JPH01140228A - Data storage retrieving system - Google Patents

Abstract

PURPOSE:To delete a necessary change place at the time of reorganization to a data file by making correspondence information between a record serial- number assigned to a data record and a storage address on the data file into address converting information. CONSTITUTION:A serial-number assigning means 1 adds 1 to the largest record serial-number in a converting information storage data 8 in a data file 7, assigns the record serial-number to the data record to be stored, a storage means 2 stores the data record whose assigned record serial-number is added into a storage area 9, a storage means 3 stores the correspondence information between the record serial-number and the storage address as the address converting information into a storage area 8, a storage means 4 stores an index record with a stored data value as a key value and with the record serial-number as pointer information into a storage area 6 in a file 5. The record serial-number is obtained from the index record corresponding to the key value by a retrieving means 10, converted into the storage address by a converting means 11 and the data record is removed from the storage area 9 by a reading means 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention stores a data record on a data file, stores an index record having a data value in the data record as a key value on the index file, The present invention relates to a data storage and retrieval method for reading data records according to pointer information obtained by retrieving index records using specified key values.

[Conventional technology]

Conventionally, in this type of data storage search method, the storage address of the data record on the data file itself is stored as pointer information in the pointer information section of the index record for the data record stored on the data file, and the storage address itself of the data record on the data file is stored as pointer information. The system searches for an index record with a key value equal to the specified key value, and reads the data record from the data file according to the storage address pointed to by the pointer information in the found index record. That is, as shown in FIG. 5, a data record DI having a data value di at address i on the data file, and a data record DJ having a data value dj at address j.
is a data record D with data value dk at address k.
When K is stored, address i is stored in the pointer information field of index record II with key value ki (=di), address j is stored in the pointer information field of index record IJ with key value kj (=dj), and key value kk
The address k is stored in the pointer information section of the index record IK having (=dk).

For example, when relocating the data record DJ by reorganizing or reconfiguring the data file, search the index record in the index file using 1dj as the key key, and search for the index record in the index file with the key value [kj( ``dj)J'' index record I
Address j of the pointer information section of J, data record D
Change it to point to the new storage address of J.

If there are other indexes pointing to the data record DJ, the pointer information sections in all index records are repeatedly changed.

[Problem that the invention seeks to solve]

The conventional method described above uses the data record storage address itself as pointer information pointing to the data record of the index record for the data record stored on the data file. If you change the storage location in the data file for all or part of the data records in the data file, the pointer information section of all index records pointing to the data records to be relocated will be changed as described above. need to be changed. Therefore, if multiple indexes exist for a single data file (which is often the case), pointers to more index records than the number of data records subject to reorganization, reorganization, etc. The disadvantage is that it is necessary to change the information section, and it is difficult to quickly reorganize, reconfigure, etc. the data files.

An object of the present invention is to provide a data storage and retrieval method that can reduce the number of changes required when reorganizing, reconfiguring, etc. a data file.

[Means for solving problems]

In order to achieve the above object, the present invention stores a data record on a data file, stores an index record having a data value in the data record as a key value on the index file, and stores the index record with a specified key. In a data storage and retrieval method in which a data record is read according to pointer information obtained by searching by value, a record sequence number assigning means for assigning a record sequence number to a data record stored in a data file; a data record storage means for adding a record serial number assigned to the data record to the data record and storing it in a data record storage area in a data file; a record serial number assigned to the data record by the record serial number assigning means; Address translation information storage means for storing correspondence information of the data record stored by the data record storage means with a storage address on the data file as address translation information in an address translation information storage area in the data file; and the data record. Generating an index record in which the data value in the data record stored by the storage means is used as a key value, and the record sequence number assigned to the data record by the record sequence numbering means is used as pointer information for pointing to the data record. and an index record storage means for storing in an index record storage area in the index file, searching the index record stored by the index record storage means using a specified key value,
an index search means for obtaining a record serial number from the print information of an index record corresponding to a specified key value; and a record serial number obtained by the index search means,
an address conversion means for converting a data record into a storage address on a data file using the address conversion information; and a data record read for reading a data record using the storage address on the data file of the data record converted by the address conversion means. and means.

[Effect]

When storing a data record in a data file, the data record to which the record sequence number assigned by the record sequence numbering means is added is stored in the data file, and an address indicating the correspondence between the record sequence number and the storage address is stored in the data file. The conversion information is stored in the address conversion information storage area, and an index record having the data value in the stored data record as a key value and the assigned record sequence number as pointer information is stored in the index file by the index record storage means. stored within.

When a search with a specified key value is instructed, the index search means searches for index records using the specified key value, and obtains the record sequence number indicated by the pointer information of the index record with the specified key value. The storage address of the target data record is determined by the address conversion means from this record serial number and the address conversion information, and the data record reading means reads the data record from the data file in accordance with this storage address.

Even if multiple index records exist for one data record, there is only one address conversion information, which is a pair of record serial number and storage address corresponding to that data record. When the storage position of a data record in a data file is changed due to processing such as reconfiguration, it is only necessary to change the address conversion information corresponding to the rearranged data record.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which a record serial number is assigned to a data record to be stored when a data record is stored in a data record storage area 9 in a data file 7. Means 1 and
A data record storage means 2 adds a record serial number assigned by the record serial number assigning means 1 to a data record and stores it in a data record storage area 9 in a data file 7; The address conversion information storage area in the data file 'f is set as address conversion information, which corresponds to the record serial number stored by the data record storage means 2 and the storage address in the data record storage area 9 in the data file 7 for the data record stored by the data record storage means 2. The key value is the data value in the data record stored by the address conversion information storage means 3 stored in the address conversion information storage means 8 and the data record storage means 2, and the record serial number assigned to the data record by the record serial number assignment means l is used as the key value. Index record storage means 4 that generates an index record as pointer information for pointing to a data record and stores it in an index record storage area 6 in the index file 5
, an index search means lO that searches the index record stored by the index record storage means 4 using a specified key value, and obtains a record serial number from the pointer information section of the index record having the specified key value; The record sequence number obtained in step 10 is stored in the data record storage area 9 of the data file 7 of the data record by the address conversion information storage means 3 using the address conversion information stored in the address conversion information storage area 8 of the data file 7. an address conversion means 11 for converting the data record into a storage address of , and a data record reading means 12 for reading the data record according to the storage address on the data record storage area 9 in the data file 7 of the data record converted by the address conversion means ll; Data record relocation for relocating data records when it is necessary to change the storage position of the data record in the data record storage area 9 of the data file 7 due to processing such as reorganization or reconfiguration for the data file 7 means 14 and data record relocation means 14
and address conversion information changing means 13 for changing the address conversion information for the record serial number assigned to the rearranged data record by the rearrangement to the storage address of the rearranged data record.

FIG. 2 is a diagram showing an example of the contents of the index record storage area 6 in the index file 5, the address translation information storage area 8 and the data record storage area 9 in the data file 7.

FIG. 3 shows the address conversion information storage area 8, data record storage area 9, and index file 5 after a new data record DK is stored in the data record storage area 9 of the data file 7 in the state shown in FIG. is a diagram showing an example of the contents of the index record storage area 6, and by storing the data record DK, an index record TK having a key value kk and a record serial number nk as pointer information is added to the index file 5, A state in which an address k is added to the address conversion information storage area 8 in correspondence with a record serial number nk is shown.

FIG. 4 shows the data record DJ stored in the data record storage area 9 in the data file 7 as shown in FIG.
indicates the state when is relocated from address j to address
This shows a state where address j corresponding to j has been updated to address X.

Next, with reference to an example in which the data record DK is stored in the data file 7 in the state shown in FIG. 2, the state shown in FIG. explain.

In the address conversion information storage area 8 in the state shown in FIG. 2, storage addresses i and j are lined up in the order of record serial numbers ni and nj, and the largest record serial number is record serial number nj. In the data record storage area 9, a data record DI and a data record DJ are stored at addresses i and j, respectively.
is stored in. In the index record storage area 6, there is an index record TI in which the data value di of the data record DI is set as the key value ki and the record serial number ni is stored in the pointer information field, and the data value dj of the data record DJ is set as the key value kj, and the pointer An index record IJ storing a record serial number nj is stored in the information section.

When a new data record DK is to be stored in the data file 7 in the state shown in FIG. The maximum record sequence number nj is known from the address conversion information storage area 8 in the address conversion information storage area 8, and by adding 1 to the record sequence number nj, the record sequence number nk is assigned to the data record DK to be stored.

Next, data record D is stored by data record storage means 2.
The record serial number nk assigned by the record serial number assigning means 1 is added as the record serial number in K, and is stored in the data record storage area 9 in the data file 7 as shown in FIG. The storage address on the data file 7 at this time is k.

Next, the address conversion information storage means 3 stores the data record D.
The correspondence information between the record serial number nk for K and the storage address on the data file 7 is stored as address conversion information in the address conversion information storage area 8 in the data file 7 as shown in FIG. At this time, the record sequence number k becomes the maximum record sequence number.

Next, the index record storage means 4 uses the data value dk in the stored data record DK as a key (directly kk), and uses the record serial number nk assigned to the data record DK by the record serial number assigning means 1 as pointer information. The index record !K is stored in the index record storage area 6 in the index file 5 as shown in FIG.

This completes the storage process of the new data record DK.

Next, the search processing in this embodiment will be described using, for example, a case where the key value rk jJ is given as a search key to the data file 7 and index file 5 in the state shown in FIG. 3.

The index search means 10 searches the index records stored in the index record storage area 6 in the index file 5 using the specified key value rk jJ, and searches for the index record corresponding to the key value rk jJ. IJ is obtained, and a record serial number nj is obtained from the pointer information section of index record IJ.

Next, the address conversion means 11 performs index search means l.
The record serial number nj obtained by O is converted into a storage address j using the contents of the address conversion information storage area 8 in the data file 7.

Then, the data record reading means 12 reads the data record DJ from the data record storage area 9 in the data file 7 using the storage address J converted by the address conversion means 11.

Next, referring to an example in which the data record DJ in FIG. 3 is relocated due to reorganization, reconfiguration, etc., the state as shown in FIG. The process will be explained.

The data record relocation means 14 relocates the data record DJ stored at address j of the data record storage area 9 in the data file 7 to a new storage address rxJ as shown in FIG. 4, and changes the address conversion information. Therefore, the address translation information changing means 13 is activated.

The address conversion information changing means 13 is a data record FDJ.
The storage address corresponding to the record sequence number nj in the address conversion information storage area 8 in the data file 7 is changed from address j to address X.

At this time, there is no need to change the record serial number nj in the pointer information section in the index record IJ.

〔Effect of the invention〕

As explained above, the present invention assigns record serial numbers in the order in which data records are stored, without directly using the storage addresses of data records stored on a data file as pointer information, and then combines the record serial numbers and storage addresses. By having the corresponding information as address conversion information and storing the record serial number in the pointer information section of the index record as a pointer information axis for pointing from the index record to the data record, processing such as reorganization and reconfiguration, Even if it becomes necessary to change the storage location in the data file for all or part of the data records in the data file, all you need to do is change the address conversion information corresponding to the data record to be relocated, and the index There is no need to change the pointer information part of the index record in the file. Therefore, in a file system where multiple indexes exist for one data file, reorganization is possible.

This is particularly effective when data records are rearranged within a data file due to reconfiguration or the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS.
The figure is an explanatory diagram of the operation of the embodiment of the present invention, and FIG. 5 is an explanatory diagram of the conventional system. In the figure, ■...Record serial numbering means 2...Data record storage means 3...Address conversion information storage means 4...Index record storage means 5...Index file 6...Index record storage Area 7...Data file 8...Address conversion information storage area 9...Data record storage area IO...Index search means 11...Address conversion means 12...Data record reading means 13... Address conversion information changing means 14...data record relocation means

Claims (1)

[Claims] A data record is stored on a data file, an index record having a data value in the data record as a key value is stored on the index file, and the index record is searched using a specified key value. In a data storage and retrieval method in which data records are read according to obtained pointer information, a record serial number assigning means assigns a record serial number to be assigned to a data record stored in a data file; data record storage means for adding a record serial number assigned to the data record to the data record and storing it in a data record storage area in a data file; and a record serial number assigned to the data record by the record serial number assigning means and the data record storage means. address conversion information storage means for storing, as address conversion information, correspondence information between the data record stored in the data file and the storage address on the data file in an address conversion information storage area in the data file; generates an index record that uses the data value in the data record as a key value and uses the record sequence number assigned to the data record by the record sequence numbering means as pointer information for pointing to the data record, and an index record storage means for storing in an index record storage area; searching an index record stored by the index record storage means using a specified key value;
an index search means for obtaining a record sequence number from pointer information of an index record corresponding to a specified key value; and a record sequence number obtained by the index search means;
an address conversion means for converting a data record into a storage address on a data file using the address conversion information; and a data record read for reading a data record using the storage address on the data file of the data record converted by the address conversion means. A data storage and retrieval method characterized by comprising means.