JPH0232468A - Character string data retrieving system - Google Patents

Abstract

PURPOSE:To reduce the number of times of the comparison of character string data, and to shorten a retrieving time by storing a random number value together with the character string data, generating the random number value at the time of retrieve, and first comparing them. CONSTITUTION:When a user inputs a character string data storing request through an input means 1, a character string data memory means 2 designates the inputted character string data, accesses a random number generating means 3, and generates the random number value. The means 2 stores them into a data base 5 as the second character data and the random number value. When the user inputs the character string data retrieving request, in the same way as the storing request, the first character string data and the random number value are generated by a character string data retrieving means 4 and the means 3. Next the first and second random number values are compared, only at the time of correspondence, by comparing the character string data character by character, the number of times of the comparison necessary for the retrieve can be reduced, and the time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a character string data retrieval method, and in particular, the present invention relates to a character string data retrieval method, and in particular to a method for searching character string data ( The first character string data (hereinafter referred to as the first character string data) is compared with the character string data stored in the database (hereinafter referred to as the second character string data), and the second character string data that completely matches is stored in the database. This invention relates to a string data search method for extracting character string data.

[Conventional technology]

Conventionally, in this type of string data search method, second string data is stored in the database, and in response to a string data search request from a user to the database, the first string data and the second string data are stored in the database. The first character string data is compared character by character, starting with r, and when they no longer match, it is determined that the first character string data and the second character string data do not completely match, and all characters are Only when they match, it is determined that the first character string data and the second character string data completely match, and the second character string data is extracted from the database.

[Problem to be solved by the invention]

In the conventional character string data search method described above, the first character string data and the second character string data are compared character by character from the beginning, so as the size of the character string data to be compared increases The disadvantage is that it takes a lot of time to search because the number of searches increases.

In particular, when much of the second character string data starts with the same value, the number of comparisons described above becomes large.

In view of the above-mentioned points, an object of the present invention is to store character string data specified by the user in a database as well as random numbers generated based on this character string data, and to This method generates random values based on the string data obtained and compares the random values before comparing the string data to avoid comparing string data that may not be an exact match. To provide a character string data search method capable of reducing the number of comparisons and search time.

[Means to solve the problem]

The string data search method of the present invention includes a random number generation means that calculates a random value of an integer attribute that can be regenerated based on the value of string data, and a response to a request from a user to store string data in a database. a character string data storage means for storing character string data specified by a user in a database together with a random number value calculated by the random number generating means; A random value is generated after comparing the calculated random value using the random number generation means based on the value of the specified character string data and the random value stored in the database together with the character string data. The apparatus includes a character string data search means that compares the character string data specified by the user with the character string data stored in the database only if they match.

[Effect]

In the string data search method of the present invention, the random number generation means calculates a random value of an integer attribute that can be regenerated based on the value of the string data, and the string data storage means inputs the string from the user into the database. String data specified by the user in response to a data storage request is stored in the database together with a random number value calculated by the random number generation means, and the string data search means responds to the string data search request from the user to the database. A random number is calculated using a random number generator based on the value of the string data specified by the user, and the calculated random number is compared with the random number stored in the database along with the string data. After that, the character string data specified by the user is compared with the character string data stored in the database only if the random numbers match.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a string data search method according to an embodiment of the present invention. It is composed of a random number generation means 3, a character string data search means 4, a database 5, and an output means 6.

In the human power means 1, a user requests storage of character string data.

This is a means for inputting a character string data search request and character string data.

The output means 6 is means for outputting second character string data as a result of character string data search.

Database 5 is similar to that found in typical database management systems.

Referring to FIG. 2, the processing in the character string data storage means 2 consists of a character string data input step 21, a random number generation step 22, and a character string data storage step 23.

Referring to FIG. 3, the processing in the random number generation means 3 is as follows:
Variable n (n is an integer) initialization step 31, character string data first character variable c (c is an integer) cent step 32, variable n variable C addition step 33, variable C character string data last character determination step 34 , variable C next character cent step 35.

Referring to FIG. 4, the processing in the character string data search means 4 includes a first character string data input step 41;
Random value generation step 42, second character string data reading step 43, second character string data presence/absence determination step 44, second random value reading step 45, random value matching determination step 46, character It consists of a string data match determination step 47 and a second character string data output step 48.

Next, the operation of the character string data search method of this embodiment configured as described above will be explained.

The character string data storage means 2, which is activated by the input of a character string data storage request from the user through the input means 1, first inputs character string data to be stored in the database 5 through the input means 1. is received from the user (step 21).Next, the character string data storage means 2 specifies the input character string data and calls the random number generation means 3 (
Step 22).

The random number generation means 3 called from the character string data storage means 2 generates a variable n for storing random numbers in the database 5.
is initialized to O (step 31), and the first character of the character string data specified by the character string data storage means 2 is placed in variable C (step 32).Next, the value of the character code of variable C is initialized. The converted numerical value is added to the current value of the variable n (step 33).Next, the random number generation means 3
It is determined whether the character placed in the variable C is the last character in the character string data (step 34), and if it is the last character, the process is terminated. If it is not the character after Il, the random number generation means 3 resets the variable C to the next character in the character string data (step 35), returns to step 33, repeats the process, and generates a variable value. .

As an actual random number generation method, a random number generation method used in known techniques such as hashing can be applied. However, unlike the hashing technique, there is no need to limit the numerical range according to the size of the hash table.

Once the random number value is generated, the character string data storage means 2 stores the character string data input by the user and the random number generation means 3.
The generated random numbers are stored in the database 5 as second character string data and second random numbers, respectively (step 23).

In this way, the second random value is stored in the database 5 together with the second character string data.

On the other hand, when activated by inputting a character string data search request from the user via the input means 1, the character string data search means 4 first searches for first character string data via the input means 1. Receive input from the user (Step 41)
), the receiver designates the obtained first character string data and calls the random number generation means 3 (step 42).

The random number generation means 3 called by the character string data search means 4 generates a first random number value in the same manner as when called from the character string data search means 4.

Once the first random number value has been generated by the random number generation means 3, the character string data search means 4 reads the second character string data stored in the database 5 (step 43).
), it is determined whether or not the second character string data exists in the database 5 (step 44). If the second character string data does not exist in the database 5, the character string data search means 4 executes the process. When the second random number value exists, the second random value stored together with the second character string data is read from the database 5 (step 45). Next, the character string data search means 4 compares the first random value and the second random value (step 46), and if they do not match, returns to step 43 and reads the next second character string data, Manipulate the process. When the first random number value and the second random number value match, the character string data search means 4 compares the first character string data and the second character string data in order from the first character. (Step 47), if the first character string data and the second character string data match, the character string data search means 4 outputs the second character string data to the output means 6, and then (step 47) 48) Return to step 43 and repeat the process. If the first character string data and the second character string data do not match, the character string data search means 4 skips step 48 and repeats the process in step 43. Return to and repeat the process.

〔Effect of the invention〕

As explained above, the present invention stores random values together with character string data in a database, generates random values when searching for character string data, and compares the random values before comparing character string data. , it is possible to exclude from comparison most of the string data for which there is no possibility of an exact match without actually comparing the string data character by character, which reduces the total number of comparisons required for string data searches. This has the effect of shortening the search time. In particular, the above effect is remarkable when much of the character string data stored in the database starts with the same value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a character string data search method according to an embodiment of the present invention, FIG. 2 is a flowchart showing the processing in the character string data storage means in FIG. 1, and FIG. 3 is the same as that shown in FIG. 1. 4 is a flowchart showing the processing in the random number generation means in FIG. 1. FIG. 4 is a flowchart showing the processing in the character string data search means in FIG. In the figure, 1...Input means, 2...Character string data storage means, 3...Random number generation means, 4...Character string data search means, 5...Database, 6...Output means It is.

Claims (1)

[Claims] Random number generation means for calculating a random value of an integer attribute that can be regenerated based on the value of character string data; a character string data storage means for storing the generated character string data in a database together with the random number value calculated by the random number generation means; A random number that matches the random number after comparing the calculated random number using the random number generation means based on the value of the column data and the random number stored in the database together with the character string data. 1. A character string data search method comprising a character string data search means for comparing character string data specified by a user with character string data stored in a database.