JP4568267B2 - Structured document retrieval system and database management program - Google Patents

Description

  The present invention relates to a structured document retrieval system and a database management program suitable for retrieving a structured document.

  In a document in an XML (Extensible Markup Language) format, that is, a structured document represented by an XML document, a hierarchical structure (logical structure) of the document is expressed by a character string called a tag. Specifically, the text is structured by surrounding the text with a set of tags (a set of start tags and end tags). The character string from the start tag to the end tag is called an element including the tag, and the character string surrounded by the start tag to the end tag is called an element content. A structured document (XML document) can be expressed by a tree structure. In the tree structure of a structured document, a node corresponding to an element of the structured document is called an element node, and a node corresponding to the content of the element when the element content (value) is text is called a text node. A text node consists only of text. That is, text node = value of text node = text.

  With the spread of XML, an inquiry language (query expression) for making an inquiry to a server (database server) that manages an XML database, such as SQL (Structured Query Language) in a relational database, has been studied or formulated. As one of such inquiry languages, XQuery which is formulated by the WWW (World Wide Web) consortium is known.

  For example, Patent Document 1 discloses a structured document search (management) system that applies a structured document query language (structured document query expression) such as XQuery. In such a system, a client (client terminal) makes an inquiry to a database server using XQuery by executing a predetermined application. The database server executes a search (XQuery search) according to this inquiry. Then, the database server returns a necessary XML document (XML document data) designated by XQuery to the client as a search result (XQuery search result). As a result, the client can acquire a necessary XML document as an XQuery search result. The XML document acquired here is a part of the XML document (structured document), the whole, or a new type of XML document including a plurality of parts of the XML document.

  Moreover, in a system (structured document search system) that manages a large number of structured documents and manages a large number of structured documents, such as a database management system (DBMS) that operates on a database server, As described in Patent Document 1 or Patent Document 2, for example, it is common to apply a technique for improving the search speed using an index created in advance.

  In some cases, a plurality of XML documents or structural parts (nodes) in the XML document are searched from the XML document database, and a new XML document is created by combining the search results. In such a case, conventionally, the following first or second method is generally applied.

  The first method is characterized by using the XQuery FLWOR (FOR, LET, WHERE, ORDER BY, RETURN) expression. The client uses the XQuery FLWOR expression to cause the database server to search for a plurality of structural parts constituting a new XML document to be created, and to combine the searched multiple structural parts. An XML document can be created. That is, by using the XQuery FLWOR expression, the client can acquire a new XML document in which a plurality of structural parts specified by the FLWOR expression are combined from the database server. Here, it can be said that the structural part to be searched is also one XML document because of the structural features of the XML document.

On the other hand, the second method is characterized in that it uses structure designation information that designates an arbitrary document structure called XPath. In this second method, the client sequentially acquires a plurality of structure parts (XML documents) constituting a new XML document to be created by using an XPath corresponding to each of the target structure parts. Request a search from the server. Each time a search is requested from a client, the database server searches for the structure portion (XML document) specified by the corresponding XPath and returns it to the client. As a result, the client acquires a structure portion (XML document) corresponding to each XPath as a search result. The client obtains the obtained search result by an application process using XSLT (XSL Transformations) which is a transformation language to a document object model (DOM) or XML style sheet language (Extensible Stylesheet Language: XSL). In combination, a target new XML document is created.
JP 2005-227851 A Japanese Patent No. 3754253

  In the first method, the client uses the XQuery FLWOR expression to search the database server for a plurality of XML documents or structural parts (nodes) in the XML document and the search results. New XML documents can be created. However, for this purpose, the client needs to create (describe) an XQuery having a complicated structure (that is, a query expression for a structured document) by application processing. This hinders efficient application development.

  On the other hand, in the second method, the client sequentially searches the database server using the corresponding Xpath (Xpath expression) for searching each of a plurality of XML documents or structural parts (nodes) in the XML document. It is necessary to obtain a search result from the server each time. For this reason, the second method causes an increase in the amount of traffic (traffic amount) between the client and the database server. In addition, the client needs to create a target new XML document by combining the acquired search results by application processing using DOM / XSLT. This complicates application processing on the client and hinders efficient application development.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to search a plurality of structured documents or a structure portion in a structured document and create a new structured document in which the search results are combined. Another object of the present invention is to provide a structured document search system and database management program that can be executed without imposing a burden on application processing on the client side.

According to one aspect of the present invention, a structured document retrieval system is provided. The structured document search system includes a structured document database that stores a plurality of structured documents including a structured document in which a query expression is embedded, and a first search process according to a search request given from a client. Search means for acquiring a structured document satisfying the search condition indicated by the search request from the document database as a first search result; query expression determination means for determining whether a query expression is embedded in the first search result; When it is determined that a query expression is embedded in the first search result, a query expression executing means for executing a second search process according to the query expression, and the second search by the query expression executing means In the execution result of the process, replace the query expression embedded in the first search result,
A replacement unit that uses the second search result in which the query expression is replaced with the execution result of the second search process as a search result for the search request, and a search request given from the client.
Get information that is included in the query that specifies the query expression to be executed
Query formula designation information acquisition means, and the query formula is embedded in the first search result.
If it is determined that the query expression specifying information is received,
The second search process according to the inquiry formula depending on whether it is acquired by the acquisition means
Query expression execution determination means for determining whether or not to execute, the query expression
Only when it is determined that the second search process should be executed, the execution means executes the second search process.
Perform search processing.

  According to the present invention, when a query expression is embedded in a structured document searched from the structured document database by a search process according to a search request, the query expression is executed, and the execution result (for example, structured data) The query expression embedded in the searched structured document is replaced with the structural part in the document), and the structured document after the replacement is acquired as a search result for the search request. For this reason, the process of searching for multiple structured documents or structure parts in a structured document and creating a new structured document that combines the search results embeds a simple query expression in the original structured document. This makes it possible to perform application processing on the client side without imposing a burden and to improve the efficiency of application development.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a hardware configuration of a client-server system including a structured document search system according to an embodiment of the present invention. The client-server system shown in FIG. 1 mainly includes a database server (database server computer) 10 and a plurality of client terminals (clients). The plurality of client terminals include a client terminal 20. On the client terminal 20, an application (application program) that uses the database server 10 operates. A plurality of client terminals including the client terminal 20 are connected to the database server 10 via a network 30 such as a local area network (LAN). In FIG. 1, client terminals other than the client terminal 20 are omitted.

  The database server 10 is connected to an external storage device 40 such as a hard disk drive. The external storage device 40 stores a database management program 41 and an XML database 42.

  The database management program 41 is used for management of the XML database 42 by the database server 10 and search processing based on a search request (inquiry) using XQuery or the like from the client terminal. The XML database 42 is a structured document database that stores an XML document (XML document data) that is a structured document. The XML database 42 also stores an index created based on the XML document stored in the database 42.

  In the present embodiment, the structured document search system 50 is realized by the database server 10 and the external storage device 40 (the XML database 42 stored in the database server 10).

  FIG. 2 is a block diagram mainly showing a functional configuration of the structured document search system 50 shown in FIG. The structured document search / retrieval system 50 includes a database management system 51 and an XML database 42. The database management system 51 includes a request processing unit 52, a storage processing unit 53, and a search processing unit 54. Each of these processing units 52 to 54 is realized by the database server 10 of FIG. 1 reading and executing the search processing program 41 stored in the external storage device 40. This program 41 can be stored in advance in a computer-readable storage medium and distributed. Further, this program 41 may be downloaded to the database server 10 via the network 30.

  In the XML database 42, an XML document storage unit (structured document storage unit) 421 and an index storage unit 422 are secured. The XML document storage unit 421 is used to store a plurality of XML documents (XML document data). The index storage unit 422 is used to store an index (index) used for searching the XML document stored in the XML document storage unit 421, for example, a structure index file 423 for storing a structure index.

  The request processing unit 52 receives various requests (commands) such as a storage request and a search request given to the structured document search system 50 (internal database management system 51) from the client terminal via the network 30, and receives the request. The type of the request is determined, and either the storage processing unit 53 or the search processing unit 54 is caused to execute the process specified by the request according to the determination result.

  The storage processing unit 53 analyzes the storage request, and stores the XML document designated by the request and the index of the XML document in the XML document storage unit 421 and the index storage unit 422 of the XML database 42, respectively. The storage processing unit 53 includes a database operation unit 530 that operates access to the XML document storage unit 421 and the index storage unit 422 of the XML database 42.

  The search processing unit 54 analyzes the search request and generates a search result that satisfies the search condition (query expression) specified by the search request. The search processing unit 54 generates a database search unit 540, a search unit 541, a query formula execution unit 542, a query formula determination unit 543, a substitution unit 544, a deletion unit 545, an ID acquisition unit 546, and an ID in order to generate this search result. A determination unit 547 is included. The database operation unit 540 operates access to the XML document storage unit 421 and the index storage unit 422 of the XML database 42. The functions of the remaining units 541 to 547 will be described later.

  In the present embodiment, a structure index technique is used as one technique for quickly searching an XML document stored in the XML document storage unit 421 of the XML database 42. In the structure index technology, when an XML document is stored in the XML document storage unit 421 of the XML database 42, information (structure information) indicating the structure of the document is extracted, and the extracted structure is converted into a template (structure template). In this technique, the structure template and the record (position record) indicating the actual position of the structure information in the XML database 42 are associated with each other and indexed by template identification information called a template ID.

  For this reason, in the present embodiment, a structure index is created when an XML document is newly stored in the XML document storage unit 421. The created structure index is stored in the structure index file 423 and stored in the index storage unit 422. The data structure of the structure index file 423 will be described sequentially with two specific examples.

  FIG. 3 shows an example of the XML documents 31 and 32 in the case where two XML documents 31 and 32 having a general structure conventionally known are stored in the XML document storage unit 421 of the XML database 42. Show. The XML document 31 includes <part number> tag, <part name> tag, <description> tag, and <part number> tag as contents (child nodes) of elements (element nodes corresponding to) including <part> tags. , <Component name> tag and element including <description> tag (corresponding element node). The XML document 32 includes two elements (element nodes corresponding to) each including a <part group> tag as contents (child nodes) of elements (element nodes corresponding to the elements) including <stock> tags. The <part group> tag includes an attribute of a part number (@ number). The content of the element including the <part group> tag includes an element including the <stock quantity> tag and an element including the <situation> tag.

  FIG. 4 shows an example of the data structure of the structure index file 423 for storing the structure index created from the XML documents 31 and 32 shown in FIG. The structure index file 423 includes a structure index management unit 424. The structure index management unit 424 includes a structure template management unit 424a and a structure posting area 424b.

  The structure template management unit 424a is a storage unit (structure template storage unit) that stores a set (list) of a pair of a template ID and a structure template indicating a template of the structure of the XML document to which the ID is assigned. In the present embodiment, information representing the structure, for example, information representing the path from the root node to the target node is used for the structure template. For example, the structure template (path) “/ part” indicates a part node that is a child node of the root node. “/” Included in the structure template (path) “/ part” indicates a root node when it is located at the head of the path as in this example.

  On the other hand, the structure posting area 424b has an XML database 42 (in the XML document storage unit 421) of the template ID and the information (data of the structure part in the XML document or XML document) having the same structure as the structure template to which the ID is assigned. ) Is a storage unit (structure template position storage unit) that stores a set (list) of pairs with position information indicating the position. Here, the position information includes a page number and information on the position within the page.

  A unit for storing an XML document in the database 15 is called a page. The example of FIG. 4 shows that the XML documents 31 and 32 of FIG. 2 are stored in the first and second pages, respectively. In the example of the structure posting area 424b in FIG. 4, the position in the page where the structure templates in the XML documents 31 and 32 are stored is assigned in order from the top of the XML document. In practice, however, it need not be assigned in this order.

  By using the structure index management unit 424 including the structure template management unit 424a and the structure posting area 424b, it is only necessary to scan the structure template management unit 424a without accessing the actual XML document. ) Only by the above scan, for example, it becomes possible to perform a search process in accordance with a search request (inquiry request) for designating a structure (structure template) such as “/ part / part number” at high speed. However, just using the structural index management unit 424, that is, using only the structural index, as described in the section “Problems to be solved by the invention”, a plurality of structured documents or structured documents It is difficult to efficiently perform a process of searching for a structure portion and creating a new structured document in which the search results are combined.

  Therefore, in this embodiment, an XML document in which a query expression is embedded is used. FIG. 5 shows an example of an XML document 33 in which a query expression is embedded, which is used in place of the XML document 31 of FIG. The XML document 33 is most different from the XML document 31 in that a query expression (query text) is inserted between an element including a <part name> tag (part name element node) and an element including a <description> tag (description element node). ) 330 is embedded. This query expression 330 is embedded in advance in an XML document 33 that satisfies the conditions specified by the query expression 330 or a location in the XML document 33 in which data of a structure portion in the XML document is to be set. As described above, the structure part in the XML document is also one XML document. Therefore, in the following description, an XML document or a structural part in the XML document is simply expressed as an XML document.

  Query expression 330, that is, <? xquery id = 1 query = // inventory [part group / @ number = 123] / inventory number> indicates “? xquery” to indicate xquery processing. "//" preceding "Inventory" in "// Inventory" indicates an arbitrary position, and "// Inventory" designates an element (inventory element, inventory node) including an <Inventory> tag at an arbitrary position. Therefore, the inquiry formula 330 is “query = // inventory [parts group / @ number = 123”, and “@number (part number)” is selected from elements (inventory nodes) including <inventory> tags at arbitrary positions. This is a search expression that specifies that an element (a stock quantity node) including a tag of the stock quantity of the part “123” (<stock quantity> tag) is to be searched. “Id = 1” will be described in a later-described modification. In the present embodiment, the query expression 330 does not necessarily include “id = 1” information.

  Note that the alphanumeric symbols in the query expression 330 are actually written in single-byte characters. However, in this specification, the alphanumeric symbols in the inquiry formula 330 are expressed by double-byte characters for convenience.

  FIG. 6 shows the structure index included in the structure index file 423 that stores the structure index created from the XML documents 31 and 32 when the XML document 33 of FIG. 5 is used instead of the XML document 31 of FIG. The data structure example of the management part 424 is shown. In FIG. 6, the structure posting area 424b in the structure index management unit 424 is omitted.

  The structure template management unit 424a included in the structure index management unit 424 shown in FIG. 6 is different from the structure template management unit 424a shown in FIG. 4 in that the structure template “/ part /? Xquery” is added. is there. Here, the structure template “/ part /? Xquery” is added (stored) in association with the template ID = 4 in the structure template management unit 424a. In this case, template ID = 4 and (page number, in-page position) = (1) as the template ID and (page number, in-page position) corresponding to the structure template “/ part /? Xquery” in the structure posting area 424b. , 4) are stored.

Next, the XML document search processing in the present embodiment will be described with reference to the flowchart of FIG.
First, it is assumed that a search request for instructing XML document search is sent from the terminal 20 to the structured document search system 50 (database server 10) via the network 30 in accordance with the operation of the client terminal 20 by the user. . The search request from the client terminal 20 is accepted by the request processing unit 52 of the database management system 51 included in the structured document search system 50 (step S1).

  Upon receiving a search request from the client terminal 20, the request processing unit 52 analyzes the request, selects the search processing unit 54 as a functional unit that should process the request, and sends the search request to the search processing unit 54. Pass (step S2). This search request includes a query expression (for example, XQuery).

  When the search processing unit 54 receives a search request from the request processing unit 52, the search unit 541 of the search processing unit 54 is activated. Then, the search unit 541 executes a first search process according to the search request passed from the request processing unit 52 (that is, the search request from the client terminal 20) (step S3). In the first search process, a structure that matches the search condition described in the query expression (first query expression) included in the search request, for example, a path (XPath) “/ part” is specified. A process of acquiring a set of structure indexes for specifying an XML document (XML document data) having a structure from the structure index management unit 424 is performed. Here, “// part” designates an element (part element, part node) including a <part> tag at an arbitrary position, as is clear from the previous example of “// stock”.

  The structure index acquired by the search unit 541 indicates a structure template representing the structure specified by the search condition, a template ID unique to the template, and an actual position of the structure (structure information) in the XML database 42. Position record (page number, position in the page). Here, at least a structure index including a structure template representing “/ part” is acquired.

  If there is an unprocessed structure index in the set of structure indexes acquired by the first search process (step S4), the search unit 541 takes out one unprocessed structure index (step S5). Based on the position record (page number, in-page position) included in the extracted structure index, the search unit 541 specifies the XML document specified by the structure index (step S6). That is, the search unit 541 specifies (searches) an XML document having a structure that matches the search condition described in the query expression included in the search request. Then, the inquiry formula determination unit 543 of the search processing unit 54 is activated.

  The query formula determination unit 543 determines whether a query formula corresponding to the query formula 330 shown in FIG. 5 exists (embedded) in the specified (searched) XML document (first search result). (Step S7). It is possible to confirm where the query expression exists in the specified XML document by referring to the structure index management unit 424.

  If there is a query expression, the query expression execution unit 542 of the search processing unit 54 executes a search process (second search process) according to the query expression (second query expression) (step S8). The replacement unit 544 of the search processing unit 54 is the XML document (the XML document or the structure portion in the XML document) searched in the second search process, that is, the XML document (determined in step S7), which is the execution result of the query expression. The query expression specifying the search processing embedded in the first search result) is replaced, and the replaced XML document (second search result) is used as the search result for the search request (step S9). .

  By the replacement of the query expression of the replacement unit 544, the search unit 541 of the search processing unit 54 searches for the query expression in the XML document that matches the search condition specified in the search request from the client terminal 20 according to the query expression. The new XML document replaced with the XML document (the XML document or the structure portion in the XML document) can be acquired as a search result for the search request.

  When the search unit 541 (search processing unit 54) acquires the search result for the search request by the process based on the structure index extracted in step S5 (steps S6 to S9), the process returns to step S4.

  If the query expression does not exist in the specified XML document (step S7), the search unit 541 (search processing unit 54) acquires the XML document as a search result (step S10), and returns to step S4. .

  In step S4, the search unit 541 determines whether there is an unprocessed structure index in the set of structure indexes acquired by the first search process. If there is an unprocessed structure index, the search unit 541 extracts one unprocessed structure index (step S5) and executes step S6 again.

  On the other hand, if there is no unprocessed structure index, the request processing unit 52 is activated. The storage processing unit 53 returns the search result for the search request from the client terminal 20 acquired by the search processing unit 54 (search unit 541) to the client terminal 20 (step S11).

Next, a specific example of search processing for a search request from the client terminal 20 will be described with reference to FIG.
First, as shown in FIG. 8, the XML document storage unit 421 of the XML database 42 stores an XML document group including the XML document 33 shown in FIG. 5 and the XML document 32 shown in FIG. And The XML document 33 includes a <part> tag, and an element (part node) including the <part> tag includes a query expression 330. The XML document 32 includes a <stock> tag, and an element (stock node) including the <stock> tag includes a <part group tag>. <Part group tag> includes an attribute (attribute node) of a part number (@ number). The attribute name of this attribute is “number (part number)” and the value is “123”.

  When the XML documents 33 and 32 are stored in the XML database 42, the structure index management unit 424 shown in FIG. 6 is created. Assume that the structure index of the XML document that matches the structure specified by “// part” is acquired as a result of the designation of “// part” by the search request from the client terminal 20. In the example of FIG. 8, the XML document that matches the structure specified by “// part” is the XML document 33 including the <part> tag. The XML document 33 is specified as an XML document that matches the search condition specified by the search request from the client terminal 20 by acquiring the structure index including the structure template that matches “/ part” from the structure index management unit 42. (Search) shall be performed.

  A query expression 330 is embedded in the identified XML document 33. In this case, the XML document 33 is not returned as it is as a search result for the search request from the client terminal 20, but the query expression 330 embedded in the XML document 33 is executed as described below. Here, the query expression is stored in the XML document 33 under the “/ part” /? This can be confirmed by searching the structure index management unit 424 for a structure template including a query. Here, the position of the query expression 330 can be confirmed from the position record in the structure index including the structure template “/ part /? Query”.

  When the position of the inquiry formula 330 is confirmed, the inquiry formula 330 is executed. Here, among all the elements (inventory nodes) including the <inventory> tag, the elements including the tag (<inventory number> tag) of the inventory number of the part whose “@ number (part number)” is “123” ( Stock node) is retrieved. The XML document including an element that matches the search condition indicated by the query expression 330 is the XML document 32 in the example of FIG. Here, the information of the inventory quantity node of the part whose “@ number (part number)” in the XML document 32 is “123”, that is, <stock quantity> 100 </ stock quantity> is acquired as the execution result of the query expression 330. Is done.

  Then, as shown in FIG. 8, a new XML document 34 in which the query expression 330 in the XML document 33 is replaced with “<stock quantity> 100 </ stock quantity>” that is the execution result of the query expression 330 is acquired. Is done. This XML document 34 is returned to the client terminal 20 as a search result for the search request from the client terminal 20.

  As described above, in this embodiment, it is predicted that it is necessary to create a new XML document by combining a plurality of XML documents (an XML document or a structure portion in the XML document), for example, an XML document and a structure portion in the XML document. If so, the XML document in which the query expression is embedded is stored in advance in the XML database 42. Then, when an XML document in which an inquiry formula is embedded is searched according to a search request from a client terminal, the inquiry formula is executed. The query expression in the retrieved XML document (first search result) is replaced with the XML document (structure part in the structured document) acquired by executing the query expression, and the query expression is replaced. The XML document (second search result) is acquired as a search result for the search request from the client terminal.

  As a result, in the present embodiment, a process for creating a new XML document by combining a plurality of XML documents (XML document or a structure part in the XML document) is described as a complicated query expression as in the past, or a client terminal Can be executed without complicated processing each time. In the present embodiment, all such processing can be executed on the XML database 42 until the final result is obtained. For this reason, compared with the case where complicated processing is performed each time on the client terminal side, the communication amount (traffic amount) between the client terminal and the structured document search system 50 can be suppressed, and the response time can be shortened.

  In the present embodiment, it is assumed that the query expression embedded in the XML document is a search expression. However, the query formula embedded in the XML document may be an update formula. Here, an example in which an update formula is used as an inquiry formula will be briefly described. First, it is assumed that a node including a value (updated data) to be updated in an XML document in which the update expression is embedded and a node in the XML document including update data are specified by the update expression. . More specifically, the XML document in which the update formula is embedded includes a part node including a stock quantity node, and the value of the stock quantity node is changed to “@ number (part number)” by the update formula. It is assumed that updating to the value of the inventory quantity node included in the inventory node of the part “123” is designated. In this case, the value of the inventory quantity node of the XML document in which the update formula is embedded is, for example, the inventory quantity node of the part whose “@ number (part number)” is “123” in the XML document 32 shown in FIG. Is updated to “100”.

[Modification]
In the above embodiment, when an inquiry expression is embedded in the XML document designated by the structure index acquired by the first search process, the inquiry expression is always executed, and the inquiry expression is determined by the execution result. Replaced. However, even in the case of an XML document in which a query expression is embedded, there is a case where it is desired to acquire an XML document before the query expression is embedded as a search result without executing the query expression.

  Therefore, the feature of the modified example of the above embodiment includes additional information (a kind of XQuery hint information) that specifies a query expression to be executed in the search request, and is specified by a structure index acquired as a search result. Among the XML documents, the query expression is executed only for the XML document in which the query expression specified by the additional information is embedded.

  Next, the XML document search processing in the modification of the above embodiment will be described with reference to the flowcharts of FIGS. 9A and 9B, taking the search of the XML document in which the query expression 330 is embedded as an example, as in the above embodiment. To do. 9A and 9B, the same parts as those in FIG. 7 are denoted by the same reference numerals.

  First, it is assumed that a search request from the client terminal 20 is received by the request processing unit 52 of the database management system 51 included in the structured document search system 50 (step S1). This search request is transferred from the request processing unit 52 to the search processing unit 54 (step S2). It is assumed that this search request includes a query formula (first query formula) to which information (additional information) specifying a query formula to be executed is added. In this modification, a unique ID (inquiry expression designation information) is assigned to the inquiry expression embedded in the XML document. Therefore, the additional information specifies the query expression to be executed by the ID of the query expression.

  The ID acquisition unit (inquiry formula designation information acquisition means) 546 of the search processing unit 54, when additional information is included in the search request, the ID of the query formula to be executed (inquiry formula designation information) from the additional information. Is acquired (step S2a). Then, the search unit 541 of the search processing unit 54 executes a first search process according to the search request (search request from the client terminal 20), and the query expression (first query expression) included in the search request is executed. A set of structure indexes for specifying an XML document having a structure that matches the described search condition (an XML document or a structure portion in the XML document) is acquired (step S3).

  The search unit 541 extracts one unprocessed structure index from the acquired structure index (steps S4 and S5), and specifies the XML document specified by the extracted structure index (step S6). The ID determination unit (query expression execution determination means) 547 of the search processing unit 54 determines that the query expression determination unit 543 determines that the query expression is embedded in the specified XML document (step S7). It is determined whether the query expression should be executed by determining whether the ID of the query expression is included in the set of IDs acquired in step S2a (step S7a).

  If the ID of the query expression embedded in the specified XML document is included in the set of acquired IDs (step S7a), the query expression execution unit 542 of the search processing unit 54 performs the query. The expression is executed (step S8). The replacement unit 544 of the search processing unit 54 is an XML document (an XML document or a structure part in an XML document) searched by executing a query expression, that is, executing a search process (second search process) according to the query expression. The query expression embedded in the identified XML document (first search result) is replaced, and the replaced XML document (second search result) is used as the search result for the search request (step S9). As a result, the search unit 541 (search processing unit 54) searches the XML document in which the query expression is replaced with the XML document (the XML document or the structure portion in the XML document) searched by executing the second search process. As a search result for.

  On the other hand, if the ID of the query expression embedded in the specified XML document is not included in the acquired ID set (step S7a), the query expression execution unit 542 executes the query expression. Is not specified, and execution of the query expression is suppressed. In this case, the deletion unit 545 of the search processing unit 54 deletes the query expression embedded in the specified XML document (first search result), and the deleted XML document (third search result). ) As a search result for the search request (step S7b). Accordingly, the search unit 541 (search processing unit 54) can acquire the XML document from which the query expression is deleted as a search result for the search request.

On the other hand, when the query expression is not embedded in the specified XML document (step S7), step S10 is executed as in the above embodiment.
When step S7b, S9 or S10 is executed, the search unit 541 (search processing unit 54) returns to step S4.

Next, a specific example of search processing for a search request from the client terminal 20 in the present modification will be described with reference to FIG.
First, as shown in FIG. 10, in the XML document storage unit 421 of the XML database 42, an XML document group including the XML document 33 shown in FIG. 5 and the XML document 32 shown in FIG. Is stored. A query expression 330 is embedded in the XML document 33. This inquiry formula 330 includes the ID (id) of the inquiry formula 330. Here, the ID (id) of the query expression 330 is 1.

  Assume that the search request 100 shown in FIG. 10 is given from the client terminal 20 to the structured document search system 50. This search request 100 includes an inquiry formula 101. In this inquiry formula 101, a path (XPath) “// part” is designated by {// part}. Additional information 102 is attached to the inquiry formula 101. The additional information 102 designates execution of an inquiry expression with id (ID) = 1 and an inquiry expression with id (ID) = 2 by (#xquery id = 1, 2 #).

  The query expression 101 “(#xquery id = 1, 2 #) {// part}” to which the additional information 102 is added is embedded in the XML document hit by the query expression “// part”. This is used when it is desired to execute only the query expression with id (ID) 1 or 2 among the query expressions.

  When the query expression 101 to which the additional information 102 is added is given from the client terminal 20 to the structured document search system 50, the search processing unit 54 (search unit 541) has a structure designated by “// part”. The XML document 33 is specified as the matching XML document, that is, the XML document that matches the search condition specified by the search request from the client terminal 20 as in the above embodiment.

  A query expression 330 is embedded in the identified XML document 33. The id (ID) of the query expression 330 is 1, and is included in the set {1, 2} of id (ID) specified by the additional information 102. In this case, the search processing unit 54 (query expression execution unit 542) executes the query expression 330, and information on the inventory quantity node of the part whose “@ number (part number)” in the XML document 32 is “123”, that is, <Stock quantity> 100 </ stock quantity> is acquired as an execution result of the inquiry formula 330.

  As indicated by an arrow 103 in FIG. 10, the search processing unit 54 (search unit 541) indicates that the query expression 330 in the XML document 33 is an execution result of the query expression 330 “<stock quantity> 100 </ stock The new XML document 34 replaced with “number>” is acquired as a search result for the search request from the client terminal 20. The XML document 34 is returned to the client terminal 20 as a search result for the search request from the client terminal 20.

  Next, it is assumed that the search request 110 shown in FIG. 10 is given from the client terminal 20 to the structured document search system 50. This search request 100 includes an inquiry formula 111. This inquiry formula 111 designates a path (XPath) “// part” by {// part} like the inquiry formula 101. Additional information 112 is attached to the inquiry formula 111. The additional information 112 specifies execution of a query expression with id (ID) = 0 by (#xquery id = 0 #).

  When the query expression 111 to which the additional information 112 is added is given from the client terminal 20 to the structured document search system 50, the search processing unit 54 (search unit 541) matches the structure specified by “// part”. The XML document 33 is specified in the same manner as when the query expression 101 to which the additional information 102 is added is given as an XML document.

  A query expression 330 is embedded in the identified XML document 33. The id (ID) of the query expression 330 is 1, and is not included in the set {0} of id (ID) specified by the additional information 112. In this case, the search processing unit 54 does not execute the query expression 330, and the new XML document 35 from which the query expression 330 in the XML document 33 has been deleted, as indicated by the arrow 113 in FIG. As a search result for a search request from.

  As described above, according to the present modification, when a search is performed on an XML document in which a query expression is embedded, a search expression that is to be executed is accepted, thereby performing a more efficient search than the above embodiment. Can do.

  In addition, this invention is not limited to the said embodiment or its modification example as it is, A component can be deform | transformed and embodied in the range which does not deviate from the summary in an implementation stage. For example, in the above-described embodiment or its modification, the XML document has been described as an example of the structured document, but the present invention is not limited to this. The present invention can be similarly applied to structured documents other than XML documents, such as SGML (Standard Generalized Markup Language) documents.

  Further, in the above modification, as a means for designating a query expression to be executed, additional information 102 (112) which is hint information of XQuery is added to the query expression 101 (111) included in the search request from the client terminal 20. Is added. However, a parameter or the like different from the XQuery hint information may be used and passed from the client terminal 20 to the structured document search system 50 independently of the query expression 101 (111).

  In the above embodiment or its modification, the client terminal 20 is connected to the database server 10 of the structured document search system 50 via the network 30. However, the client terminal 20 may be directly connected to the database server 10 of the structured document search system 50. Further, by adopting a configuration in which an application similar to that operating on the client terminal 20 operates on the database server 10, even if the keyboard, display, etc. of the database server 10 are used like the client terminal 20, that is, The database server 10 may also be used as a client terminal.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment or the modification thereof. For example, you may delete some components from all the components shown by embodiment or its modification.

1 is a block diagram showing a hardware configuration of a client-server system including a structured document search system according to an embodiment of the present invention. FIG. 2 is a block diagram mainly showing a functional configuration of the structured document search system shown in FIG. 1. The figure which shows the example of two XML documents of the general structure known conventionally. The figure which shows an example of the structure index file shown by FIG. The figure which shows an example of the XML document with which the inquiry type | formula was embedded. An example of the data structure of the structure index management unit created from two XML documents including the XML document in which the query expression is embedded is shown. 6 is an exemplary flowchart showing the procedure of an XML document search process in the embodiment. The figure for demonstrating the specific example of the search process in the embodiment. 6 is an exemplary flowchart illustrating the procedure of an XML document search process according to a modification of the embodiment. 6 is an exemplary flowchart illustrating the procedure of an XML document search process according to a modification of the embodiment. The figure for demonstrating the specific example of the search process in the modification of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Database server, 20 ... Client terminal, 30 ... Network, 31-35 ... XML document, 40 ... External storage device, 41 ... Database management program, 42 ... XML database, 50 ... Structured document search system, 51 ... Database management System 52... Request processing unit 53. Storage processing unit 54. Search processing unit 101, 111, 330 ... Query expression 421 ... XML document storage unit 422 ... Index storage unit 423 ... Structure index file 424 ... Structural index management unit, 424a ... structural template management unit, 424b ... structural posting area, 541 ... search unit, 542 ... query formula execution unit, 543 ... query formula determination unit, 544 ... substitution unit, 545 ... deletion unit, 546 ... ID Acquisition unit (inquiry type designation information acquisition means), 5 7 ... ID determination unit (query expression execution determination means).

Claims (2)

A structured document database for storing a plurality of structured documents including a structured document in which a query expression is embedded;
Search means for acquiring, as a first search result, a structured document that satisfies a search condition indicated by the search request from the structured document database by a first search process in accordance with a search request given by a client;
Query formula determination means for determining whether a query formula is embedded in the first search result;
When it is determined that a query formula is embedded in the first search result, query formula execution means for executing a second search process according to the query formula;
The query expression embedded in the first search result is replaced with the execution result of the second search process by the query expression executing means, and the query expression is replaced with the execution result of the second search process. Replacement means for using the second search result obtained as a search result for the search request ;
A information included in the search in the request given from the client, the query expression specified information acquiring means for acquiring information specifying a query expression to be executed,
When it is determined that the query expression is embedded in the first search result, the first information according to the query expression is determined depending on whether the information specifying the query expression is acquired by the query expression specifying information acquisition unit. ; and a query expression execution determining means for determining whether to second search processing is executed,
The structured document search system, wherein the query expression execution unit executes the second search process only when it is determined that the second search process should be executed. In a database server computer that manages a structured document database that stores a plurality of structured documents,
Obtaining a structured document satisfying a search condition indicated by the search request from the structured document database as a first search result by a first search process according to a search request given from a client;
Determining whether a query expression is embedded in the first search result;
If it is determined that a query expression is embedded in the first search result, executing a second search process according to the query expression;
A second search in which the query expression embedded in the first search result is replaced with the execution result of the second search process, and the query expression is replaced with the execution result of the second search process. A result as a search result for the search request ;
Information contained in the search request given by the client, which should be executed.
Obtaining information specifying a query expression;
If it is determined that a query expression is embedded in the first search result, the query
Depending on whether or not the information specifying the formula is acquired,
Determining whether a search process should be performed;
Only when it is determined that the second search process should be executed, the second search process is performed.
A database management program for executing the steps to be executed.

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