JPH0243677A - Index control system - Google Patents

Abstract

PURPOSE:To shorten a retrieving time and to improve processing efficiency by providing an index updating means to execute the updating processing of the retrieve corresponding to a key value extracted with a key value extracting means and a retrieve processing means to execute retrieve-processing with the use of the partial key of a corresponding item. CONSTITUTION:A key extracting means 10 is accessed at every index item at the time of the addition, alteration and deletion of a record, a value consisting of the all digits of the index item and a value starting from the arbitrary position of the index item are extracted as a key value list 1, and delivered to an index updating means 20. The index updating means 20 executes the updating processing of the index corresponding to the key value extracted by the key value extracting means 10, when a retrieve processing means 30 receives a retrieve element using an index file 2 having a character position from the top of the value, the number of the digits and item of the retrieving key in an index entry, it decides the type of the retrieving request, and executes a distribution retrieving processing for the partial key retrieving processing. Thus, the retrieving time can be shortened, and the processing efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an index management system that performs a search using a search key value that appears at any position in a specified item.

〔overview〕

In an index management method for an index created using all digits of the search target item, the present invention creates a dedicated index that includes the search target key value, and extracts or updates the part necessary for actual operation. , high-speed access using indexes even with small storage capacity,
This reduces the number of execution steps, shortens search time, and improves processing efficiency.

[Conventional technology]

One of the conventional methods (conventional method 1) uses a normal index in order to perform high-speed search processing using a key value starting from an arbitrary position in a specified item. The expression of a key value starting from an arbitrary position within an item is categorized into a prefix match, a middle match, and a suffix match for the corresponding item, and when evaluating the prefix match condition, the index of the corresponding item is used to minimize access. You can position the desired record using . However, in the case of a search request with middle or suffix matching conditions, the entire index for the corresponding item must be searched to determine whether or not it is the target record.

In addition, the other conventional method (conventional method 2) is intended to enable high-speed access using indexes even when specifying conditions such as middle match and suffix match, and in addition to indexing by item, it is also possible to perform indexing by division of items. A method of creating an index is generally adopted.

FIG. 6(a) shows an index access path that occurs in the evaluation of the middle matching condition or the trailing matching condition in the conventional method 1. In order to process a search request in which a middle match condition or a backward match condition is specified for an item with an index, access starts from the topmost node of the corresponding index.
Accesses sequentially up to the lowest node, compares the key value stored in the lowest node with the specified partial condition value, and stores the records in the lowest node while determining which records satisfy the specified partial matching condition. The determination is repeated until the last key value is reached.

FIG. 6(b) shows the solution in conventional method 2. For items f1, f2, and f3, in addition to ■1, ■2, and ■3, which are indexes representing the entire key of each item, Ill, which uses 5 to 8 digits of fl as a partial key index, 112 using the 9th to 11th digits of fl, I21 using the 7th to 13th digits of f2, and I31 using the 3rd to 6th digits of f3 are defined.

[Problem that the invention seeks to solve]

In conventional method 1, when performing a search with conditions applied only to the middle or rear part of a specific item, the condition determination cannot be completed unless all the lowest nodes of the index created for the item are accessed. , there is a problem that the search takes too much time when there are many target records.

In addition, in conventional method 2, it is necessary to generate indexes for the number of expected partial key search request patterns, which increases the secondary storage space for storing the indexes, and also to synchronize with updates of record contents. The problem is that the number of index update processes increases, resulting in a decrease in processing efficiency.

The present invention solves these problems, and aims to provide a method that can shorten search time and improve processing efficiency.

[Means for solving problems]

The present invention provides an index management system that includes means for creating an index using all digits of a search target item and means for creating an index for a search key value starting from an arbitrary position within the item. An index file containing the value of the above search key, the number of digits, and the character position from the beginning of the item is set up, and it is called when adding, changing, or deleting a record, and it is a key value extracting means for extracting a value starting from a position as a key value list; an index updating means for updating an index corresponding to the key value extracted by the key value extracting means; The present invention is characterized by comprising a search processing means for performing search processing.

[Effect]

The key extraction means is called for each index item when a record is added, changed, or deleted, and extracts the value consisting of all digits of the index item and the value starting from any position of this index item as a key value list, and the index update means give it to The index update means updates the index corresponding to the key value extracted by the key value extraction means, and the search processing means includes the value of the search key, the number of digits, and the character position from the beginning of the item in the index entry. When a search request is received using an index file with
The type of search request is determined, and the search process is performed for partial key search processing.

As a result, it is possible to achieve high-speed access using the index even in search requests using partial key values, and to construct an index consisting only of the parts necessary for actual operation.
It is possible to reduce the cost of storing indexes.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an index management system according to an embodiment of the present invention.

The embodiment of the present invention includes a key value list 1, an index file 2 which has the search key value, number of digits, and character position from the beginning of the search target item in the index entry, and is called when adding, changing, or deleting a record. The key value extraction means 10 extracts the value consisting of all digits of the index item and the value starting from an arbitrary position of the search target item as a key value list 1 and passes it to the index update process. It includes an index update means 20 that performs an index update process corresponding to the extracted key value, and a search processing means 30 that performs a search process using a partial key of the corresponding item.

The operation of the embodiment of the present invention configured as described above will be explained.

FIG. 2 is a flowchart showing the process flow of the key value extraction means 10. The key value extracting means 10 is called for each index item in the process of adding, changing, or deleting a record defined as having an index, and extracts a key value to be reflected in the index file 2.

This key value extraction means 10 registers, changes, and
Called with the update target key value as a parameter during deletion processing. As the key value to be reflected in the index file from the currently input update target key value, all digits of the manually entered key value,
Decomposes into values from the second digit to the last digit, from the third digit to the last digit, and outputs only the last digit to key value list 1 (
Steps 301-304). At this time, the starting digit position, number of effective digits, and record address are added to the extracted key value.

In the example of key value decomposition shown in FIG.
The key value “ABCDE” is “ABCDE”, BC
Decomposed into DE″″′CDE″, DE” and “E”,
5.4.3.2.1 as the number of effective digits, O, 1, 2.3.4 as the start position information, and record address 10 are added to each key value list 1 and output to the key value list 1.

FIG. 3 is a flowchart showing the processing contents of the index updating means 20. The index update means 20 sorts the key values output to the key value list 1 in ascending order (step 401), and updates the index file 2 according to the addition and deletion instructions attached to each key value unit (step 402). .

FIG. 4 is a flowchart showing the processing flow of the search processing means 30. When the search processing means 30 receives a search request using the index file 2, it determines the type of the search request (step 501) and performs three types of partial key search processing: forward match, middle match, and backward match. Allocate to. The operation for each search request type will be explained below.

(1) The key value of the prefix match search target and the start position = 0 in the item indicating a prefix match request are set as conditions (step 502), and the search processing step is called.

(2) A search using a specified part of an item specified as a middle match is executed as a key.
It is determined whether the search request has a fixed starting position or an arbitrary starting position (step 503). For a search with a fixed starting position, the starting position within the item and the search target key value are given (step 503).
Step 505), calls a search process for the target record.

In addition, when searching for a key value that appears in any part of a specified item, an instruction is given to remove the starting position within the item from the limiting conditions and to search for the target record using only the specified key value (step 506). ).

(3) Suffix match For the suffix match request, a search request for the target record is issued by giving the search target key and its number of digits (step 504).

〔Effect of the invention〕

As explained above, according to the present invention, by creating a dedicated index that includes search target key values, it is possible to achieve high-speed access using the index even in search requests using partial key values, and Since an index can be constructed from only the necessary parts, it is possible to reduce the cost of storing the index.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a flowchart showing the processing flow of the key value extracting means according to the embodiment of the present invention. FIG. 3 is a flowchart showing the processing flow of the index updating means according to the embodiment of the present invention. FIG. 4 is a diagram explaining the operation of the search processing means according to the embodiment of the present invention. FIG. 5 is a diagram showing an example of key value decomposition by the key value extracting means according to the embodiment of the present invention. FIG. 6 is a diagram showing examples of conventional methods 1 and 2. 1... Key value list, 2... Index file, 10.
. . . Key value extraction means, 20 . . . Index updating means, 30.
...Search processing means.

Claims (1)

[Claims] 1. An index management method including means for creating an index using all digits of a search target item and means for creating an index for a search key value starting from an arbitrary position within the item, An index file (2) is created in the index entry that contains the value of the above search key, the number of digits, and the character position from the beginning of the item, and is called when adding, changing, or deleting a record, and the value consisting of all digits of the index item is created. and a key value extraction means (10) for extracting a value starting from an arbitrary position of this index item as a key value list (1), and an index update process corresponding to the key value extracted by this key value extraction means. An index management method characterized by comprising: an index updating means (20) for performing the following: and a search processing means (30) for performing a search processing using a partial key of a corresponding item.