JPH0498331A - Retrieval system for unused record of data file - Google Patents

Abstract

PURPOSE:To shorten processing time at the time of adding data in a data file by retrieving a record where data on the data file is eliminated from key information which is read and writing data into the record. CONSTITUTION:An application program and a file control 3 control a file 1 and a file 2. At first, data on the file 1 is eliminated by an arrow (1) and elimination information is written into the file 2. Key information corresponds to the address of the data file 1. Then elimination information are sequentially read from the head of the file 2 and the unused record of the file 1 is directly retrieved by key information of elimination information which is read and data is added. Then, the file control 3 eliminates head elimination information in the file 2. Thus, processing time at the time of adding data, namely, the access time of the unused record in the data file can be shortened.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for searching for unused records in a file storing data in an information processing device, in particular a method for searching without accessing a file storing data, processing when data is added to a data file. In order to shorten the access time for unused records, in an unused record search method for data files, 1
When a request to write data to one data file occurs and there is no record that is written sequentially in the initial state, another file that manages the key information of the record whose data was deleted from the data file is referred to, and the corresponding When a record of a record in which data in the data file has been deleted exists in the file, the key information of the record is read, and the record in which the data in the data file has been deleted is indexed from the read key information. , is configured to write to a record of the indexed data file.

[Industrial Application Field] The present invention relates to an unused record search method for a file storing data in an information processing device, and particularly to a method for searching without accessing a file storing data.

[Conventional technology] Conventionally, in order to add data to a file where data is written or deleted, it is necessary to perform processing to detect unused records where data has been deleted and become unused, which takes a lot of processing time. There was a problem that it took a while.

That is, as shown in FIG. 4, step 11 (
311) to 320 are required. First, the process
In S11, it is determined whether the write position (WP) of the data file is equal to the last record (EOF). If not, the process advances to S12, and if they are equal, the process advances to S14. S1
In No. 2, the WP has not reached EOF and is still in the stage before additional writing, so it is possible to write to the WP record, and the process ends when the writing is completed. In S14, the read position (RP) of the data file is set to the first record. Next, in S15, the RP record is read, and it is determined whether the RP record is in use (S16). If the record is not in use, the process advances to S17, and if the record is in use, the process advances to S18. In S17, data is written to the RP record. In 318, the RP is updated and the process advances to S19.
In step 9, when RP does not reach EOF, the process returns to S15, and when it does, writing is disabled (S20) and the process ends. In these processes, it takes time to repeat steps 315 to 319. A record here indicates a storage area.

[Problems to be Solved by the Invention] As mentioned above, in order to use unused records in a file with a large number of records and add data, it is necessary to add unused records (records that have become unused due to data deletion). ), it takes a lot of processing time. Therefore, shortening the processing time was an issue.

Therefore, an object of the present invention is to shorten the processing time when adding data to a data file, that is, the access time for unused records.

[Means to solve the problem]

In the first embodiment of the present invention, as illustrated in FIG. 1, in the data file unused record search method, when a request to write data to one data file occurs, data is written sequentially in the initial state. If the record does not exist (S1), refer to another file that manages the key information of the record whose data has been deleted from the data file (S2), and add the record whose data has been deleted from the data file to another file. If a record exists (S3), read the key information of the record, and
A method for storing a data file characterized by indexing a record from which data in the data file has been deleted from the retrieved key information (S5), and writing to the indexed record in the data file (S6). A usage record search method is provided.

In a second embodiment of the present invention, as illustrated in FIGS. 2 and 3, there is provided a method for searching for unused records in a data file, which method deletes data from data file 1 and the data file. A deleted record management file 2 is provided for managing key information of records that have been deleted, and when an empty record is generated due to deletion of data in the data file 1 and an attempt is made to write to the empty record, the deleted record management file 2 is referred to. However, there is provided an unused record search method for a data file in which the empty record is indexed and written based on the key information of the record from which data has been deleted.

[For production]

The operation of the present invention will be explained using FIGS. 2 and 3. In the figure, 1 is a data file that stores data, and 2 is a deleted record management file that adds deletion information when data is deleted from file 1 and manages unused records in file 1. As shown in FIG. 2, the process when data is deleted from file 1 will be explained. File 1 and File 2 are managed by an application program and file management 3. First, the data in file l is deleted using the arrow ■. Next, deletion information (file type and key information) is written to file 2 (arrow ■). Key information is data file 1
corresponds to the address of

Next, as shown in FIG. 3, the deletion information is read out in order from the beginning of the file 2 (arrow ■). Furthermore, an unused record in file 1 is directly searched using the key information of the read deletion information, and data is added (arrow ■). File management 3 deletes the deletion information at the beginning of file 2. In this way, instead of searching file 1 to find empty records, it is sufficient to search for deletion information in file 2, thereby making it possible to shorten the access time.

[Embodiment] FIG. 1 shows a flowchart of a process for searching for unused records in a data file as an embodiment of the present invention.

Data file 1 writing process is step 1 (Sl)
37. In Sl, it is determined whether WP (write position of file l) is at the last record position of file l. If it is not the final record position, the data file is in the initial stage of storing sequential data and not in the additional writing stage, so the process goes to 36. In S6, data is written to the WP position, writing is enabled (S7), and the process ends. If the final record position 1 has been reached in Sl, the process advances to step 52 because it is at the additional recording stage. In S2, the first data of file 2 (a file that manages key information of deleted records) is read, and the process advances to S3. In S3, it is determined whether or not there is data in file 2. If there is no data, data writing is disabled (S4) and the process ends. If there is data (YES in S3), an unused record is searched from the deletion information (S5). Next, the process advances to S6, and additional data is written to the data file at the address corresponding to the key information of the retrieved record. This data is processed as write-enabled (S7), and the process ends.

If you directly search for a data file, in the longest case, you will have to read all the files to make a decision, but in file 2, the information about deleted records is stored from the beginning position, so the key of the record deleted from file 2 is Searching for a data file from the address corresponding to the key information after reading the information will probably save time.

File 2 can also manage information on deleted records of data files other than File 1.

〔Effect of the invention〕

According to the present invention, it is possible to shorten the processing time when additionally writing data in a data file, that is, the time to access unused records.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the process of searching for unused records in a data file as an embodiment of the present invention, and FIGS. 2 and 3 are process diagrams for explaining the present invention. FIG. 4 is a flowchart of the processing process of the conventional method. In the figure, 1...data file, 2...deletion record management file, 3...file management, 4...application program.

Claims (1)

[Claims] 1. In an unused record search method for a data file, when a request to write data to one data file occurs and there is no record to be written sequentially in the initial state (S1), the data is Refers to another file that manages the key information of the record from which data has been deleted from the file (S2), and if the record of the record from which data in the data file has been deleted exists in the other file (S3), the record is The key information of the data file is read out, a record from which data of the data file has been deleted is indexed from the read key information (S5), and a record of the indexed data file is written (S6). Unused record search method for data files. 2. An unused record search method for a data file, which method includes a data file (1) and a deleted record management file (2) that manages key information of records from which data has been deleted from the data file. When an empty record is created by deleting data in the data file (1) and an attempt is made to write to the empty record, the deleted record management file (2) is referred to and the key information of the record from which the data was deleted is used. An unused record search method for data files that indexes and writes empty records.