JP3765459B2 - XML document search device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an XML document search apparatus, and in particular, searches for desired data from an XML (eXtensible Markup Language) database even if a user does not know a tag type (DTD: Document Type Definition) of a document type to be searched. The present invention relates to an XML document search apparatus capable of performing the above.
[0002]
[Prior art]
In recent years, XML has attracted attention as a language for describing and exchanging documents on the Internet or an intranet. Unlike HTML, XML uses a tag for describing a document having a structure, so that the document can be described and managed in units of small elements rather than as a unit. To date, several databases have been published for storing and retrieving documents written in XML. For example, there is a product named eXcelon from Object Design.
[0003]
In an XML document, since tags can be freely defined and used by users, a common DTD is not used among all users, but a DTD uniquely defined / extended by an information sender is used. A document may be described. As a result, on the Internet or an intranet, XML documents having DTDs that are structurally different but having semantically similar DTDs are scattered.
[0004]
FIG. 6 shows two types of DTDs that are structurally different but semantically similar, and examples of XML documents and search formulas based on the examples. FIG. 6A shows a DTD that defines each tag of paper, title, author, and date (the tag name is called an element name), and shows that paper includes the remaining three. On the other hand, (a ′) in the figure shows a DTD that defines each tag of article, title, page, and writer, and shows that article includes the remaining three.
[0005]
FIG. 6B shows the representation of the XML document, which shows that it follows DTD starting from paper (root element name), and that the value for each element name is SAMPLE TITLE, john, 1103. FIG. 4B 'shows that DTD is followed starting from article, and that the value for each element name is SAMPLE TITLE, 123, john.
[0006]
Further, FIG. 6C shows a retrieval formula described in XML-QL, in which the value of title is acquired from an XML document in which paper is the root element name and the value of author is john. Further, (c ′) in the figure shows that a Title value is acquired from an XML document in which article is the root element name and the writer value is john.
[0007]
FIG. 9 is an explanatory diagram of an example of document search using the XML database. The process configuration includes a database client 31 that accepts a user search request and sends a request to the database in a database operation language, and an XML database 32 that stores an XML document and provides an operation in the database operation language to the outside. In this conventional configuration, when a user or an application program tries to acquire the entire document or a part thereof from the database, the user or the like has all types (for example, paper type and article type) where the target document is likely to exist. It is necessary to understand each DTD and issue a search operation for each of those types, as shown by 33 and 34 shown in the figure.
[0008]
[Problems to be solved by the invention]
As described above, XML databases having different DTDs that are structurally different on the Internet or an intranet are scattered, but a user or an application program tries to retrieve an XML document from the XML database. Then, it is necessary to separately describe a search expression for all DTD documents that are considered to have a necessary value, and there is a problem that it is not efficient.
[0009]
For example, taking Fig. 9 as an example, if you want to know the title of a book written by Mr. John, the document defined by paper and article is different in the XML database, so for each of paper and articl Thus, it is necessary to separately inquire by describing a search expression as indicated by 33 and 34 in FIG.
For this reason, there is also a problem that the cost increases as the number of documents described based on different DTDs increases.
[0010]
The object of the present invention is to eliminate the above-mentioned problems of the prior art and to improve the efficiency of the XML database having a DTD that is structurally different but having a DTD that is semantically similar without being aware of the difference in DTD. It is an object of the present invention to provide an XML document search apparatus that can search automatically.
[0011]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides an XML document search apparatus for searching a desired document from an XML document, means for extracting a tag element name from an input search expression, and the extracted Means for extracting a synonym of an element name; and means for comparing the synonym with a category index corresponding to a tag definition (DTD) of an XML database, and obtaining an element name of a tag that matches the synonym from the category index; And a means for creating an output search expression using the element name of the tag acquired from the category index, and the XML database is searched using the output search expression. is there.
[0012]
According to this invention, the input search expression is for output having an element name corresponding to the tag definition of the document existing in the XML database based on the synonym of the element name of the tag described in the search expression. Therefore, the database client does not need to know the DTD of the document type to be searched, and the search procedure is simplified and the search range can be expanded.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of an XML document search system of the present invention.
As shown in FIG. 1, the XML document search system includes an XML document search device 1, an XML database 2, and a database client 3.
[0014]
The XML document search apparatus 1 includes an input analysis unit 11 that receives and analyzes an input from the outside, a category analogy unit 12 that receives a set of elements and outputs a category name that characterizes the set of elements, and an XML database 2. Category index management unit 14 for managing the category index 13 corresponding to the DTD information, a synonym extraction unit 15 for outputting a plurality of synonyms of the given keyword, and an output synthesis unit for sending processing results of the search device 1 to the outside 16 and a central control unit 17 that performs overall control of each unit.
[0015]
The configuration of the XML document search apparatus 1 will be described in more detail. The input analysis unit 11 receives a database operation request from the database client 3 and extracts an operation request parameter. Also, a response from the XML database 2 is accepted. The category analogy unit 12 receives a set of elements belonging to the same element name from the central control unit 17, estimates the category names that characterize the element set, and sends the most reliable one to the central control unit 17. . The category index management unit 14 manages the category index 13 corresponding to the DTD information in the XML database 2.
[0016]
The category index 13 uses a “category name” characterizing a set of elements corresponding to a tag having a DTD as an index key and an actual DTD corresponding to the “category name” as a value. The “category name” is derived from the values in the actual XML database 2 by analogy using a thesaurus.
[0017]
The synonym extraction unit 15 outputs a plurality of synonyms of the given keyword. An existing thesaurus DB or the like can be used. For example, a thesaurus DB such as QZS Dictionary Server can be used. The output synthesizing unit 16 receives parameters of a search expression that is a processing result made by the XML document search apparatus 1 in response to a database operation request made by the database client 3, and synthesizes a plurality of search expressions to the XML database 2 To send. Also, the response from the XML database 2 transferred from the input analysis unit 11 is sent to the database client 3. The central control unit 17 receives parameters from the input analysis unit 11 and performs database operation processing and category index construction / change processing using the category analogy unit 12, the category index management unit 14, and the synonym extraction unit 15, The result is sent to the output composition unit 16.
[0018]
Next, the operation of the XML document search apparatus 1 having the above configuration will be described below. First, the operation performed by the central control unit 17 when the XML document retrieval apparatus 1 is first connected to the XML database 2 will be described with reference to the flowchart of FIG. 2 and the specific example of FIG. This operation is an operation for constructing the category index 13 from the values in the actual XML database 2.
[0019]
In step S 1, all root element names and corresponding types (DTD) are acquired from the XML database 2, and a DTD registration request is issued to the category index management unit 14. The category index management unit 14 registers DTD in the category index 13. In the example of FIG. 3, the root element name “paper” stored in the XML database 2 and the corresponding DTD “paper, title, author, date”, the next root element name “article” and the corresponding DTD “ “article, Title, page, writer” and the next root element name “trip” and the corresponding DTD “destination, department, arrival”,... are acquired from the XML database 2 and temporarily registered in the category index 13.
[0020]
In step S2, an arbitrary number of documents (data) is acquired from the XML database 2 for a certain root element name among the root element names. In the example of FIG. 3, the documents “SAMPLE, john, 9701”, “SAMPLE2, john, 9811”, etc. corresponding to the root element name “paper” are acquired from the XML database 2.
[0021]
In step S3, the acquired plurality of documents are sent to the category analogy unit 12, and category names representing the plurality of sent documents are acquired. The category analogy unit 12 infers a category name representing it based on a plurality of documents, and sends the most reliable one (cname) to the central control unit 17. In the example of FIG. 3, it is assumed that the category analogy unit 12 analogizes the category name “book” from the documents “SAMPLE, john, 9701” and “SAMPLE2, john, 9811”.
[0022]
In step S4, a registration request for the cname is issued to the category index management unit 14. The category index management unit 14 registers and manages the cname in the category index 13 in association with the root element name. In the example of FIG. 3, “book” as cname is associated with the root element name “paper” and registered in the category index 13.
[0023]
In step S5, it is determined whether or not cname is associated with all the root element names. If this determination is negative, the process returns to step S2 to repeat the above operation. In the example of FIG. 3, next, the documents “Flower, 101, thomas”, “Animals, 100, tom”, “Database, 56, john” corresponding to the root element name “article” are acquired. The name “book” is inferred, and “book” which is cname is associated with the root element name “article” and registered in the category index 13.
[0024]
When the above process is repeated and the determination in step S5 is affirmative, the category index construction process ends. With the above operation, for example, the category index 13 as shown in FIG. 5 is created.
[0025]
It is necessary to maintain the constructed category index by changing it with the insertion or update of the data type, or improving the accuracy of the category name as the number of stored documents increases or changes. The update of the category name is performed by the central control unit 17, the category index management unit 14, and the category analogy unit 12 triggered by a data operation or a data type operation.
[0026]
Next, the data search processing operation of the XML document search apparatus 1 will be described with reference to the flowchart of FIG. 4 and the explanatory diagram of FIG.
In step S11, it is determined whether or not a search expression has been input by the search operation of the database client 3. If this determination becomes affirmative, the process proceeds to step S12, and a certain number i is set to 1. In step S13, a root element name, a parameter element name, and a value thereof are extracted from the search formula 21. Let x be the number of extracted parameters (root element name + parameter element name).
[0027]
For example, as shown in FIG. 5, if a search formula 21 is input from the database client 3, the search formula is sent to the central control unit 17 through the input analysis unit 11. The central control unit 17 obtains the root element name “document”, the “author” corresponding to the element name of the parameter, the value “john”, and the other element name “title” from the search expression 21. Extract. In this case, the parameter number x = 3.
[0028]
In step S14, the extracted root element name and the element name of the parameter are passed to the synonym extraction unit 15, and each synonym is acquired. In the example of FIG. 5, “document” as the root element name and “author” and “title” as parameter element names are passed to the synonym extraction unit 15. Then, the synonym extraction unit 15 returns a synonym corresponding to the root element name and the element name of the parameter to the central control unit 17. In addition, as this synonym extraction part 15, commercially available thesaurus DB23 can be used.
[0029]
In step S15, a synonym of the root element name, for example, a book, paper, paper, document, article, or the like that is a synonym of the “document” is sent to the category index 13 through the category index management unit 14, and from the category index 13, A root element name and DTD having the synonym as a category name are acquired. In the example of FIG. 5, the root element names “paper” and “article” corresponding to the category index “book” are acquired from the category index 13. Also, a DTD corresponding to each root element name is acquired.
[0030]
In step S16, it is determined whether or not a synonym group of the root element name exists in the category index. When this determination is negative, the process is terminated. On the other hand, if the determination is affirmative, the process proceeds to step S17, where the number of root element names acquired from the category index is k, the DTD of the i-th root element name is acquired, and matches the synonym in the DTD. Select an element name. At this time, the number of selected element names is y.
[0031]
In the example of FIG. 5, the DTD “paper, title, author, date” of the root element name “paper” is acquired, and the synonyms “author, writer, Author,... , title, Theme, ... "is selected from the DTD. In this example, “paper, title, author” matches, so “paper, title, author” is selected.
[0032]
In step S18, it is determined whether or not the number y of matched element names is equal to the number of parameters x extracted from the search expression. If this determination is affirmative, the process proceeds to step S19, and an output search is performed. Create one expression. In the example of FIG. 5, one output search expression is created using “paper, title, author”.
[0033]
In step S20, it is determined whether i ≧ k is satisfied. When this determination is negative and when the determination in step S18 is negative, the process proceeds to step S21 and 1 is added to i. Then, returning to step S17, the DTD of the next root element name (“article” in the example of FIG. 5) is acquired, and the element name that matches the synonym is selected in the DTD. In this example, “article, writer, Title” is selected. When the above operation is repeated and the determination in step S20 becomes affirmative, the process proceeds to step S22, and the output combining unit 16 combines the output search expressions. In the example of FIG. 5, the output search formulas 22a and 22b are obtained by this synthesis.
[0034]
In step S23, the search expressions 22a and 22b are sent to the XML database 2. In step S24, responses from the XML database 2 are collected and sent to the output synthesis unit 16 via the input analysis unit 11, and in step S25, the collection results are sent from the output synthesis unit 16 to the database client 3.
[0035]
As described above, according to the above-described embodiment, the user can efficiently search the XML database without being aware of the difference or arrangement of the DTD element names.
[0036]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an explanatory diagram of the operation of constructing the category index 13. In this embodiment, an arbitrary number or all of root element names and corresponding DTDs stored therein are acquired from the XML database 2 without using the category analogy unit 12 as shown in FIG. This is registered in the category index 13. According to this method, the root element name and DTD having contents as shown in FIG. 7 are registered as the category index 13.
[0037]
Next, the operation of the data search process of the XML document search apparatus 1 will be described with reference to FIG. The operation of this embodiment is different from the operation of FIG. 5 in that the central control unit 17 searches for the root element name in the category index 13 based on the synonym of the root element name acquired from the synonym extraction unit 15. In particular, the other points are the same as in FIG.
[0038]
According to this embodiment, the accuracy of the XML database search is considered to be slightly lower than that of the first embodiment, but has the advantage that the category index 13 can be constructed with a simple configuration and at a low cost. .
[0039]
【The invention's effect】
As is apparent from the above description, according to the present invention, the element name of the tag is extracted from the input search expression, and the element name is stored in the XML database based on the synonym. Therefore, the user does not need to know the DTD of the document type of the XML database to be searched in advance, and can easily create the search expression. it can. Therefore, the user can efficiently search, and can acquire the search result with high accuracy.
[0040]
Further, the category index is automatically updated when there is an update such as addition, change, or deletion in the document of the XML database, so that it can be maintained in the best state without any maintenance.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of category index construction according to the first embodiment of this invention.
FIG. 3 is an operation explanatory diagram of category index construction according to the first embodiment.
FIG. 4 is a flowchart showing the data search processing operation of the XML document search apparatus according to the first embodiment of the present invention.
FIG. 5 is an operation explanatory diagram of data search processing of the XML document search apparatus of the first embodiment.
FIG. 6 is an operation explanatory diagram of category index construction according to the second embodiment of this invention.
FIG. 7 is an operation explanatory diagram of a data search process of the XML document search device according to the second embodiment of the present invention.
FIG. 8 is an explanatory diagram of an example of a DTD, an XML document, and a search expression;
FIG. 9 is an explanatory diagram of a conventional XML document search method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... XML document search apparatus, 2 ... XML database, 3 ... Database client, 11 ... Input analysis part, 12 ... Category analogy part, 13 ... Category index, 14 ... Category index management part, 15 ... Synonym extraction part, 16 ... Output Synthesizer, 21... Input search formula, 22a, 22b... Output search formula.

Claims (5)

In an XML document search apparatus for searching a desired document from a plurality of XML documents,
Means for extracting the element name of the tag from the input search expression;
Means for extracting a synonym of the extracted element name;
Means for comparing the synonym with a category index corresponding to a tag definition (DTD) of the XML database, and obtaining an element name of a tag matching the synonym from the category index;
Means for creating a search expression for output using the element name of the tag acquired from the category index,
An XML document search apparatus, wherein the XML database is searched using the search expression for output. The XML document search device according to claim 1,
The XML document search apparatus characterized in that the inputted search expression has a root element name, and an element name of a tag that matches a synonym of the root element name is obtained from the category index. The XML document search device according to claim 1 or 2,
The category index includes a category name and an element name of a tag positioned below the category name. The synonym of the root element name of the input search expression is compared with the category name of the category index, and the two match. XML document search, wherein a synonym of an element name further subordinate to the root element name is compared with an element name of a tag related to the category name of the category index. apparatus. The XML document search device according to claim 3,
The XML document search apparatus according to claim 1, wherein the category name of the category index is determined by analogy based on a plurality of documents stored in the XML database. In the XML document search device according to any one of claims 1 to 4,
2. The XML document search apparatus according to claim 1, wherein the category index is updated with a change in the contents of the XML database.

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