order is limited to ascending order. can be processed efficiently.

〔Effect of the invention〕

According to the present invention as described above, it is possible to organize an index file in which a user can freely retrieve data in ascending order or descending order in a computer system having an index file in which data indexing by keys is limited to ascending order. , data searches can be processed efficiently.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the present invention in detail, FIG. 2 is a diagram explaining the present invention in detail, FIG. 3 is a diagram explaining a processing flowchart at the time of data writing in an embodiment of the present invention, and FIG. 5 is a diagram illustrating a processing flowchart for sequential data recall in an embodiment of the present invention, FIG. 5 is a diagram illustrating a processing flowchart for reverse data recall in an embodiment of the present invention, and FIG. 6 is a diagram illustrating a conventional example. 7 and 7 are diagrams illustrating another conventional example, respectively. In the figure, al is data, b,,b,' are key data, (dl, (dbi is data part, (C1, (C)', (C)" are key data items, ([1, (f )' , (fbi is an index file,
(11, (1) ', (11' indicates the index section, and (ρ) indicates the CPU. 3 (1 data letter sending B odd α
Figure 3 (Index file) (C) (Key data item) Diagram explaining the conventional example

Claims (1)

[Scope of Claims] A computer system in which key data for identifying data records to be recorded in a data file is defined in a certain field of each data record, and the key data is used to index and call a series of data record columns in ascending order. a first index file ((f)) having first key data (b_i) having ascending numbers in which part of the data record is a key data item; and all of the data record is a key data item; Second key data (b_i) in reverse order corresponding to the first key data (b_i) in ascending order
The second index file ((
f)''), and when the data record strings are sequentially called and indexed, the first key data (b_i) in the first index file ((f)) is indexed in ascending order. When the data record string is called up and indexed in reverse ascending order, the second
A data file characterized in that the first key data (b_i) is indexed in reverse ascending order by calling the key data (b_i') in ascending order and determining the corresponding first key data (b_i) at that time. indexing method.