Data processing system, data retrieval system, data processing method and data retrieval method5799299Abstract A data processing system, a data retrieval system, a data processing method, and a data retrieval method requiring less time to update data to be used in retrieval. The dictionary data generator generates dictionary data from a code string on which data retrieval is to be performed using a key string. The dictionary tree generator generates a dictionary tree based on the dictionary data. The text data generator generates text data based on the code string. The text tree generator generates a text tree based on the text data. The retrieving unit retrieves a trailing string whose leading string contains part of or the whole key string, based on the dictionary tree 4 and the text tree. The changing unit changes the code string, and the updating unit updates the dictionary data, dictionary tree, text data, and text tree of the code string associated with the change, based on the contents of the change. Claims What is claimed is: Description BACKGROUND OF THE INVENTION
›TABLE 1!
______________________________________
Position
Code value
______________________________________
1 0
2 0
3 0
4 N
5 N
6 0
7 0
8 0
9 0
10 1
11 1
12 1
13 1
14 1
15 1
16 0
______________________________________
In this example, 0 is stored in the interval ›1 . . . 3!, N in the interval ›4 . . . 5!, 0 in the interval ›6 . . . 9!, 1 in the interval ›10 . . . 15!, and 0 in the interval ›16 . . . 16!. In this example, it is thought that a code string is divided into a sequence of code strings of the same value, that is, into intervals. To process this data on a computer, the straightforward method is to store code values sequentially at consecutive addresses in storage (first method). FIG. 53 shows how the code string in Table 1 is represented in the first method. In the first method, the position of each code value is proportional to the difference between the address of storage at which the code value is stored and the start address of storage where the code string is stored. This makes it possible to identify the address of a particular code value by performing usual calculation (add, subtract, multiply, and divide). That is, if the start address of storage where the code string is stored is A, then the address where the code value of a position is stored is calculated as follows: ›Formula 1! Address=Position+A-1 However, this method has the following problems: (1) Data occupies as many locations as there are code values, degrading the memory efficiency. In particular, when there are many codes of the same value, the memory is wasted. (2) Because data is stored by each code, it takes long time to determine a range of the consecutive codes of the same value. That is, to identify a range of consecutive codes of the same value, it is necessary to read code values, one at a time, and to count the number of code values. (3) A change in the length of a substring as a result of insertion or removal causes the addresses of all the data following the insertion or removal point to be increased or decreased. This is a time-consuming process. For example, FIG. 54 shows an example in which an interval of code value 1 ›6 . . . 8! is inserted immediately after the code value N at position 5 (address A+4). This insertion involves a sequence of operations; that is, data at addresses A+5 to A+15 must be moved to addresses A+8 to A+18. (4) Because a storage area large enough to contain the number of code values (that is, the number of positions), each consisting of a specified number of bits (code unit), is required, a limited storage area limits the amount of information each code unit can contain. If each code unit is allowed to represent the maximum amount of information, a huge amount of storage is required. This results in less positions and more coarse position increments (less precise). Conversely, smaller position increments increase the number of position, requiring a huge amount of storage. In this case, only discrete amounts such as integers can be represented in practice. Another method is to store pairs, each consisting of a code value and a range of a substring where that code consecutively occurs, in a consecutive storage area in the order in which the substrings appear (second method). FIG. 55 shows the code string in Table 1 stored in the second method. In the second method, the amount of memory depends on the number of consecutive code value intervals. That is, it depends, not on the number of positions, but on the number of intervals, increasing the memory efficiency. A continuous range of code values can be identified by referencing a data. In addition, the differences of the precision of each interval length (length type=discrete or continuous) are allowed. For example, floating-point numbers may be processed easily. Again, in this method, when the length of a substring (interval) or the number of substrings is changed, it is necessary to re-write all the substring data that follow the changed position. In addition, to identify the code value of a particular position, it is necessary to search the corresponding range for the position of the value, for example, using the binary search method. A binary search tree is conveniently used in the binary search method. In this method, a substring at the center of a code string is used as the root node. Each node is assigned a substring range data as well as the code value of the substring. Substring data may be represented by the start point and the end point of the range or only by the start point of the range with the end point obtaining from the start point of the next substring. FIG. 56 shows an example of a binary search tree corresponding to the data in Table 1. In this figure, each node is assigned the start point of the corresponding substring (in the circle) and the code value of the substring (below the circle). In a sub-tree consisting of nodes that are at the end, one of them (for example, the node at the left) corresponds to the substring preceding the above-described node and the right sub-tree corresponds to the substring that follows the above-described node. Again, in this case, when the position of a substring s changed, it is necessary to change all the data following the change point. It is also possible to store pairs, each consisting of a code value and the length of a substring where that code consecutively occurs, in a consecutive storage area in the order in which substrings appear (third method). FIG. 57 is an example of data stored in the conventional third method. An advantage of this method is that, when a substring is expanded or reduced, only the length of the interval of the expanded or reduced substring need be changed. A disadvantage of this method is that, when obtaining the code at a particular position, the lengths of the intervals from the start or the end to the corresponding position must be added. In addition, the binary search method cannot be used because information about a particular interval gives us only the information about the length of the interval. A linear list may be used instead. of using a consecutive area; this makes it possible to connect non-consecutive areas through pointers (fourth method). FIG. 58 shows a data structure represented in the fourth method. The fourth method eliminates the need for transferring data in memory when adding, deleting, dividing, or merging one or more intervals. However, to locate a particular position, this method still requires us to add up the lengths of intervals. This invention seeks to solve the problems associated with the prior art described above. It is an object of this invention to provide an efficient data processing system , a data retrieval system , a data processing method and a data retrieval method. More specifically, it is an object of this invention to provide a data processing system which updates data for retrieval speedily, a data processing system which process data efficiently, a data processing system which retrieves data speedily, a data processing system which uses memory efficiently, and a data retrieval system which retrieves all, but non-duplicating, data strings containing the whole or a part of a key string not longer than a specified length or of any length. SUMMARY OF THE INVENTION To achieve the above objects, an invention according to a first illustrative implementation is a data processing system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; dictionary tree generating means for generating a dictionary tree, which is a binary tree, based on the dictionary data; text data generating means for generating text data based on the code string; text tree generating means for generating a text tree, which is a binary tree, based on the text data; retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary tree and text tree; changing means for changing the code string; and updating means for updating, based on the contents of the change, the dictionary data, dictionary tree, text data, and text tree of the code string associated with the change. And an invention according to a second illustrative implementation is a data processing method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating a dictionary tree, which is a binary tree, based on said dictionary data; generating text data based on said code string; generating a text tree, which is a binary tree, based on said text data; retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary tree and text tree; changing said code string; and updating, based on the contents of said change, the dictionary data, dictionary tree, text data, and text tree of said code string associated with the change. According to the data processing system of the first illustrative implementation and the data processing method of the second illustrative implementation, configuring the dictionary tree and the text tree with a one-to-one correspondence between their items makes it easy to find all, but non-duplicating, appearances of a pattern in the text to be retrieved. An invention according to a third illustrative implementation is a data processing system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; text data generating means for generating text data based on the code string; retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary data and text data; changing means for changing the code string; and updating means for updating, based on the contents of the change, the dictionary data and text data of the code string associated with the change. And an invention according to a fourth illustrative implementation is a data processing method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating text data based on said code string; retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary data and text data; changing said code string; and updating, based on the contents of said change, the dictionary data and text data of said code string associated with the change. According to the data processing system of the third illustrative implementation and the data processing method of the fourth illustrative implementation, configuring the dictionary tree and the text tree with a one-to-one correspondence between their items makes it easy to find all, but non-duplicating, appearances of a pattern in the text to be retrieved. An invention according to a fifth illustrative implementation is a data processing system of the first illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is limited. And an invention according to a sixth illustrative implementation is a data processing system of the third illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is limited. According to the invention of the fifth and sixth illustrative implementations, limiting the length of a key-candidate substring saves the area where key-candidate substrings are stored. In addition, limiting the length of a key-candidate substring eliminates the need for redundant comparison. An invention according to a seventh illustrative implementation is a data processing system of the first illustrative implementation wherein the length of a key candidate substring constituting the dictionary data is not limited. And an invention according to an eighth illustrative implementation is a data processing system of the third illustrative implementation wherein the length of a key candidate substring constituting the dictionary data is not limited. According to the invention of the seventh and eighth illustrative implementations, not limiting the length of a key-candidate substring eliminates the need to later check the subsequent substring in the text and enables a substring of any length to be retrieved by simply retrieving from the index directly. An invention according to a ninth illustrative implementation is a data processing system of the first illustrative implementation, wherein at least one of the dictionary tree generating means and text tree generating means establishes a pointer between a node in the dictionary tree and the corresponding node in the text tree. According to the invention of the ninth illustrative implementation, a pointer established between a node in the dictionary tree and the corresponding node in the text tree makes it easier for them to reference each other. In addition, this invention saves storage space significantly because character strings need only be stored in at least one of the dictionary tree and text tree. In addition, when a character in the text is changed, the data processing system of the ninth illustrative implementation automatically changes a key-candidate substring represented by the dictionary tree by simply changing the corresponding character in the text tree, significantly reducing the time needed to update the dictionary when a character in the text is changed. When a character string consisting of one or more characters is added to the text, the invention of the ninth illustrative implementation creates, in the dictionary tree, the nodes corresponding to the key-candidate substring added to the dictionary table as a result of the addition of this character string, and establishes the pointers between the new nodes in the dictionary tree and the nodes of the characters added to the text tree, thus automatically changing the key-candidate substring represented by the dictionary tree. Therefore, when one or more characters are added to the text, this invention significantly reduces the time needed to update the dictionary. When a character string consisting of one or more characters is deleted from the text, the invention of the ninth illustrative implementation deletes, from the dictionary tree, the nodes corresponding to the key-candidate substring deleted from the dictionary table as a result of the deletion of this character string, and deletes the pointers between the nodes deleted from the dictionary tree and the nodes of the characters deleted from the text tree, thus automatically changing the key-candidate substring represented by the remaining node of the dictionary tree. Therefore, when one or more characters are deleted from the text, this invention significantly reduces the time needed to update the dictionary. An invention according to a tenth illustrative implementation is a data processing system of the third illustrative implementation, wherein at least one of the dictionary data generating means and text data generating means establishes pointers between the dictionary data and text data. According to the invention of the tenth illustrative implementation, a pointer established between a node in the dictionary data and the corresponding node in the text data makes it easier for them to reference each other. In addition, this invention saves storage space significantly because character strings need only be stored in at least one of the dictionary data and text data. In addition, when a character in the text is changed, the data processing system of the tenth illustrative implementation automatically changes a key-candidate substring represented by the dictionary tree by simply changing the corresponding character in the text data, significantly reducing the time needed to update the dictionary when a character in the text is changed. When a character string consisting of one or more characters is added to the text, the invention of the tenth illustrative implementation creates, in the dictionary data, the nodes corresponding to the key-candidate substring added to the dictionary table as a result of the addition of this character sting, and establishes the pointers between the new nodes in the dictionary data and the nodes of the characters added to the text data, thus automatically changing the key-candidate substring represented by the dictionary data. Therefore, when one or more characters are added to the text, this invention significantly reduces the time needed to update the dictionary. When a character string consisting of one or more characters is deleted from the text, the invention of the tenth illustrative implementation deletes, from the dictionary data, the nodes corresponding to the key-candidate substring deleted from the dictionary table as a result of the deletion of this character string, and deletes the pointers between the nodes deleted from the dictionary data and the nodes of the characters deleted from the text data, thus automatically changing the key-candidate substring represented by the remaining of the dictionary data. Therefore, when one or more characters are deleted from the text, this invention significantly reduces the time needed to update the dictionary. An invention according to an eleventh illustrative implementation is a data processing system of the first illustrative implementation wherein the retrieving means retrieves data by referencing both the dictionary tree and the text tree. According to the invention of the eleventh illustrative implementation, the retrieving means retrieves data by referencing both the dictionary tree and the text tree via pointers, storing a character string efficiently. An invention according to a twelfth illustrative implementation is a data processing system of the third illustrative implementation wherein the retrieving means retrieves data by referencing both the dictionary data and the text data. According to the invention of the twelfth illustrative implementation, the retrieving means references both dictionary data and text data via the pointers, storing a character string efficiently. An invention according to a 13.sup.th illustrative implementation is a data processing system of the first illustrative implementation wherein the retrieving means restores a substring based on the dictionary tree and/or the text tree. According to the invention of the 13.sup.th illustrative implementation, the retrieving means restores a substring based on the dictionary tree and/or the text tree, eliminating the need for the substring restoring means provided separately. An invention according to a 14.sup.th illustrative implementation is a data processing system of the third illustrative implementation wherein the retrieving means restores a substring based on the dictionary data and/or the text data. According to the invention of the 14.sup.th illustrative implementation, the retrieving means restores a substring based on the dictionary data and/or the text data, eliminating the need for the substring restoring means provided separately. An invention according to a 15.sup.th illustrative implementation is a data processing system of the first illustrative implementation wherein the dictionary tree generating means and text tree generating means integrate the nodes of the dictionary tree and text tree into one. According to the invention of the 15.sup.th illustrative implementation, the dictionary tree generating means and text tree generating means integrate the nodes of the dictionary tree and text tree into one, eliminating the need for the pointers between them and saving storage space. An invention according to a 16.sup.th illustrative implementation is a data processing system of the first illustrative implementation wherein a character string is stored in the dictionary tree. According to the invention of the 16.sup.th illustrative implementation, a character string stored in the dictionary tree as well as the pointers established between the dictionary tree and text tree allow the character string to be restored, eliminating the need to store the character string in the text tree and saving storage space. An invention according to a 17.sup.th illustrative implementation is a data processing system of the 16.sup.th illustrative implementation wherein the length of a character string stored in the dictionary tree is equal to the length represented by the corresponding node in the text tree. According to the invention of the 17.sup.th illustrative implementation, storing in the dictionary tree the minimum character strings required to restore the text significantly saves storage space for storing a character string in each node in the dictionary tree. An invention according to a 18.sup.th illustrative implementation is a data processing system of the first illustrative implementation wherein a character string and a node address are used as a pointer to the dictionary tree in a node in the text tree. According to the invention as claimed in a 18.sup.th illustrative implementation, the pointers to the nodes in the dictionary tree required when the text is changed need not be stored. Storing a character string in one dictionary node only, instead of storing it in a plurality of nodes, significantly saves storage space. An invention according to the 19.sup.th illustrative implementation is a data processing system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; text data generating means for generating text data based on the code string; retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary data and text data; changing means for changing the code string; updating means for updating, based on the contents of the change, the dictionary data and text data of the code string associated with the change; and adjustment range setting means for putting the changes into one unit of adjustment work. And an invention according to a 20.sup.th illustrative implementation is a data processing method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating text data based on said code string; retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary data and text data; changing said code string; updating, based on the contents of said change, the dictionary data and text data of said code string associated with the change; and putting said changes into one unit of adjustment work. According to the data processing system of the 19.sup.th illustrative implementation and the data processing method of the 20.sup.th illustrative implementation, putting a plurality of changes to a specified range into one unit of adjustment work reduces the number of re-arrange operations of trailing strings into the dictionary data. An invention according to a 21.sup.st illustrative implementation is a data processing system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; text data generating means for generating text data based on the code string; retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary data and text data; changing means for changing the code string; sequence assigning means for assigning a sequence number to each of lexicographically-registered dictionary data items; and updating means for updating, based on the contents of the change, the dictionary data, text data, and lexicographic order of the code string associated with the change. And an invention according to a 22.sup.nd illustrative implementation is a data processing method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating text data based on said code string; retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary data and text data; changing said code string; assigning a sequence number to each of lexicographically-registered dictionary data items; and updating, based on the contents of said change, the dictionary data, text data, and lexicographic order of said code string associated with the change. According to the data processing system of the 21.sup.st illustrative implementation and the data processing method of the 22.sup.nd illustrative implementation, the number of appearances of a pattern may be obtained by simply checking the positions of two items in the dictionary data. This ensures efficient retrieval. An invention according to a 23.sup.rd illustrative implementation is data processing system of the 22.sup.nd illustrative implementation wherein the retrieving means has counting means for counting the number of sub strings, each containing an identical leading string, using the sequence numbers of the first dictionary data item and the last dictionary data item. According to the invention of the 23.sup.rd illustrative implementation, the counting means checks the positions of two items in the dictionary data to find the number of appearances of a pattern. An invention according to a 24.sup.th illustrative implementation is a data retrieval system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; dictionary tree generating means for generating a dictionary tree, which is a binary tree, based on the dictionary data; text data generating means for generating text data based on the code string; and retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary tree. And an invention according to a 25.sup.th illustrative implementation is a data retrieval method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating a dictionary tree, which is a binary tree, based on said dictionary data; generating text data based on said code string; and retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary tree. According to the data retrieval system of the 24.sup.th illustrative implementation and the data retrieval method of the 25.sup.th illustrative implementation, a simply-configured data retrieval system composed of the dictionary data generating means, dictionary tree generating means, text data generating means, and retrieving means finds, within the text, the positions of all the non-duplicating appearances of a pattern to be retrieved even when the code string is not changed. An invention according to a 26.sup.th illustrative implementation is a data retrieval system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; text data generating means for generating text data based on the code string; and retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary data. And an invention according to a 27.sup.th illustrative implementation is a data retrieval method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; generating text data based on said code string; and retrieving trailing strings each containing the whole or part of a key string as the leading sting, based on said dictionary data. According to the data retrieval system of the 26.sup.th illustrative implementation and the data retrieval method of the 27.sup.th illustrative implementation, a simply-configured data retrieval system composed of the dictionary data generating means, text data generating means, and retrieving means finds, within the text, the positions of all the non-duplicating appearances of a pattern to be retrieved when the code string is not changed. An invention according to a 28.sup.th illustrative implementation is a data retrieval system of the 24.sup.th illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is limited. And an invention according to a 29.sup.th illustrative implementation is a data retrieval system of the 26.sup.th illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is limited. According to the invention of the 28.sup.th and 29.sup.th illustrative implementations, limiting the length of a key-candidate substring saves storage space where key-candidate substrings are stored. In addition, limiting the length of a key-candidate substring eliminates the need for redundant comparison. An invention according to a 30.sup.th illustrative implementation is a data retrieval system of the 24.sup.th illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is not limited. And an invention according to a 31.sup.st illustrative implementation is a data retrieval system of the 26.sup.th illustrative implementation wherein the length of a key-candidate substring constituting the dictionary data is not limited. According to the invention of the 30.sup.th and 31.sup.st illustrative implementations, not limiting the length of a key-candidate substring eliminates the need for a subsequent check on the subsequent portion of each substring in the text. This allows a substring of any length to be retrieved by simply retrieving it directly from the index. An invention according to a 32.sup.nd illustrative implementation is a data retrieval system of the 24.sup.th illustrative implementation, further comprising text tree generating means for generating a text tree, which is a binary tree, based on the text data, wherein trailing strings each containing the whole or part of a key string as the leading string are retrieved based on the dictionary tree and text tree. According to the invention of the 32.sup.nd illustrative implementation, the data retrieval system finds the positions of all the non-duplicating appearances of a pattern to be retrieved. An invention according to a 33.sup.rd illustrative implementation is data processing system comprising: dictionary data generating means for arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of the leading string and its position within the code string; retrieving means for retrieving trailing strings each containing the whole or part of a key string as the leading string, based on the dictionary data; comparing means for comparing two code strings; storing means for determining the position of a trailing string within the index and storing it in the index based on the comparison with another trailing string already registered in the index and composed of the same characters except one; changing means for changing the code string; re-arrange determining means for determining if, when part of the code string is changed, the leading string of the trailing string including the changed position of the code string must be re-arranged; and updating means for updating, based on the determination result of the comparing means and re-arrange determining means, the dictionary data of the code string associated with the change. And an invention according to a 34.sup.th illustrative implementation is a data processing method comprising the steps of: arranging lexicographically the leading strings to be used for retrieving trailing strings each of which is a trailing part of a code string on which retrieval is to be made with the use of a key string and for generating dictionary data representing pairs each consisting of said leading string and its position within said code string; retrieving trailing strings each containing the whole or part of a key string as the leading string, based on said dictionary data; comparing two code strings; determining the position of a trailing string within the index and storing it in the index based on the comparison with another trailing string already registered in the index and composed of the same characters except one; changing said code string; determining if, when part of said code string is changed, the leading string of the trailing string including the changed position of the code string must be re-arranged; and updating, based on the determination result of said comparing means and re-arrange determining means, the dictionary data of said code string associated with said change. According to the data processing system of the 33.sup.rd illustrative implementation and the data processing method of the 34.sup.th illustrative implementation, the data processing system having the comparing means and the re-arrange determining means efficiently compares code strings required when retrieving a specified code string from the index or when registering a trailing string into the index. An invention according to a 35.sup.th illustrative implementation is a data processing system of the 35.sup.th illustrative implementation wherein the retrieving means determines, based on the position of a character on which comparison was performed last, the character position where comparison is to start next, when performing binary search on an lexicographically arranged table with a code string as the key. According to the invention of the 35.sup.th illustrative implementation, the data processing system does not compare the common leading string but starts comparing the codes immediately after the last common character, increasing code string comparison efficiency. An invention according to a 36.sup.th illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, in a table arranged lexicographically with a code string as the key and when the trailing strings, generated by removing a matching leading string from two code strings, are in the table at the time both code strings are compared, the comparing means determines the relation of two code strings based on the comparison of the trailing strings of the two code strings. According to the invention of the 36.sup.th illustrative implementation, if the trailing strings of two code strings to be compared, from which the common leading string has been removed, are in the table, the data processing system compares these two trailing strings in the table instead of comparing the two code strings, increasing code comparison efficiency. An invention according to a 37.sup.th illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, when registering the leading string of the trailing string .alpha.w in a table arranged lexicographically with the leading string of the trailing string as the key, said registering means registers the leading string of .alpha.w immediately after the leading string of .beta.x, if the difference .beta. between the shortest trailing string .beta.x which is longer than the trailing string x coming immediately before w which is the longest trailing string shorter than said trailing string .alpha.w in said table and the said trailing string x coming immediately before w matches the difference .alpha. between said trailing string .alpha.w and the shorter and longest trailing string w, and registers the leading string of .alpha.w immediately before the leading string of .gamma.y, if the difference .gamma. between the shortest trailing string .gamma.y which is longer than the trailing string y coming immediately after the longest trailing string w which is shorter than said trailing string .alpha.w in said table and the trailing string y immediately after w matches the difference .alpha. between said trailing string .alpha.w and the shorter and longest trailing string w. An invention according to a 38.sup.th illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, when registering the leading string of the trailing string w in a table arranged lexicographically with the leading string of the trailing string as the key, said registering means registers the leading string of w between the leading string of x and the leading string of y if, for the trailing strings .beta.x and .gamma.y which are immediately before and after the shortest trailing string .alpha.w which is longer than said trailing string w in said table, the leading string of the longest trailing string x which is shorter than .beta.x is adjacent to the leading string of the longest trailing string y which is shorter than .gamma.y, preceded by the leading string of x in said table, and if .alpha.=.beta. or .alpha.=.gamma.. According to the inventions of the 37.sup.th and 38.sup.th illustrative implementations, if one of two trailing strings each having the same characters in all positions except one is already in the index, the data processing system compares the two differing characters in one position to determine the position in which the other trailing string is to be registered. An invention according to a 39.sup.th illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining means compares, in a table arranged lexicographically with the leading string of a trailing string as the key, the leading string immediately before and after the leading string in the table with the leading string itself, determines that, for at least the trailing string and longer trailing strings, their leading strings need not be re-arranged if the leading string is equal to or larger than the leading string immediately before and is equal to or smaller than the leading string of the leading string immediately after and, otherwise, determines that, for at least the trailing string and shorter trailing strings which contain the changed part, their leading strings must be re-arranged. An invention according to a 40.sup.th illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining means compares, in a table arranged lexicographically with the leading string of a trailing string as the key, the leading string immediately before and after the leading string in the table with the leading string itself, determines that, for at least the trailing string and shorter trailing strings, their leading strings must be re-arranged if the characters of the leading strings to the position immediately before the changed position match and, otherwise, determines that, for at least the trailing string and longer trailing strings which contain the changed part, their leading strings need not be re-arranged. An invention according to a 41.sup.st illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining means determines, in a table arranged lexicographically with the leading string of a trailing string as the key, if the leading strings of trailing strings containing the changed part must be re-arranged, in order of the leading strings of shorter trailing strings. An invention according to a 42.sup.nd illustrative implementation is a data processing system of the 33.sup.rd illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining means determines, in a table arranged lexicographically with the leading string of a trailing string as the key, if the leading strings of trailing strings containing the changed part must be re-arranged while selecting leading strings in binary search mode, one at a time, from those arranged in order of start positions. According to the inventions of the 39.sup.th to 42.sup.nd illustrative implementations, whether or not the leading string of a trailing string which contain the changed part is to be re-arranged can be determined easily when a part of the code string is changed. An invention according to a 43.sup.rd illustrative implementation is a data retrieval system comprising: retrieving means for retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string; and index generating means for generating the index. And an invention according to the 44.sup.th illustrative implementation is a data retrieval method comprising the steps of: retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string; and generating said index. According to the data retrieval system of the 43.sup.rd illustrative implementation and the data retrieval method of the 44.sup.th illustrative implementation, a simply-structured data retrieval system and the data retrieval method, which does not generate text, can be configured. An invention according to a 45.sup.th illustrative implementation is a data processing system comprising: retrieving means for retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string; and updating means for updating, based on a change to the code string, the index of the code string associated with the change. And an invention according to a 46.sup.th illustrative implementation is a data processing method comprising the steps of: retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string; and updating, based on a change to said code string, the index of said code string associated with the change. According to the data processing system of the 45.sup.th illustrative implementation and the data processing method of the 46.sup.th illustrative implementation, a simply-structured data processing system and the data processing method, which does not generate text, can be configured. An invention according to a 47.sup.th illustrative implementation is a data processing system comprising: retrieving means for retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string; index generating means for generating the index; changing means for changing the code string; and updating means for updating, based on a change to the code string, the index of the code string associated with the change. And an invention according to a 48.sup.th illustrative implementation is a data processing method comprising the steps of: retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string; generating said index; changing said code string; and updating, based on a change to said code string, the index of said code string associated with the change. According to the data processing system of the 47.sup.th illustrative implementation and the data processing method of the 48.sup.th illustrative implementation, a simply-structured data processing system and the data processing method, which does not generate text, can be configured. An invention according to a 49.sup.th illustrative implementation is a data retrieval system comprising: retrieving means having a retrieving function for retrieving a trailing string of a code string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code string, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string, and having a restoring function for restoring the whole or part of a code string beginning in the specified position, based on a text composed of pairs, each consisting of a leading string of a trailing string residing in the trailing part of the code string and its position within the code string, arranged in order of appearance of the leading string within the code string; index generating means for generating the index; and text generating means for generating the text. And an invention according to a 50.sup.th illustrative implementation is a data retrieval method comprising the steps of: retrieving a trailing string of a code string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code string, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string, restoring the whole or part of a code string beginning in the specified position, based on a text composed of pairs, each consisting of a leading string of a trailing string residing in the trailing part of said code string and its position within said code string, arranged in order of appearance of the leading string within said code string; generating said index; and generating said text. According to the data retrieval system of the 49.sup.th illustrative implementation and the data retrieval method of the 50.sup.th illustrative implementation, an efficient data retrieval system and the data retrieval method, which can compare two substrings easily and can restore the whole or a part of a code string, can be configured. An invention according to a 51.sup.st illustrative implementation is a data processing system comprising: retrieving means having a retrieving function for retrieving a trailing string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code string, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string, having a function for retrieving the leading string of a trailing string residing in the trailing part of the code string, and having a restoring function for restoring the whole or part of a code sting beginning in the specified position, based on a text arranged in order of positions within the code string; and updating means for updating, based on a change to the code string, the index and the text of the code string associated with the change. And an invention according to a 52.sup.nd illustrative implementation is a data processing method comprising the steps of: retrieving a trailing string of a code string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code string, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string, retrieving the leading string of a trailing string residing in the trailing part of said code string, restoring the whole or part of a code string beginning in the specified position, based on a text arranged in order of positions within said code string; and updating, based on a change to said code string, the index and the text of said code string associated with the change. According to the data processing system of the 51.sup.st illustrative implementation and the data processing method of the 52.sup.nd illustrative implementation, an efficient data processing system and the data processing method, which can compare two substrings easily and can restore the whole or a part of a code string, can be configured. An invention according to a 53.sup.rd illustrative implementation is a data processing system comprising: retrieving means having a retrieving function for retrieving a trailing string of a code string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within the code string, arranged lexicographically by the leading string, for a code string on which retrieval is performed with the use of a key string, having a function for retrieving the leading string of a trailing string residing in the trailing part of the code string, and having a restoring function for restoring the whole or part of a code string beginning in the specified position, based on a text arranged in order of positions within the code string; index generating means for generating the index; text generating means for generating the text; changing means for changing the code string; and updating means for updating, based on a change to the code string, the index and the text of the code string associated with the change. And an invention according to a 54.sup.th illustrative implementation is a data processing method comprising the steps of: retrieving a trailing string of a code string containing the whole or part of a key string as the leading string, based on an index composed of pairs, each consisting of a leading string to be used for retrieving the trailing string and its position within said code string, arranged lexicographically by said leading string, for a code string on which retrieval is performed with the use of a key string, retrieving the leading string of a trailing string residing in the trailing part of said code string, restoring the whole or part of a code string beginning in the specified position, based on a text arranged in order of positions within said code string; generating said index; generating said text; changing said code string; and updating, based on a change to said code string, the index and the text of said code string associated with the change. According to the data processing system of the 53.sup.rd illustrative implementation and the data processing method of the 54.sup.th illustrative implementation, an efficient data processing system and the data processing method, which can compare two substrings easily, can restore the whole or a part of a code string, and can update an index and text according to a change in the code string, can be configured. An invention according to a 55.sup.th illustrative implementation is a data retrieval system of the 43.sup.rd or 49.sup.th illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving means has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, and wherein the index generating means generates index items to which sequence numbers are assigned. According to the invention of the 55.sup.th illustrative implementation, a data retrieval system, which can easily find the number of substrings satisfying the retrieval condition, may be built by assigning sequence numbers to index items, by providing the function for counting the number of trailing strings containing the whole or a part of the key string as their leading strings based on the sequence, and by making the index generating means to generate index items to which sequence numbers are assigned. An invention according to a 56.sup.th illustrative implementation is a data processing system of the 45.sup.th or 51.sup.st illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving means has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, and wherein the updating means updates the sequence too. According to the invention of the 56.sup.th illustrative implementation, a data processing system, which can easily find the number of substrings satisfying the retrieval condition even when the code string has been changed, may be built by assigning sequence numbers to index items, by providing a function for outputting the number of trailing strings containing the whole or a part of the key string as their leading strings based on the sequence, and by making the updating means update the sequence too. An invention according to a 57.sup.th illustrative implementation is a data processing system of the 47.sup.th or 53.sup.rd illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving means has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, wherein the index generating means generates index items to which sequence numbers are assigned, and wherein the updating means updates the sequence too. According to the invention of the 57.sup.th illustrative implementation, a data processing system, which can easily find the number of substrings satisfying the retrieval condition even when the code string has been changed, may be built by assigning sequence numbers to index items, by providing, in the retrieving means, a function for outputting the number of trailing strings containing the whole or a part of the key string as their leading strings based on the sequence, by causing the index generating means to generate index items to which sequence numbers are assigned, and by making the updating means update the sequence too. An invention according to a 58.sup.th illustrative implementation is a data retrieval system of the 43.sup.rd or 49.sup.th illustrative implementations wherein the length of a key-candidate substring constituting the index is limited. An invention according to a 59.sup.th illustrative implementation is a data processing system of the 45.sup.th, 47.sup.th, 51.sup.st or 53.sup.rd illustrative implementations wherein the length of a key-candidate substring constituting the index is limited. According to the inventions of the 58.sup.th and 59.sup.th illustrative implementations, limiting the length of a key-candidate substring saves storage space where key-candidate substrings are stored. At the same time, limiting the length of a key-candidate substring eliminates the need for redundant comparison. An invention according to a 60.sup.th illustrative implementation is a data retrieval system of the 43.sup.rd or 49.sup.th illustrative implementations wherein the length of a key-candidate substring constituting the index is not limited. An invention according to a 61.sup.st illustrative implementation is a data processing system of the 45.sup.th, 47.sup.th, 51.sup.st, or 53.sup.rd illustrative implementations wherein the length of a key-candidate substring constituting the index is not limited. According to the inventions of the 60.sup.th and 61.sup.st illustrative implementations, not limiting the length of a key-candidate substring eliminates the need for a subsequent check on the subsequent portion of each substring in the text. This allows a substring of any length to be retrieved simply by retrieving it directly from the index. An invention according to a 62.sup.nd illustrative implementation is a data processing system of the 53.sup.rd illustrative implementation wherein the pairs in the index and the pairs in the text are integrated. An invention according to a 63.sup.rd illustrative implementation is a data retrieval system of the 49.sup.th illustrative implementation wherein the pairs in the index and the pairs in the text are integrated. According to the inventions of the 62.sup.nd and 63.sup.rd illustrative implementations, integrating the pairs of index nodes and text nodes significantly reduces the required storage space. An invention according to a 64.sup.th illustrative implementation is a data processing system of the 59.sup.th illustrative implementation wherein the index is represented by a binary tree. An invention according to a 65.sup.th illustrative implementation is a data processing system of the 61.sup.st illustrative implementation wherein the index is represented by a binary tree. An invention according to a 66.sup.th illustrative implementation is a data retrieval system of the 58.sup.th illustrative implementation wherein the index is represented by a binary tree. An invention according to a 67.sup.th illustrative implementation is a data retrieval system of the 60.sup.th illustrative implementation wherein the index is represented by a binary tree. According to the inventions of the 64.sup.th trough 67.sup.th illustrative implementations, representing the index as a binary tree significantly increases retrieval efficiency. An invention according to a 68.sup.th illustrative implementation is a data processing system of the 59.sup.th illustrative implementation wherein the text is the code string stored in contiguous addresses, each location being represented by an address. An invention according to a 69.sup.th illustrative implementation is a data processing system of the 61.sup.st illustrative implementation wherein the text is the code string stored in contiguous addresses, each location being represented by an address. An invention according to a 70.sup.th illustrative implementation is a data retrieval system of the 58.sup.th illustrative implementation wherein the text is the code string stored in contiguous addresses, each location being represented by an address. An invention according to a 71.sup.st illustrative implementation is a data retrieval system of the 60.sup.th illustrative implementation wherein the text is the code string stored in contiguous addresses, each location being represented by an address. According to the inventions of the 68.sup.th through 71.sup.st illustrative implementations, storing the code string in contiguous addresses and representing the positions with addresses reduces the required storage space and increases text retrieval efficiency. An invention according to a 72.sup.nd illustrative implementation is a data processing system of the 45.sup.th, 46.sup.th, 51.sup.st and 53.sup.rd illustrative implementations wherein the updating means combines the updates for a plurality of changes to the code string into one unit of work. According to the invention of the 72.sup.nd illustrative implementation, combining a plurality of changes to the code string significantly increases update efficiency. An invention according to a 73.sup.rd illustrative implementation is data processing method of the 22.sup.nd illustrative implementation wherein the retrieving step has counting step for counting the number of substrings, each containing an identical leading string, using the sequence numbers of the first dictionary data item and the last dictionary data item. According to the invention of the 73.sup.rd illustrative implementation, the counting step checks the positions of two items in the dictionary data to find the number of appearances of a pattern. An invention according to a 74.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein the retrieving step determines, based on the position of a character on which comparison was performed last, the character position where comparison is to start next, when performing binary search on an lexicographically arranged table with a code string as the key. According to the invention of the 74.sup.th illustrative implementation, the data processing method does not compare the common leading string but starts comparing the codes immediately after the last common character, increasing code string comparison efficiency. An invention according to a 75.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, in a table arranged lexicographically with a code string as the key and when the trailing strings, generated by removing a matching leading string from two code strings, are in the table at the time both code strings are compared, the comparing step determines the relation of two code strings based on the comparison of the trailing strings of the two code strings. According to the invention of the 75.sup.th illustrative implementation, if the trailing strings of two code strings to be compared, from which the common leading string has been removed, are in the table, the data processing method compares these two trailing strings in the table instead of comparing the two code strings, increasing code comparison efficiency. An invention according to a 76.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, when registering the leading string of the trailing string .alpha.w in a table arranged lexicographically with the leading string of the trailing string as the key, said registering step registers the leading string of .alpha.w immediately after the leading string of .beta.x, if the difference .beta. between the shortest trailing string .beta.x which is longer than the trailing string x coming immediately before w which is the longest trailing string shorter than said trailing string .alpha.w in said table and the said trailing string x coming immediately before w matches the difference .alpha. between said trailing string .alpha.w and the shorter and longest trailing string w, and registers the leading string of .alpha.w immediately before the leading string of .gamma.y, if the difference .gamma. between the shortest trailing string .gamma.y which is longer than the trailing string y coming immediately after the longest trailing string w which is shorter than said trailing string .alpha.w in said table and the trailing string y immediately after w matches the difference .alpha. between said trailing string .alpha.w and the shorter and longest trailing string w. An invention according to a 77.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, when registering the leading string of the trailing string w in a table arranged lexicographically with the leading string of the trailing string as the key, said registering step registers the leading string of w between the leading string of x and the leading string of y if, for the trailing strings .beta.x and .gamma.y which are immediately before and after the shortest trailing string .alpha.w which is longer than said trailing string w in said table, the leading string of the longest trailing string x which is shorter than .beta.x is adjacent to the leading string of the longest trailing string y which is shorter than .gamma.y, preceded by the leading string of x in said table, and if .alpha.=.beta. or .alpha.=.gamma.. According to the inventions of the 76.sup.th and 77.sup.th illustrative implementations, if one of two trailing strings each having the same characters in all positions except one is already in the index, the data processing method compares the two differing characters in one position to determine the position in which the other trailing string is to be registered. An invention according to a 78.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining step compares, in a table arranged lexicographically with the leading string of a trailing string as the key, the leading string immediately before and after the leading string in the table with the leading string itself, determines that, for at least the trailing string and longer trailing strings, their leading strings need not be re-arranged if the leading string is equal to or larger than the leading string immediately before and is equal to or smaller than the leading string of the leading string immediately after and, otherwise, determines that, for at least the trailing string and shorter trailing strings which contain the changed part, their leading strings must be re-arranged. An invention according to a 79.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining step compares, in a table arranged lexicographically with the leading string of a trailing string as the key, the leading string immediately before and after the leading string in the table with the leading string itself, determines that, for at least the trailing string and shorter trailing strings, their leading strings must be re-arranged if the characters of the leading strings to the position immediately before the changed position match and, otherwise, determines that, for at least the trailing string and longer trailing strings which contain the changed part, their leading strings need not be re-arranged. An invention according to an 80.sup.th illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining step determines, in a table arranged lexicographically with the leading string of a trailing string as the key, if the leading strings of trailing strings containing the changed part must be re-arranged, in order of the leading strings of shorter trailing strings. An invention according to an 81.sup.st illustrative implementation is a data processing method of the 34.sup.th illustrative implementation wherein, after part of the code string has been changed, the re-arrange determining step determines, in a table arranged lexicographically with the leading string of a trailing string as the key, if the leading strings of trailing strings containing the changed part must be re-arranged while selecting leading strings in binary search mode, one at a time, from those arranged in order of start positions. According to the inventions of the 78.sup.th to 81.sup.st illustrative implementations, whether or not the leading string of a trailing string which contain the changed part is to be re-arranged can be determined easily when a part of the code string is changed. An invention according to an 82.sup.nd illustrative implementation is a data retrieval method of the 44.sup.th and 50.sup.th illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving step has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, and wherein the index generating step generates index items to which sequence numbers are assigned. According to the invention of the 82.sup.nd illustrative implementation, a data retrieval method, which can easily find the number of substrings satisfying the retrieval condition, may be built. An invention according to an 83.sup.rd illustrative implementation is a data processing method of the 46.sup.th and 52.sup.nd illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving step has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, and wherein the updating step updates the sequence too. According to the invention of the 83.sup.rd illustrative implementation, a data processing method, which can easily find the number of substrings satisfying the retrieval condition even when the code string has been changed, may be built. An invention according to an 84.sup.th illustrative implementation is a data processing method of the 48.sup.th or 54.sup.th illustrative implementations wherein the index has items to which sequence numbers are assigned, wherein the retrieving step has an output function for outputting, based on the sequence, the number of trailing strings each of which contains the whole or part of a specific key string, wherein the index generating step generates index items to which sequence numbers are assigned, and wherein the updating means updates the sequence too. According to the invention of the 84.sup.th illustrative implementation, a data processing method, which can easily find the number of substrings satisfying the retrieval condition even when the code string has been changed, may be built. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a funct | ||||||