JPH0869476A - Retrieval system - Google Patents

Abstract

PURPOSE: To specify the object data including an optional character string by the logical operation of an index bit map only and to improve the retrieval processing efficiency for free words of a summary, etc. CONSTITUTION: A retrieval system includes a retrieval data file 1 which stores the retrieval object data consisting of many characters, a bit map file 3 which stores an index bit map 4 consisting of the bit strings that can identify the retrieval object data using the characters as the index keys and also identify the character positions, a bit map production processing part 2 which sets the corresponding bit of the map 4 at '1' when the retrieval object data are stored in the file 1, and a bit map retrieval processing part 5 which retrieves the map 4 by each character of the retrieval character string received from an input device 6 to input the corresponding bit string, shifts left the bit strings following the 2nd character by a bit number equivalent to a position difference to calculate an AND of each bit string, and specifies a data number including a bit having its AND equal to '1' to output this number to a display device 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a search system, and more particularly to a search system for extracting search target data containing an arbitrary character string from a database in which a large amount of search target data consisting of many characters are stored.

[0002]

2. Description of the Related Art A free word for selecting and extracting search target data containing a specified arbitrary search character string from a search data file in which search target data consisting of a large number of characters such as abstract sentences and commentary sentences are accumulated. The most basic method of searching is to enter the search target data in the search data file in sequence and match the search character string with all the search target data to find the search target data containing the corresponding search character string. Is a method of identifying. However, since this method takes too much time for searching, a method of limiting the number of search target data to be matched with the search character string by preliminary search processing is proposed in Japanese Patent Laid-Open No. 62-217728.

This system has a character index having a bit string for specifying the data number of the search target data in which the character is used for each character, and each character in the search character string specified as the search condition Then, the bit string is obtained from this character index, the logical product operation is performed between the bit strings, and the search target data including all the characters of the search character string is preliminarily searched from the result. The search target data selected by the above preliminary search includes all characters in the search character string, but the character array is unknown and may not necessarily be arranged in the order of the search character string. It is necessary to read the entire text of the data and collate it with the search character string to determine the target search target data. Therefore, although the number of search target data can be limited, it is still essential to match the search target data with the search character string.

A proposal that further improves the above-mentioned method and limits the number of search target data to be collated with a search character string to a number close to only a confirmation purpose is disclosed in Japanese Patent Laid-Open No. 3-125263. This proposal uses, in addition to the above-mentioned character index, a compound word index having a two-character compound word having the same structure as the character index as an index key. That is, a search character string is decomposed into two-word collocations at the time of search, a bit string is obtained from the collocation index using this collocation as a key, and the search target data including the search character string is further limited by logical operation of the bit string. is there.

[0005]

However, the conventional search system that also uses the above-mentioned collocation index requires a character index in addition to the collocation index in order to search for a single character, which increases the scale of the index. Not only that, but finally, there remains a problem that it is necessary to collate the search target data with the search character string.

First, since the number of index items in a compound index is the square of the number of characters in consideration of compound words of all characters, the larger the number of characters that can be used, the larger the size of the compound index (the number of index items is the same as the number of characters). ) Will be larger than the scale of, and the index search will also take time. Furthermore, even if the search string is decomposed into two-word collocations and the existence of all collocations is confirmed, the position and order of the collocations are not specified, so the final check is made by matching the search target data with the search character string. is necessary. For example, if "search for information" is the search string,
4 of "information""report""inspection""search" which decomposed this
This is because even if all the collocations are confirmed, it cannot be guaranteed that the character string “search for information” exists. That is, when one search target data includes two character strings “accumulation of information” and “search of index”, the search target data has the above-mentioned quadruple word and “search for information”. Since it is extracted even if the character string is not included, confirmation is required.

The object of the present invention is to solve the above-mentioned problems, to eliminate the need for collating the retrieval target data with the retrieval character string, and to retrieve the retrieval object matching the retrieval condition only by the retrieval of the index bitmap and the logical operation. It is to provide a search system that can reliably identify data.

[0008]

According to a first aspect of the present invention, there is provided a search system in which a search data file containing a plurality of search target data composed of a large number of characters contains a specified arbitrary search character string. In the search system of the free word method for extracting, the bit string configured to identify the search target data in which the character (A) is used as an index key and the character position in the search target data corresponds to the total number of characters. The arranged index bitmap and (B) all characters used for the search target data when storing the search target data in the search data file are logically “1” in the corresponding bit of the index bitmap.
(C) The index bitmap is sequentially searched with each character specified in the search character string as a key, and the corresponding bit string is input to correspond to the second and subsequent characters. Each bit string is left-shifted within the range of each search target data by the number of bits equal to the position difference from the first character of the search character string, and the logical product is calculated and the search target data including the bit of logical "1" is searched. And a bitmap search processing unit that specifies search target data that matches the conditions.

A search system according to a second aspect is the search system according to the first aspect, wherein the index bitmap is created for each block obtained by dividing a search target data group into a plurality of blocks, and for each character, in each block. A hierarchical structure is formed with a block index bitmap in which a bit string having a number of bits equal to the number of blocks for identifying whether or not the character is used is formed, and the bitmap creation processing unit sets the search target data to the search data file. Has a function of registering necessary information also in the block index bitmap when storing it in, and the bitmap search processing unit searches the block index bitmap at the time of search and determines a processing target from a logical product of corresponding bit strings. It is characterized in that a block is determined and the index bitmap of the block is processed.

[0010]

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

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

As shown in FIG. 1, the search system of this embodiment uses a search data file 1 in which a plurality of search target data consisting of a large number of characters are stored, and a character used for the search target data as an index key. When storing the search target data in which the character is used and the bitmap file 3 storing the index bitmap 4 composed of a bit string configured to identify the character position and the search target data in the search data file 1. Bitmap creation processing unit 2 that sets the corresponding bit of index bitmap 4 to "1"
Then, the index bit map 4 is searched with each character of the search character string specified from the input device 6, the corresponding bit string is input, and the bit strings subsequent to the second character are shifted to the left by the number of bits corresponding to the positional difference. The bit map search processing unit 5 is configured to obtain a logical product of bit strings, specify a data number of search target data including a bit whose output is “1” as search target data, and output the data number to the display device 7.

The search system of the present embodiment is a free word system search system that selects and extracts search target data containing a specified arbitrary search character string from search target data in the text format such as abstract sentences and commentary sentences. In addition, although the search data file 1 stores other information other than the search target data, FIG. 1 shows the data number for identifying each data unit and the free word search target. Only the data to be searched are shown. Furthermore, in order to simplify the explanation and make it easier to understand, the used characters are shown in uppercase letters, and only a few letters at the beginning of the sentence are shown.

The index bitmap 4 uses the character used for the search target data as an index key so that the data number of the search target data in which the character is used and the character position in each search target data can be identified. It is composed of a bit string in which bits for the maximum number of characters allowed in one data are arranged in the order of data numbers. In the example of FIG. 1, the character “A” is the first character of the data number # 1 and the first character of the data number # 2, and the character “B” is the second character of the data number # 1 and the second character of the data number # 2. The character “C” is the third character of the data number # 1, the third character of the data number # 2 and the first character of the data number # 3, and the character “G” is the data number #.
It indicates that it is used in the 5th character of 3. The index bitmap 4 is created by the bitmap creation processing unit 2 when the search target data is stored in the search data file 1, and “1” is registered in the bit of the corresponding character position of the corresponding data number of the index bitmap 4. It When deleting data, all bits of the corresponding data number in the index bitmap 4 are initialized to "0". In addition, when additional data numbers are added, the required number of bits (the number of additional data × the maximum number of characters) is added to each bit string of the index bitmap 4.

The bit map search processing unit 5 includes an input device 6
Index bitmap 4 by the search character string specified from
Is searched for and the logical operation processing is performed, the data number of the search target data including the search character string is specified and output to the display device 7. Further, if there is a request, it is possible to read and display the full text of the search target data or other information from the search data file 1 by the data number. Hereinafter, the input device 6
The process of the bitmap search processing unit 7 will be specifically described by taking as an example the case where "CD" is input as the search character string from.

When the search character string "CD" is input and search start is instructed, the bitmap search processing unit 5 firstly
All the bit strings of the index character “C” are input from the index bitmap 4. Next, all the bit strings of the index character “D” are input, and as shown in FIG. 2, each bit string of the data number is shifted to the left by one bit. Finally, the bitmap search processing unit 7 determines that the input index character “C” has been input.
And the shift result of the bit string of the index character “D” are obtained. The progress of this logical operation is shown in FIG. From the bit string of the operation result of FIG. 3, a data number including a bit of logical “1” is specified in the bit string for each data number, and the data number is displayed on the display device 7. FIG.
In this case, since the bit string of data numbers # 1 and # 3 has the bit “1”, the search target data of data numbers # 1 and # 3 includes the character string “CD”. Since "1" does not exist in the bit string of number # 2, it indicates that the character string "CD" is not included in the search target data of data number # 2.

When the search character string has three or more characters, the bit string of the third character is left-shifted by 2 bits, and the bit string of the fourth character is left-shifted by 3 bits.
By shifting the number of bits (character position -1) corresponding to the character position in the search character string to the left and performing the logical product operation of each bit string, it is possible to specify the data number including the search character string in the same manner. it can. According to this method, it is possible to detect not only the existence of the corresponding character but also the order of arrangement of the character, only by searching the index bitmap with the character as the index key. The target search target data can be surely specified without performing the search.

In the above description of the embodiments, all bit strings corresponding to index characters are read and logical operations are performed, but as the number of search target data increases,
When all bit strings are input, the amount of bit shift and logical operation processing becomes enormous, so by dividing the index bitmap into block units and layering them, blocks that may not contain the search character string are It is considered effective to exclude it from the processing target by preprocessing. That is, the index bitmap is divided into n blocks such as block # 1 from data number # 1 to data number # 10, block # 2 from data number # 11 to data number # 20, and so on. However, a hierarchical structure is formed with a block index bitmap formed of an n-bit bit string for identifying whether or not the character is used in the block. In the case of the search, first, the block index bitmap is searched, the bit string is input, the logical product is simply obtained, and only the block corresponding to the bit of the logical value “1” is set as the subsequent processing target. With the above pre-processing, blocks that do not include all the characters in the search character string can be excluded from the processing target. When the above-mentioned block formation is performed, it is effective to collect information of the same field to form a block. Note that when registering the search target data in the search data file, it is also registered in the block index bitmap along with the index bitmap, but if it is already used by another data number of the same block, do not change it. Good. When deleting data, all bits of the corresponding data number of the index bitmap are initialized to "0", but the block index bitmap will process by checking other data numbers in the block.

[0019]

As described above, the search system of the present invention is provided with an index bit map capable of identifying the data number and the character position of the search target data in which the character is used to search from the index bit map. The search target data that meets the search condition can be specified only by shifting the bit string and the logical operation, and direct matching between the search target data and the search character string is not required at all, thus improving the processing efficiency of the search system. There is an effect that can be greatly improved. When the number of search target data is large, the index bit map is divided into blocks and hierarchized to prevent the length of the bit string of the logical operation target from increasing.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a bit string shift operation in a bitmap search processing unit.

FIG. 3 is an explanatory diagram showing a concept of a logical product operation in a bitmap search processing unit.

[Explanation of symbols]

 1 Search Data File 2 Bitmap Creation Processing Section 3 Bitmap File 4 Index Bitmap 5 Bitmap Search Processing Section 6 Input Device 7 Display Device

Claims (2)

[Claims] 1. A free word system search system for extracting search target data containing a specified arbitrary search character string from a search data file in which a plurality of search target data composed of a large number of characters are stored, (A) An index bitmap in which a search target data in which the character is used as an index key and the character position in the search target data are identified by a bit string arranged for all the characters, and (B) A bitmap creation processing unit that registers all the characters used in the search target data when storing the search target data in the search data file as a logical "1" in the corresponding bit of the index bitmap;
(C) The index bitmap is sequentially searched by using each character specified in the search character string as a key, the corresponding bit string is input, and the bit strings corresponding to the second and subsequent characters are respectively set as the first character of the search character string. After performing a left shift within the range of each search target data by the number of bits equal to the position difference, the logical product is obtained, and the search target data including the bit of logical “1” is specified as the search target data that matches the search condition. A search system comprising a bitmap search processing unit. 2. The block for creating the index bitmap for each block obtained by dividing a search target data group into a plurality of blocks, and identifying for each character whether or not the character is used in each block. Form a hierarchical structure with a block index bitmap in which bit strings having the same number of bits are arranged, and the bitmap creation processing unit stores necessary information in the block index bitmap when storing search target data in a search data file. The bitmap search processing unit has a function of registering, searches the block index bitmap at the time of search, determines a block to be processed from a logical product of corresponding bit strings, and processes the index bitmap of the block. The search system according to claim 1, wherein