JPH0535791A - Retrieving sequential file - Google Patents

Abstract

PURPOSE:To shorten retrieval time when retrieving in large amount, relating to sequential files. CONSTITUTION:A file control part 3 reads, under instruction from an upper- priority device, a sequential file 4 and generates or deletes a temporary index key file 5, and in addition, controls the sequential file 4 and the temporary index key file 5 so as to realize index retrieval. Therefore, when retrieving in large amount, wasteful processings are limited to minimum and retrieval time comes to be short consequently, high efficiency is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for searching a sequential file having no index key in a computer system.

[0002]

2. Description of the Related Art In a conventional sequential file search method,
When a search request occurs, read the data stored in the sequential file from the beginning, check whether it is the required data, and find the required data.
I was repeatedly reading and inspecting.

Even when a new search request is made, the same processing as described above is repeated.

[0004]

In this conventional sequential file retrieval method, unnecessary data is read in order to perform a single inspection, and when a large number of retrievals are made, this error is not read. There is a problem that the required processing increases, the efficiency is very low, and the search time also increases.

[0005]

SUMMARY OF THE INVENTION A sequential file search method according to the present invention is a sequential file of a search key portion and a data storing an index key required for an index search in response to a sequential file search request. It is characterized in that a temporary index key file having two areas of an address part indicating a position in is created and then the sequential file is index-searched using this temporary index key file.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. The higher-level device 1 is a computer system, and the file control unit 3, the sequential organization file 4, and the temporary index key file 5 exist on the magnetic disk 2 connected to the higher-level device 1.

Next, the operation of this embodiment will be described.

When a request for an index search in the sequential file 4 is made, the host device 1 issues a command to create a temporary index key file 5 to the file controller 3. Then, the file control unit 3 receives all the instructions, reads all the sequential files 4, and uses any item of the sequential file 4 as a key, and uses two items, that is, a search key section and an address section indicating the position of the data in the sequential file. Create a temporary index key file 5 with areas,
After the creation is completed, the higher-level device 1 is notified. After receiving the notification, the higher-level device 1 issues an index search instruction to the file control unit 3, and the file control unit 3 controls the sequential file 4 and the temporary index key file 5 to check the sequential file 4 for an index. Then, the search result is notified to the higher-level device 1.

Further, when the request for the index check disappears, the higher-level device 1 notifies the file control unit 3, and the file control unit 3 releases the temporary / index key file 5 and, after the end, sends it to the higher-level device 1. Notice.

[0011]

As described above, according to the present invention, when it becomes necessary to search the index of a sequential file, a temporary index key file is created using any item as a key, and the index search is performed on the sequential file. Since it is possible to perform the above, it is not necessary to perform the search for reading the data of the sequential file sequentially from the beginning as in the conventional case, and when performing a large number of searches, compared to the conventional technology, It has an effect that a search can be performed in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Upper device 2 Magnetic disk 3 File control unit 4 Sequential file 5 Temporary index key file

Claims (1)

What is claimed is: 1. A search key part storing an index key required for an index search in response to a search request for a sequential file, and an address part indicating the position of data in the sequential file. A method for searching a sequential file, wherein a temporary index key file having one area is created and then the sequential file is index-searched using this temporary index key file.