JPH09218876A - Node link searching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a node link searching device capable of limiting the search of unrequired nodes having no semantic connection. SOLUTION: The number of the nodes from the node to be an origin to the node of a search destination is turned to a hierarchy number and the limiting conditions of a search range are set by the maximum value of the hierarchy number. A file collecting part 21 traces a link from the node to be the origin, successively reads the nodes from a server machine 13, obtains the title of the link destination node, a storage position and the correspondence relation of a link origin and a link destination from the nodes and registers them. A hierarchy calculation part 27 obtains the hiearchy number of the link destination node of the node every time the node is read from the server machine 13. When the hierarchy number becomes more than the set maximum value, the tracing of the further link and the read of the nodes are stopped. Since the search range is limited by the hierarchy number from the origin, only the nodes with the semantic connection with the node of the origin are searched in a required range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a node / link search device for finding a range of nodes to be searched under a specified condition in a database of nodes and links, and more particularly to a distributed hypermedia system. The present invention relates to a node / link search device used in a database in which nodes are distributed and stored in a plurality of servers on the network.

[0002]

2. Description of the Related Art As one of databases, there is a hypertext system in which a plurality of nodes storing various kinds of information such as document files are searched by following links representing their subordinate relationships. Such a hypertext search operation can be smoothly performed by preliminarily retaining the index of information stored in the node and the link relation between the nodes.

Japanese Unexamined Patent Publication No. 4-321144 discloses a hypertext system that can be displayed so that the relationships between nodes can be easily grasped. Since each node can be linked to any node, a link may be formed in a loop between a plurality of nodes.
In this system, a display screen is created based on a table in which link relationships between nodes are registered in advance. Then, the looped links are separated, and when a certain node is set as a starting point, the link relationship between the nodes is displayed as a tree structure.

Conventionally, a hypertext system has been built in a local workstation or the like, but with the recent development of communication technology, a system in which nodes are distributed and stored in a plurality of servers connected via a network has appeared. doing. Such a system is called a distributed hypermedia system. For example, the World Wide Web (hereinafter referred to as WWW) is drawing attention as a means of transmitting information on the Internet. Hypermedia is hypertext that can handle not only text data such as characters and tables but also multimedia data such as video and audio.

In the distributed hypermedia system, a table showing a link relationship between nodes is created by acquiring information on nodes stored in each server via a network. Information representing the link relationship between nodes will be referred to as a node / link information database. A device that creates the node / link information database will be referred to as a node / link search device.

[0006] In the World Wide Web (WWW), nodes are distributed among a plurality of server machines on the Internet, and the data of the nodes accumulated in each server is a hypertext transfer protocol (HyperText). Transfer Protocol (hereinafter referred to as HTTP)). The multimedia documents that are nodes are HyperText Markup Languages.
p Language Hereinafter referred to as HTML. ) Is described in a hypermedia description language format.

The node / link search device analyzes the content of the node described in HTML acquired via the network and extracts a hyperlink indicating the storage location of the next link destination node. Hyperlink is HT
By searching for a predetermined character string (this is called a tag) indicating the start position and a tag indicating the end position defined by the ML, a character string between them is extracted.

A hyperlink representing a destination node is a uniform resource locator (Uniform R
esource Locators Referred to as URL below. ) Is used for description. The node and the hyperlink can be searched by finding the part sandwiched between the tags indicating the hyperlinks in the acquired text of the node and extracting the character string described by the URL from the part. The node / link search device builds a node / link information database by repeating such a search. "WWW Wanderer", "WWW Robot", "WWW Spide"
There is something called "r".

The hyperlink representing the linked node has the following structure defined in the URL. <Scheme>: <Scheme-Spec
ific-Part> In the case of the Hypertext Transfer Protocol (HTTP) scheme used as a transfer protocol of a document file of a node in the World Wide Web (WWW), the hyperlink is represented as follows. http: // <host>: <port>: <path>? <searchpart>

Here, "<host>" represents the host name of the server machine in which the document file exists, and "<port>" represents the port number for communication. The port number can be omitted. If omitted, the standard value "80" is treated as specified. "<Path>" represents the location of the document file on the server machine. "<Searchpart>" is an area used when data is passed to the server machine.

FIG. 14 shows an example of nodes and hyperlinks connecting these nodes. The document files included in the node 1001, the node 1002, and the node 1003 are described in HTML. The contents of the document file are categorized and identifiable by various tags. Of these, the tag that indicates a hyperlink is <A HREF="URL">… </
It is represented by A>, and the part corresponding to "URL" indicates the link destination node. In the document file of the node 1001, areas 1004 and 1005 surrounded by dotted lines respectively represent hyperlinks.

The node 1001 has a URL of "http: // hos
It is assumed that the node is represented as “tA / tale / TOC.html.” The node 1002 is “http: // hostB: 80 / tale.
/Introduction.html "and the node 1003 is" http: // h
It is assumed that the node is represented as “ostC: 8080 / tale / Birth.html”. Hyperlink 10 in the node 1001
Reference numeral 04 indicates the node 1002. The hyperlink 1005 in the node 1001 is the node 100
3 is indicated. By the hyperlink registered in the node document file like this,
The linked node is represented.

FIG. 15 shows an example of the relationship between the documents of the nodes. The area enclosed by the dashed line represents the server in which the node is stored. Area 1011 is a server machine with a host name "A", area 1012 is a server machine with a host name "B", area 1
013 represents each server machine whose host name is "C".

Nodes 1001 to 1003 shown in FIG.
Content of the document file included in the above, which is obtained by removing tags specified by HTML etc. 1014 to 1016
Is an area 101 representing the server storing the node
Represented within 1-1013. Also, hyperlinks 1017 and 1018 represent that the link destination nodes of the node 1001 are the node 1002 and the node 1003.

Next, the configuration of the node / link search device for constructing the node / link information database based on the hyperlinks registered in each node will be described.

FIG. 16 shows an outline of the configuration of a conventionally used node / link search device.
A plurality of server machines 1023 are connected to the node / link search device 1021 via a network 1022 such as the Internet. Each server machine 1023
The node that stores the document file is stored in. The node / link search device 1021 includes a file collection unit 1031 that collects node files from the server machine 1023, and a hyperlink extraction unit 1032 that extracts hyperlinks from the node files acquired from the server machine 1023. .

Further, it has a node / link information database 1033 for accumulating / managing various attribute information such as storage destinations of nodes and link information between nodes based on the extracted hyperlinks. The search range control unit 1034
This is a part that limits the search range of the node to a range that matches the conditions of the search range given from an input terminal (not shown) or an external file for setting. System control unit 1035
Is a circuit part that integrally controls the flow of operation of each part in the node / link search device 1021.

The hyperlink extraction unit 1032 includes a hypermedia description language analysis unit 1036 that analyzes the contents of the multimedia document file of the node written in the hypermedia description language. The hypermedia description language analysis unit 1036 is adapted to extract hyperlinks and link destination nodes by detecting various tags. The search range is the server machine 10
It is designated by the host name as an identifier of 23. The search range control unit 1034 includes a host name comparison unit 1037 that compares the host name of the server machine of the storage destination of the node with the host name as the specified search range. By comparing the host name as a part of the information indicating the storage position of the node, it is determined whether or not the node is within the search range.

The file collection unit 1031 of the node / link search device 1021 operates from the server machine 1023 that matches the host name specified as the search range to the network 1
Read the multimedia document file of the node through 022. Then, the hyperlink extraction unit 10
Information of the hyperlink and the link destination node is extracted from the file read by 32. Search range control unit 103
When the host name of the server machine storing the extracted link destination node is within the search range, 4 continues the search for the link destination node. On the other hand, when the server machine of the storage destination of the link destination node is out of the search range, the search to the nodes beyond that is stopped. Various attributes of nodes and hyperlinks within the search range are registered in the node / link information database 1033.

As described above, in addition to the one that specifies the host name as the search range, the node that cannot specify the search range at all
There is also a link search device.

[0021]

A node / link search device in which a search range cannot be specified searches the entire network such as the Internet and searches all nodes existing in all server machines on the network. . Therefore, in the node / link information database, unnecessary information about a node other than the one that should originally be the search range is accumulated, which not only wastes its resources but also reduces the work efficiency in searching. . further,
There is also a problem that it takes a long time to access the server machine or the network where the node exists, and the use of network resources of other users is restricted.

Even a device that can specify a search range can only limit the search range by host name. This means that the search range is limited by the physical position of the node. However, since hypertext is searched sequentially based on the semantic relationship between nodes, it is not possible to specify an appropriate range by specifying the search range in units of server machines.

For example, in the example shown in FIG. 15, the registered node 1014 of the table of contents exists on the server "A" 1011 and the server "B" 1012 and the server "C" 1 exist.
Nodes 1015 and 1016 in which sentences having contents corresponding to the table of contents are registered are respectively registered on 013. In this case, if it is desired to set not only the table of contents but also the contents of the written document as the search range, the server "A",
All of the servers "B" and "C" must be specified as the host names in the search range. As a result, a large number of other nodes that have no meaning connection with the table of contents existing on the server “B” and the server “C” are included in the search range, and unnecessary nodes are searched. .

Therefore, an object of the present invention is to provide a node / link search device capable of limiting the search for unnecessary nodes that are not semantically connected.

[0025]

According to a first aspect of the present invention, any one of the hypertext nodes can be arbitrarily selected based on link information indicating the name of the link destination node and the storage location of the link destination node. Set the limit condition of the search range when sequentially performing the search from the node to the link destination node as the maximum value of the number of layers, which is the number of nodes existing from the search origin node to the search destination node The search condition setting means, the file collecting means for repeatedly reading the contents of the link destination node indicated by the link information from the server storing the same, in order from the node serving as the starting point of the search, and the file collecting means. Each time the contents of one node are read, the link information contained in that node and the link destination node indicated by this will be associated with the node read this time. A node / link information storage means for storing the information to be passed, and a layer number calculation means for obtaining the layer number of the link destination node indicated by the link information included in the node each time the file collecting means reads the content of the node. , When the number of layers obtained by the number-of-hierarchies calculating means is larger than the maximum value of the number of layers set by the search condition setting means, the reading of the contents of the nodes linked after the node read this time by the file collecting means is stopped. The node / link search device is provided with a search range limiting means.

That is, according to the first aspect of the invention, the number of nodes existing between the node that is the starting point of the search and the node that is the search destination is the number of layers, and the condition for limiting the search range is the maximum number of layers. Specify by value. The contents of the nodes are sequentially read from the server by tracing the links from the node serving as the starting point, and the names and storage positions of the nodes linked to the read nodes and the correspondence relationship between the link source nodes and the link destination nodes are registered. Also, every time a node is read from the server, the number of layers of the node to which the read node is linked is obtained. When the number of layers exceeds the set maximum value, the link is followed further and the reading of the node is stopped.

As a result, the range of search is limited by the number of layers from the node serving as the starting point. In this way, since the search range is limited by the number of layers from the starting node, the searched nodes are only those having a strong semantic connection with the starting node. Further, since the search range can be limited by the number of layers, it is possible to collect only the information within the required range.

According to the second aspect of the invention, based on the link information indicating the name of the link destination node and the storage position of the link destination node included in each node of the hypertext, the link destination from any node is A search condition setting means for setting a search range limiting condition when sequentially searching nodes as the maximum value of the number of layers, which is the number of links existing from the node that is the starting point of the search to the node of the search destination. ,
File collection means for repeatedly reading the content of the link destination node indicated by the link information from the server that stores it, starting from the node that is the starting point of the search, and each time the content of one node is read by this file collection means In the node / link information storage means for storing the link information included in the node and the information indicating the correspondence between the node of the link destination indicated by this node and the node read this time, and the content of one node is read by the file collection means. For each layer, the layer number calculation means for obtaining the layer number of the link to the link destination node represented by the link information included in the node, and the layer number obtained by this layer number calculation means are equal to the layer number set by the search condition setting means. If it is larger than the maximum value, the contents of the nodes linked after the node read this time are displayed. And it is provided in the node link search apparatus and a search range limiting means for stopping the reading by yl collection means.

That is, according to the second aspect of the present invention, the number of links existing between the node that is the starting point of the search and the node that is the search destination is the number of layers, and the range in which the search is performed is limited by the maximum value of the number of layers. ing. As a result, it is possible to collect only the information about the node that has a strong semantic connection with the starting node. In addition, the names, storage positions, and link relationships between nodes can be collected only for nodes within the search range specified by the number of layers.

According to the third aspect of the invention, the nodes to be searched are distributed and stored in a plurality of servers connected to the network.

That is, in the invention according to claim 3, the nodes to be searched are distributed and stored in a plurality of servers connected via the network. Since the search range is limited by the number of layers, only the necessary node information can be collected from a large number of servers even if the nodes are distributed among a plurality of servers. For example, if the search range can be specified only on a server-by-server basis, not only will the number of layers exceed the required number of layers from the starting node,
In some cases, even unrelated nodes that have no link relationship with the starting node are collected. By limiting the search range by the number of layers, even if the search range nodes are distributed to multiple servers, it is possible to collect only the information about the necessary range nodes that are semantically connected from the starting node. it can.

In the invention according to claim 4, the file collecting means determines whether the node of the link destination indicated by the link information included in the node read this time is the same as the already read node or not. The discriminating means and the multiple reading suspending means for suspending the re-reading of the node when it is discriminated by the same node discriminating means that the node is the same as the node already read.

That is, in the invention according to claim 4, the node which has been read once is prevented from being read again. This makes it possible to avoid repeatedly searching the looped range.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a node according to an embodiment of the present invention.
1 is a diagram showing an outline of the configuration of a link search device. The search procedure on the hypermedia structure can be regarded as a tree structure whose root is the node that started the search. Therefore, with the root as the starting point, the depth of a tree with each node is set as the number of layers, and the search range is limited by the number of layers from the starting point.

A plurality of server machines 13 that store nodes are connected to the node / link search device 11 via a network 12 such as the Internet. The node / link search apparatus 11 includes a file collection unit 21 that collects node files from the server machine 13 and a hyperlink extraction unit 22 that extracts hyperlinks and link destination nodes from the node files acquired from the server machine 13. Is equipped with.

Further, the node / link search device 11 has a node / link information database 23 for accumulating and managing the extracted hyperlinks and various attribute information of the link destination nodes. The search range control unit 24 is a part that limits the search range of the node so as to match the condition for specifying the search range input from an input terminal (not shown) or a setting file. The system control unit 25 is a circuit unit that integrally controls the operation flow of each unit in the node / link search device 11.

The hyperlink extraction unit 22 includes a hypermedia description language analysis unit 26 that analyzes the contents of the multimedia document file of the node written in the hypermedia description language. The hypermedia description language analysis unit 26 is adapted to extract hyperlinks and link destination nodes by detecting various tags. The hyperlink extraction unit 22 also includes a layer number calculation unit 27 that calculates the number of layers of the extracted link destination node. The number-of-layers calculation unit 27 obtains the number of layers of the link source node plus “1” as the number of layers of the link destination node.

The search range is specified by the host name as the identifier of the server machine 13 and the maximum number of layers. The search range control unit 24 compares the host name of the storage destination of the node with the host name specified as the search range, and the number of layers of the node and the maximum number of layers as the limit value of the search range. A hierarchy number comparison unit 29 for comparing and is provided. The search range control unit 24 limits the search range depending on the number of layers of nodes and the host name of the storage destination. In addition, in order to prevent multiple reading of the same node, the range of search is also limited by the elapsed time from the previous search.

The file collection unit 21 is connected to the network 12
The multimedia document file of the node is read from the server machine 13 through. The hyperlink extraction unit 22 extracts a hyperlink and a link destination node from the multimedia document file based on the analysis result of the hypermedia description language analysis unit 26. Next, the layer number calculation unit 27 calculates the number of layers of the link destination node or the hyperlink by adding "1" to the link source node.

The search range control unit 24 determines the search range based on whether the number of layers of nodes or hyperlinks is less than or equal to the specified maximum number of layers, or whether the host name partially matches the specified one. Restrict. For the nodes and hyperlinks within the search range, their attribute information is stored in the node / link information database 23. A table for registering attributes of nodes in the node / link information database 23 is called a node table, and a table for registering attributes of links is called a link table. In this way, by limiting the search range according to the number of layers, it is possible to prevent collection of attribute information about unnecessary nodes and registration in the database.

FIG. 2 shows an example of registered contents of the node table. In the node table 31, from the left of the figure, a node identifier 32, a scheme (Scheme) 33, a host name 34, a port number 35, and a scheme-specific part (Scheme-
Specific) 36, number of layers 37, registration date / time 38, search date / time 39, and last update date / time 41 are registered. Of these, the node identifier 32 is an identifier automatically generated when the attribute information of the node is registered in the node table by the database management system (DBMS) not shown in FIG. The scheme 33, the host name 34, the port number 35, and the scheme specific part 36 correspond to each part of the character string of the URL indicating the storage position of the node. The number of layers 37 is an item representing the number of layers of nodes from the search start position.

The registration date and time 38 indicates the date and time when the node was first registered in the database. The search date and time 39 represents the latest date and time when this node was searched. The last update date and time 41 represents the last update date and time of the multimedia document file of the node. In the figure, the items of the search date / time 39 and the last update date / time 41 enclosed by a dotted line 42 are attributes that are updated when registered as a link source node, and the items enclosed by a dotted line 43 are of the link source node. This is an attribute that is updated when registered as a link destination node pointed to by a hyperlink.

FIG. 3 shows an example of registered contents of the link table. The link table 51 includes a link identifier 52, a link source node identifier 53, and
The link destination node identifier 54 is registered. The identification numbers of the nodes automatically assigned by the DBMS are registered in these items. The node identifier of the source node of the hyperlink indicated by the link identifier 52 is registered as the link source node identifier 53, and the node identifier of the node pointed to by the hyperlink is registered as the link destination node identifier 54.

In the node / table 31 of the node / link information database, at least one piece of information about the node serving as the search starting point is registered in advance. At this time, items to be registered are the node identifier 32, the scheme 33, the host name 34, the port number 35, the scheme specific part 36, the number of layers 37, and the registration date and time 38. “0” is set in advance for the number of layers of the node that is the starting point of the search.

FIG. 4 shows the flow of operations performed by the node / link search device. The processing of the steps surrounded by the one-dot broken line 61 is performed by the system control unit 25 of the node / link device. The processing of the step surrounded by the dashed line 62 is performed by the search range control unit 24, and the processing of the step surrounded by the dashed line 63 is performed by the file collection unit 21 and the hyperlink extraction unit 22. First, prior to the search, the system control unit initializes the system such as inputting search conditions (step S101). The search condition is input from an input terminal or an external file not shown in FIG. As the search conditions, here, the maximum value of the number of layers of the nodes that should be the search range (maximum number of layers), the elapsed time for determining the previous search result as old, and the server machine to be searched are specified. A character string (part or all of the host name to be searched) is set as a condition.

The system control unit 25 uses the node table 3
1 is searched to check whether or not there is an unsearched node (step S102). If the search date / time 39 registered in the node table 31 is undefined (unregistered),
When any of the cases where the search date and time 39 is a time past the elapsed time set as the search condition with respect to the current time, the node is determined as an unsearched node. When there is an unsearched node (step S102; Y), the search range control unit 24 retrieves the attribute information of one unsearched node from the node table 31. At this time, the node having a smaller number of layers is preferentially selected (step S103). Therefore, initially, the attribute information of the node at the search start point having the number of layers “0” is extracted.

Next, it is determined whether or not the selected node is a node existing within the designated search range (step S104). The process of determining whether it is within the search range will be described in detail later. When the node is within the search range (step S104; Y), the table file is updated by reading the document file of the node through the network and additionally registering the link destination node described in the node file in the node table. The process (step S105) is performed. Details of the table update process will be described later. After the update process (step S105) for one node is completed, the process is repeated in step S10.
Returning to step 2, the search process for unsearched nodes is repeated.

If the selected node is outside the designated search range (step S104; N), the search time 39 for the selected node in the node table 31 is changed to the current time (step S106). , And returns to step S102. When the unsearched node no longer exists in the node table (step S102; N), the ending process for ending the search is performed (step S10).
7), the process ends (end).

FIG. 5 shows the flow of processing for determining whether or not the node is within the search range. Here, whether or not it is within the search range is determined only by the number of layers. First, the search range control unit 24 compares the number of layers of the selected node with the maximum number of layers set as the search condition (step S201). If the number of layers of nodes is larger than the maximum number of layers (step S20)
1; N), it is determined that this node does not exist in the search range (step S202). If the number of layers of nodes is smaller than or equal to the maximum number of layers (step S
201; Y), and it is determined that this node exists in the search range (step S203).

FIG. 6 shows the flow of another example of the processing for determining whether or not the node exists within the search range. Here, in addition to the determination based on the number of layers, the determination based on the host name is added. The search range control unit 24 compares the number of layers of the selected node with the maximum number of layers (step S301). If the number of layers of the node is larger than the maximum number of layers (step S301; N), this node is It is determined that it does not exist in the search range (step S30
2). If the number of layers of the node is smaller than or equal to the maximum number of layers (step S301; Y), it is checked whether the character string specified as the host name of the search range partially matches the host name of the node. (Step S30
3).

For example, when "AB" is specified as the search character string, all the characters including the character string "AB" specified from the beginning of the host name such as "ABC" and "ABD" are partially matched. To be determined. If there is no partial match such as "CAB" (step S30)
3; N), it is determined that this node does not exist in the search range (step S302). When they partially match (step S303; Y), it is determined that this node exists in the search range (step S304). Here, the number of layers is determined, and then the partial matching of host names is determined, but the order may be changed.

FIG. 7 shows the flow of the table updating process shown in FIG. This processing is performed by the file collection unit 21 and the hyperlink extraction unit 22. First, the content of the node determined to exist within the search range in step S104 of FIG. 4 is read out from the server machine storing it through the network. Therefore, the file collection unit 21 reads the attribute information of the corresponding node from the node table 31 of the node / link information database 23 (step S401).
Here, it is assumed that the number of read node hierarchies is n.
Next, the file collection unit 21 initializes a communication buffer and a temporary buffer (not shown) used for communication with the server machine, and then connects to the server machine 13 to prepare for transfer (reading) of the document file of the node. (Step S402).

Subsequently, the file collection unit 21 starts the transfer of the document file according to the transfer protocol of the distributed hypermedia system. File collection unit 21
Reads the transfer protocol message header section (step S403) and checks the format such as the description language of the document file (step S404). If the read file is not in the hypermedia description language format (step S404; N), the end of the document file is read (step S405). Then, post-processing such as releasing the communication buffer and the temporary buffer and disconnecting the connection with the server machine is performed (step S406), and the processing ends (end).

When the read file is in the hypermedia description language format (step S404; Y), the file collecting unit 21 reads the document file of the transfer protocol message body into the communication buffer (step S407). Next, the hypermedia description language analysis unit 26 moves the start character to the end character of the tag representing the hyperlink portion to the temporary buffer (step S408). The part describing the link destination node is extracted from the hyperlinks stored in the temporary buffer (step S409). The layer number calculation unit adds “1” to the layer number “n” of the link source node, “n +
1 "is obtained as the number of layers of the link destination node (step S410).

The attribute information of nodes and hyperlinks thus obtained is stored in the node / link information database 23.
The data is written in the node table 31 and the link table 51 (step S411). At this time, partial items of the attribute information of the link source node and the attribute information of the link destination node, and all items of the hyperlink attribute information (link table) are written. As a result, the attribute information about the advanced link destination node linked to the node read this time and the hyperlink from the read node to the link destination node are additionally registered in each table. Become. However, if the same node has already been registered, no additional registration in the table is performed and only the search date and time is updated. This avoids multiple registration of the same node or hyperlink.

Next, it is checked whether or not processing has been performed up to the end of the document file of the node read this time (step S412). If the end has not been reached (step S4).
412; N), and returns to step S407. Each node is
Since there may be a plurality of link destination nodes, by repeating such processing until the end of the file, all the link destination nodes of the node read this time are registered in the node table and the link table.
When processing is performed up to the end of the file (step S41
2; Y), the table update process for this node ends (END).

The contents of the attribute information registered in the node table and the link table in step S411 of FIG. 7 will be described. The node read from the server machine is the link source node, and the node described in the hyperlink included in this node is the link destination node. First, regarding the link source node, the search date and time 39
Then, the last update date / time 41 is registered. Thereby, the latest time information of when the node is searched can be left. For example, in the node table 31 shown in FIG. 2, it is assumed that the node having the node identifier “1” is read from the server machine and the node having the node identifier “2” is described as the destination pointed to by the hyperlink.
In this case, the node with the node identifier “1” is the link source node, and the node with the node identifier “2” is the link destination node.

The search date and time and the last update date and time enclosed by the dotted line 42 in FIG. 2 are updated as the attribute information of the link source node. The portion enclosed by the dotted line 44 in FIG. 2 is registered as the attribute information of the link destination node. That is, the node identifier and the URL indicating the storage location of the node
The scheme, the host name, the port number, the scheme specific part, the number of layers calculated by the number of layers calculating part, and the registration date and time corresponding to the character string of are registered in the database. As the node identifier, the one automatically generated by the DBMS is registered. Regarding the link destination node, since the hyperlink included in it has not been actually read from the server machine 13 yet, the search date and time and the last update date and time remain unregistered.

In the link table 51, a link identifier 52 automatically generated by the DBMS, a link source node identifier 53, and a link destination node identifier 54 are registered. An example will be described with reference to FIG. It is assumed that the node having the node identifier of "1" is read and the node having the node identifier of "2" is the link destination node by the hyperlink. First, since the node identifier of the source node of the hyperlink (55) whose link identifier is "1" is "1", this value is registered as the link source node identifier (56). Also, since the node identifier of the node pointed to by the hyperlink is "2", this value is registered as the link destination node identifier (57). If other hyperlinks of the read node are registered, link identifiers are also assigned to those links, and the link source node identifier and the link destination node identifier are registered. When there are two hyperlinks, the dotted line 58 in FIG.
Information in the range indicated by is registered in the link table 51.

The node table 31 and the link table 51 are updated each time one node is read from the server machine 13 and a new link destination is found. Therefore, when the table updating process (step S105) is completed for one node in the flowchart of FIG. 4 and the process returns to step S102, the node newly registered in the table updating process also becomes the search target. As a result, the search for link destinations proceeds one after another. However, the search range is limited by conditions such as the number of layers.

Further, the unsearched determination criterion is that the searched date and time is undefined or a time that is past the elapsed time or more. Further, the searched date and time of the node once searched is registered with the time close to the current time. Link destinations will not be surveyed repeatedly for nodes. As a result, for example, even if the link destination of the node “A” is the node “B” and the destination destination of the node “B” is the node “A”, a loop is formed by the links. ”
There is no need to re-examine and repeat the loop up to the maximum number of layers.

Since the search range is limited by the number of layers of nodes in this way, only the node having a strong semantic connection with the starting node can be searched. In addition, unnecessary searches can be reduced as compared with the case where the search range can be limited only on a server basis.

Modification

In the embodiments described so far, the number of layers is given as the attribute information of the node, but in the modification, it is determined whether or not it is within the search range based on the number of layers of the hyperlink. There is. The configuration of the device is the same as that shown in FIG. 1 and its explanation is omitted.

FIG. 8 shows an example of the registered contents of the node table used in the modified node / link search device. The same items as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be appropriately omitted. The node table 71 differs from the node table 31 shown in FIG. 2 in that items for registering the number of layers and the search date and time are deleted.

FIG. 9 shows an example of the registered contents of the link table used in the node / link search device of the modified example. The same items as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be appropriately omitted. Link table 81
In addition to the link table 51 shown in FIG. 3, it includes an item 82 for the number of layers and an item 83 for the search date and time. These are registered in the node table in the embodiment. In the modified example, it is necessary to register at least one hyperlink to be the starting point of the search in the link table 81 before the search. The hyperlink that is the search start point registered here is a virtual one, and the link source node does not exist (unknown). Also, the attribute information about the link destination node indicated by the hyperlink that is the search start point must be registered in advance in the node table 71.

As the contents to be registered in the node table 71 prior to the search, there is the node identifier of the link destination node indicated by the hyperlink of the search starting point. This value is DB
Assigned automatically by MS. Furthermore, a scheme, a host name, a port number, and a scheme-specific part are initially registered as items corresponding to the URL character string indicating the storage location of the node. Also, the registration date and time indicating the time when this node is registered in the database is initially registered. In the example of FIG. 8, items in the range surrounded by the dotted line 72 are initially registered.

The contents initially registered in the link table 81 include a link identifier which is the identifier of the hyperlink that is the starting point of the search. This value is automatically generated by the DBMS. Since the link source of the hyperlink that is the starting point of the search is unknown, the initial value of the link source node identifier is set to "0" indicating undefined. As the link destination node identifier, the same value as the node identifier assigned by the DBMS is registered for the link destination node. As the number of layers, "0" which is the starting point of the search is initially registered. The search date and time is to register the date and time when the search for the hyperlink was performed, and is left undefined as the initial value for starting the search. In the example of FIG. 9, items enclosed by a dotted line 84 are initially registered.

FIG. 10 shows the flow of processing performed by the node / link search device in the modification. The steps surrounded by the dashed line 101 are the system control unit 25.
Represents the processing performed by. The steps surrounded by the dashed-dotted line 102 are controlled by the search range control unit 24 by the dashed-dotted line 10
The steps surrounded by 3 represent the processes performed by the file collection unit 21 and the hyperlink extraction unit 22.

First, the system control unit 25 initializes the system (step S501). At this time, the maximum number of hierarchies as the maximum number of hierarchies of the search range and the elapsed time serving as a reference for treating the previous search result as old are set. When setting the server range by host name, enter a character string to limit the host name. These are taken in from an input terminal (not shown) or an external file. Next, it is checked whether or not there is a hyperlink that has not been searched in the link table 81 (step S502). The unsearched hyperlinks have undefined (unregistered) search date / time or have a search date / time older than the current time by an elapsed time or more.

When a hyperlink that has not been searched exists in the link table 81 (step S502;
Y), one of the unsearched hyperlinks is selected and its attribute information is taken out (step S503).
Next, the search range control unit 24 determines whether or not one selected hyperlink is within the search range (step S504). It is determined by the number of layers or both the number of layers and the host name, the details of which will be described later.

If it exists within the search range (step S504; Y), the table updating process (step S50) is performed.
Perform 5). In this processing, the attribute information of the link destination node indicated by the hyperlink is taken out from the node table 71, the document file of this node is read from the server machine, and the attribute information of the link destination node registered in this is additionally registered. . The detailed flow of processing will be described later. After the table updating process (step S505) for the link destination node indicated by the hyperlink is completed, the process returns to step S502 again, and the search process for the unsearched hyperlink is repeated.

If the selected hyperlink is outside the search range (step S504; N), the link table 81
The search date / time 39 for the selected hyperlink is changed to the current time (step S506), and step S5
Return to 02. When an unsearched hyperlink no longer exists in the link table 81 (step S502;
N), an end process for ending the search is performed (step S507), and the process ends (end).

FIG. 11 shows the flow of processing for determining whether or not the hyperlink is within the search range.
Here, whether or not it is within the search range is determined only by the number of layers of the hyperlink. First, the search range control unit 24
Compares the number of layers of the selected hyperlink with the maximum number of layers set as the search condition (step S6).
01). When the number of layers of the hyperlink is larger than the maximum number of layers (step S601; N), it is determined that this hyperlink does not exist in the search range (step S602). If the number of layers of the hyperlink is smaller than or equal to the maximum number of layers (step S60)
1; Y), it is determined that this hyperlink exists in the search range (step S603).

FIG. 12 shows the flow of another example of the processing for determining whether or not the hyperlink is within the search range. Here, in addition to the determination based on the number of layers of hyperlinks, the determination based on the host name is added. The search range control unit 24 compares the number of hierarchies of the selected hyperlink with the maximum number of hierarchies (step S701), and when the number of hierarchies of hyperlinks is larger than the maximum number of hierarchies (step S701).
701; N), it is determined that this hyperlink does not exist in the search range (step S702). If the number of layers of the hyperlink is smaller than or equal to the maximum number of layers (step S701; Y), the attribute information about the link destination node indicated by this hyperlink is taken out from the node table 71 (step S703).

It is checked whether or not the host name included in the extracted attribute information of the link destination node partially matches the character string specified as the host name in the search range (step S7).
04). If there is a partial match (step S704;
Y), it is determined that the preceding hyperlink exists within the search range (step S705). If there is no partial match (step S705; N), it is determined that the hyperlink does not exist within the search range (step S702).
Here, the number of layers is determined, and then the partial matching of host names is determined, but the order may be changed.

FIG. 13 shows the flow of the table updating process shown in FIG. This processing is performed by the file collection unit 21 and the hyperlink extraction unit 22. First, the attribute information of the hyperlink determined to exist within the search range in step S504 of FIG. 10 is read from the link table 81 (step S801).
Here, if the number of read hyperlink layers is n
And Next, the attribute information of the node corresponding to the link destination node identifier of this hyperlink is displayed in the node table 71.
Is read from (step S802).

The file collection unit 21 initializes a communication buffer (not shown) used for communication with the server machine and a temporary buffer, and then connects to the server machine to prepare to read the document file of the link destination node indicated by the hyperlink. Is performed (step S803). Subsequently, the file collection unit 21 starts the transfer of the document file according to the transfer protocol of the distributed hypermedia system.

The file collection unit 21 reads the transfer protocol message header portion (step S804), and if the description language of the document file is not in the hypermedia description language format (step S805; N), reads up to the end of the document file. (Step S806). Then, post-processing such as releasing the communication buffer and the temporary buffer and disconnecting the connection with the server machine is performed (step S807), and the processing ends (end).

When the read file is in the hypermedia description language format (step S805; Y), the file collection unit 21 reads the document file of the transfer protocol message body into the communication buffer (step S808). Next, the start character to the end character of the tag representing the hyperlink part is moved to the temporary buffer (step S809), and the part describing the link destination node is extracted from the hyperlink stored in the temporary buffer ( Step S810). Number of layers calculation unit 2
7 is “n +” as the number of layers of the extracted hyperlink.
1 "is set (step S812).

The node / hyperlink attribute information thus obtained is stored in the node / link information database 23.
It writes in the node table 71 and the link table 81 therein (step S812). At this time, some partial items of the attribute information of the link source node and the attribute information of the link destination node, and all items of the hyperlink attribute information are written. As a result, the attribute information about the link destination node of the currently read node and the hyperlink from the read node to the link destination node are registered.
However, if a hyperlink having the same link source and link destination has already been registered, additional registration in the table is not performed, and only the search date and time is updated. This avoids multiple registration of the same node or hyperlink.

Next, it is checked whether or not processing has been performed up to the end of the document file of the node read this time (step S813). If the end has not been reached (step S).
813; N), and returns to step S808. Each node is
Since there may be a plurality of link destination nodes, by repeating this processing until the end of the file, all the link destination nodes of the node read this time are registered in the node table and the link table. When processing is performed up to the end of the file (step S81
3; Y), and the process ends (end).

The contents of the attributes registered in the node table 71 and the link table 81 in step S812 of FIG. 13 will be described. The node read from the server machine is the link source node, and the node described in the hyperlink included in this node is the link destination node. First, the last update date / time 41 is registered for the link source node. For example, in the node table 71 shown in FIG. 8, it is assumed that the node having the node identifier “1” is read from the server machine and the node having the node identifier “2” is described as the destination pointed to by the hyperlink. In this case, the node identifier is "1"
Is the link source node, and the node with the node identifier “2” is the link destination node.

The last update date and time enclosed by the dotted line 73 in FIG. 8 is updated as the attribute information of the link source node. The portion enclosed by the dotted line 74 in FIG. 8 is registered as the attribute information of the link destination node. That is, the registration date and time, which is the date and time registered in the scheme, the host name, the port number, the scheme specific part, and the database corresponding to the node identifier and the character string of the URL indicating the position of the node. As the node identifier, the one automatically generated by the DBMS is registered.

In the link table 81, the link identifier automatically generated by the DBMS, the link source node identifier, the link destination node identifier, the number of layers, and the search date and time are registered. An example will be described with reference to FIG. It is assumed that the node having the node identifier “1” as the link destination is read based on the hyperlink having the link identifier “1”. It is assumed that the node identifier "2" and the node identifier "3" are linked by the hyperlink described in the read node.

At this time, since the search is performed by referring to the hyperlink 84, the time is registered as the search date / time 85. Next, the link identifier for the newly obtained hyperlink is acquired from the DBMS and registered in the link identifier column for additional registration. For example, the link identifier (8) of the hyperlink (86) whose link identifier is "2"
Register “2” as 7). This value is an ID number that is appropriately given by the DBMS based on the registration order of the table.

The link source node of the hyperlink 86 is
Since the value of the node identifier is “1”, “1” is registered as the link source node identifier 88. Further, in the link destination node identifier 89, the value of the node identifier given by the DBMS when registering the attribute of the link destination node in the node table 71, that is, "2" is registered. Further, since the number of layers 91 is a hyperlink obtained from a node obtained by tracing a hyperlink having the number of layers “0”, a value “1” obtained by adding “1” to “0” is registered. Hyperlink 9 to the node whose node identifier is "3"
The second step is also registered by the same procedure. The information of the range shown by the dotted line 93 in FIG. 9 is registered for the additionally registered hyperlink.

The node table 71 and the link table 81 are updated each time a new link destination is found by reading the link destination node from the server machine based on one hyperlink. Therefore, when the table update process (step S505) is completed for one node in the flowchart of FIG. 10 and the process returns to step S502, the hyperlink newly registered in the table update process also becomes the search target. As a result, the search for link destinations proceeds one after another. However, the search range is limited by conditions such as the number of layers.

Since the unsearched determination criterion is that the search date and time is undefined or a time that is past the elapsed time or more, the hyperlink searched once is not checked again. As a result, for example, even if the link destination of the node “A” is the node “B” and the destination destination of the node “B” is the node “A”, a loop is formed by the links. The hyperlink from "" to the node "B" is not checked again, and the loop is not traced up to the maximum number of layers.

Thus, even if the search range is limited based on the number of layers of hyperlinks, the same effect as when the search range is limited based on the number of layers of nodes can be obtained. However, when giving the number of layers to the hyperlink, it is necessary to also refer to the node table in order to check the link destination node of the hyperlink obtained by referring to the link table. The reference processing of the table is increased as compared with the case where the number is added.

[0092]

As described in detail above, according to the inventions of claims 1 to 3, since the search range is limited by the number of layers from the starting node, the node to be searched is the starting point. Only those that have a strong semantic connection with the node. Further, since the search range can be limited by the number of layers, it is possible to collect only the information within the required range.
Further, since unnecessary nodes are not searched, the load on the server and the communication line between the servers can be reduced and the time required for the search can be shortened.

According to the fourth aspect of the present invention, since the node that has been read once is prevented from being read again, it is possible to avoid repeatedly searching the looped range. This allows the search to be performed efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of a node / link search device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of registered contents of a node table.

FIG. 3 is an explanatory diagram showing an example of registered contents of a link table.

FIG. 4 is a flowchart showing a flow of operations performed by a node / link search device.

FIG. 5 is a flowchart showing the flow of processing when determining whether or not a node exists within the search range.

FIG. 6 is a flow chart showing the flow of another example of the processing for determining whether or not the node exists within the search range.

FIG. 7 is a flowchart showing a flow of the table updating process shown in FIG.

FIG. 8 is an explanatory diagram showing an example of registered contents of a node table used in a node / link search device of a modified example.

FIG. 9 is an explanatory diagram showing an example of registered contents of a link table used in a node / link search device of a modified example.

FIG. 10 is a flowchart showing a flow of operations performed by a node / link search device in a modified example.

FIG. 11 is a flowchart showing the flow of processing when determining whether or not a hyperlink exists within the search range.

FIG. 12 is a flowchart showing another example of the processing for determining whether or not the hyperlink exists within the search range.

13 is a flowchart showing the flow of the table update processing shown in FIG.

FIG. 14 is an explanatory diagram showing an example of nodes and hyperlinks connecting these nodes.

FIG. 15 is an explanatory diagram showing an example of a relationship between documents of a node.

FIG. 16 is a block diagram showing an outline of a configuration of a conventionally used node / link search device.

[Explanation of symbols]

 11 node / link search device 12 network 13 server machine 21 file collection unit 22 hyperlink extraction unit 23 node / link information database 24 search range control unit 25 system control unit 26 hypermedia description language analysis unit 27 hierarchy number calculation unit 28 host name Comparison unit 29 Number of layers comparison unit 31, 71 Node table 51, 81 Link table

Claims (4)

[Claims] 1. A search from an arbitrary node to a link destination node is sequentially performed based on link information indicating a name of a link destination node and a storage position of the link destination node included in each node of the hypertext. Search condition setting means for setting the limiting condition of the search range at the time of execution as the maximum value of the number of layers, which is the number of nodes existing between the node that is the starting point of the search and the node of the search destination, and the link information File collection means for repeatedly reading the content of the linked node from the server that stores it, starting from the node that is the starting point of the search, and the node for each time the content of one node is read by this file collection means Node that stores the link information included in and the information indicating the correspondence between the node of the link destination indicated by this and the node read this time. Link information storage means, a layer number calculation means for obtaining the layer number of the node of the link destination indicated by the link information contained in the node each time the content of one node is read by the file collection means, and the layer number calculation means And a search range limiting means for stopping the reading by the file collecting means of the contents of the nodes linked after the node read this time when the obtained number of hierarchies is larger than the maximum value of the number of hierarchies set by the search condition setting means. A node / link search device comprising: 2. A search from an arbitrary node to a link destination node is sequentially performed based on link information indicating the name of the link destination node and the storage location of the link destination node included in each node of the hypertext. Search condition setting means for setting the search range limiting condition when performing the search as a maximum value of the number of layers, which is the number of links existing from the node that is the starting point of the search to the node of the search destination, and the link information File collection means for repeatedly reading the content of the linked node from the server that stores it, starting from the node that is the starting point of the search, and the node for each time the content of one node is read by this file collection means Node that stores the link information included in and the information indicating the correspondence between the node of the link destination indicated by this and the node read this time. Link information storage means, a layer number calculation means for obtaining the layer number of the link to the link destination node represented by the link information contained in the node each time the content of one node is read by the file collection means, and the number of layers When the number of layers obtained by the calculation means is larger than the maximum value of the number of layers set by the search condition setting means, the search range for stopping the reading of the contents of the node linked after the node read this time by the file collecting means A node / link search device comprising: a limiting unit. 3. The node according to claim 1, wherein the nodes to be searched are distributed and stored in a plurality of servers connected to the network.
Link search device. 4. The file collection means, the same node determination means for determining whether the node of the link destination indicated by the link information included in the node read this time is the same as the node already read, 3. The node according to claim 1 or 2, further comprising: multiple read stop means for stopping the re-reading of the node when it is judged to be the same as the node already read by the same node judging means. -Link search device.