Abstract:
An information accessing method permits the user data belonging to a client-server system to be accessed by a user belonging to another client-server system under proper security and controls the permission for accessing the user data according to the security ranks of the user whose data is to be accessed and the user who wants to access the data. When a client unit issues a request for accessing the user data of the user belonging to the other client-server system, the request for access is sent to an ID conversion unit through a user ID management unit. The ID conversion unit operates to convert a user ID into a guest ID by referring to an ID conversion table, and then sends the request for access to a user ID management unit. The user ID management unit makes sure that the guest ID is registered by referring to the user ID table. Then, the request for access is sent to the user data management unit through security check units, so that the whole or the open portion of the user data specified on the user data is allowed to be accessed.

Description:
This is a continuation application of U.S. Ser. No. 09/404,254, U.S. Pat. No. 6,240,518 filed Sep. 22, 1999, which is a continuation application of U.S. Ser. No. 09/160,287, filed Sep. 25, 1998, now U.S. Pat. No. 6,092,203, which is a continuation application of U.S. Ser. No. 08/756,605, filed on Nov. 26, 1996, now U.S. Pat. No. 5,822,518. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to an information accessing method for accessing information held in a server unit included in a client-server system, and more particularly to the information accessing method that is effective when a client unit located in a client-server system accesses information held in a server unit located in another client-server system through a network having two or more client-server systems connected therein. 
     As a method for accessing information held in a data file to be tightly secured, a method has been proposed for restricting access to such a data file with a user ID or a password. With this method, a client-server system takes the steps of registering in a server unit a user ID or a password with which access is permitted in a client-server system having the server unit, comparing a user ID or a password which the user inputs with the user ID or the password registered in the client-server system, and permitting access to a data file contained in the server unit only if both of the user ID and the password are matched to each other. If a user or a user group of specific users belonging to a section of a company makes access to a data file, some access levels are set according to the position of each user in the company. Each access level may reach the corresponding portion of the data file to be accessed. Those access levels are used for access restriction such as disability to access the data file, ability only to access a data file, and ability to update a data file. 
     When a data file registered in a client-server system is accessed by a client unit of another client-server system in a network such as a communication tool having two or more client-server systems connected therethrough, the client unit pre-registers a guide ID in the client-server system having the data file to be accessed so that the client unit may access the data file in the different client-server system from the system to which the client unit belongs. 
     SUMMARY OF THE INVENTION 
     If the foregoing client-server system is applied to a system for managing a schedule, the information to be secured is a schedule of each user. 
     For example, a person who would hold a meeting, a host of the meeting needs to access a schedule on the meeting day of each meeting participant for the purpose of checking if each participant&#39;s schedule is open. If, however, any one of the participants belongs to the management of a different client-server system from the system of the host, in the current state, the client-server system of the participant is configured to unconditionally permit the host to access to his or her schedule or prohibit the host to do so. 
     The personal schedule contains one portion that is open to any user of the client-server system such as appointed day and hours and the other portion that is not open to all the users of the system such as a destination of a business trip or a dealer. The current system does not provide a capability of fine restricting the data to a portion to be accessed or a portion not to be accessed according to the relation between the user to be accessed and the user who would access the data. 
     It is an object of the present invention to provide an information accessing method that permits a user of a client-server system to access the user data of another client-server system under proper security. 
     It is another object of the present invention to provide an information accessing method that controls permission to access the user data according to the corresponding relation of a security rank between a user to be accessed and a user who would access the user data. 
     Later, the term “system” means a system having a function of storing user data for each user, registering as a user ID an ID of a user permitted to access the user data and specifying the range of the registered user ID as the managing range of the system itself. The present invention is characterized to offer a security method that is arranged to convert a first user ID belonging to the managing range of a first system into a second user ID (guest ID) belonging to the managing range of a second system and permit the user to access the user data if the second user ID and a third user ID for an owner of the user data belong to the second system. 
     Further, the information accessing method according to the present invention is configured to set one of plural security ranks to each user, set a table for determining if the access to the user data is permitted from a security rank of a user for requesting the access to the user data and a security rank of a user whose data is accessed by the former user, and determine if the access to the user data is permitted by referencing this table if requested to access the user data. 
     When the user with the first user ID logs in the first system or issues a request for access to the user data, the first user ID is checked by the first system. When the user with the first user ID issues a request for accessing the user data of a second system, it is checked if the first user ID is registered in the ID conversion table. When the request for access is passed to the second system, it is checked if a second user ID is registered in the ID conversion table. That is, three checks are executed until the user of one system is permitted to access the data of the user belonging to the other system. After these checks are done, the user with the first ID enables to access the whole user data managed by the second system. Further, the use of the security rank makes it possible to determine if the access to at least part of the user data is permitted on the basis of the security rank of the user for issuing a request for access and the security rank of the user whose data is to be accessed. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing an overall configuration of a system according to the present invention; 
     FIG. 2 is a table showing a data format of an ID conversion table  14  according to an embodiment of the present invention; 
     FIG. 3 is a table showing a data format of a user ID table  11  according to an embodiment of the present invention; 
     FIG. 4 is a table showing a data format of a security table  12  according to an embodiment of the present invention; 
     FIG. 5 is a table showing a data format of user data  13  according to an embodiment of the present invention; and 
     FIG. 6 is a flowchart showing a flow of process located between the systems according to an embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Later, the description will be oriented to a schedule management to which an embodiment of the present invention is applied with reference to the drawings. 
     FIG. 1 is a block diagram showing a basic system arrangement for describing an embodiment of the present invention. In the present invention, a term “client-server system” means a system configured to connect at least one client unit ( 20 ) to at least one server unit ( 10 ) so that the server unit of this system manages data ( 41 ) of the user who uses the client unit of this system. 
     FIG. 1 shows a system configuration having two such client-server systems ( 100 ,  500 ) connected through a network  90 . A numeral  10  denotes a server unit for managing a schedule of a user. A numeral  20  denotes a personal computer (PC) that is a client unit for accessing the server unit  1  through a local area network  30  (LAN). In FIG. 1, one PC  20  is connected to the LAN  30 . In actual, two or more PCs may be connected to the LAN  30 . A numeral  41  denotes a user data registration unit for registering a schedule of each user. The schedule registered in the registration unit  41  comprises an open portion  411  and a closed portion  412 , both of which are shown in FIG.  5  and will be discussed below. A numeral  43  denotes a user ID table for registering a user ID that is permitted to access the user data held in the client-server system to which the user with the user ID belongs. A numeral  42  denotes a security table registering unit for registering a security table for determining if the closed portion  412  of the schedule of the target user is to be accessed according to the security ranks of the user who would like to access the data and the user to be accessed, which will be discussed in detail with reference to FIGS. 3 and 4. A numeral  44  denotes an ID conversion table registering unit for registering an ID conversion table for registering the corresponding relation between the user ID and the guest ID (which belongs to another schedule managing system). A numeral  11  denotes a LAN control unit for controlling communication between the server  10  and the PC  20  through the LAN  30 . A numeral  90  denotes a network such as a public line, a private line, and a trunk LAN connected to two schedule management systems ( 100 ,  500 ). A numeral  16  denotes a gateway for controlling communication between the two schedule managing systems through the network  90 . A numeral  12  denotes a user ID management unit that is operated to reference the user ID table registering unit  43  for checking the user ID sent from the PC  20  and the guest ID sent from the other schedule management system and to obtain an address of the PC from the user ID. A numeral  13  denotes a security check unit that determines if the access to the closed portion  412  of the schedule of the target user is permitted by referring to the security table registering unit  42 . A numeral  14  denotes a user data management unit that is operated to read schedule information of the user requested by the PCs ( 20 ,  60 ) and send the data permitted as a result of the determination of the security check unit  13  to the PC  20  or the other system  500  through the user ID management unit  12  or the gateway  16 . A numeral  15  denotes an ID conversion unit for converting the user ID into the guest ID by referring to the ID conversion table  44 . In FIG. 1, the network  90  is served to connect the schedule management system ( 100 ) shown in the left hand with the other schedule management system ( 500 ) shown in the right hand, each of which has the same functional configuration as each other. The server unit  10  is an information processing apparatus such as a PC or a workstation. The user ID management unit  3 , the security check unit  4 , the user data management unit  5 , the ID conversion unit  6  and the like are realized by executing a program stored in a storage unit (not shown) of this information processing apparatus. 
     FIG. 2 shows an example of a data format of the ID conversion tables ( 44 ,  84 ). The ID conversion table ( 44  or  84 ) has a corresponding relation set between the user ID and the guest ID. The user ID is a user identifier registered in the user ID table registering unit  43  included in the client-server system (for example,  100 ) to which the user belongs. The guest ID is a user identifier registered as a user ID in the user ID table registering unit  84  included in the other client-server system (for example,  500 ). If one client-server system includes as a participant the user permitted to access the other client-server system, the guest ID is registered as a guest ID in the ID conversion table included in the latter client-server system. If one client-server system does not include the user permitted to access the other client-server system, the guest ID is not registered in the ID conversion table of the, latter system. The guest ID may be used in duplicate. Hence, two or more users may use one guest ID. 
     FIG. 3 shows an example of a data format of the user ID table  430  registered in the user ID table registering unit  43 . This table is used for registering the user(s) permitted to access the user data registering unit  41 . The table contains the identifiers of the users belonging to the managing range of the schedule management system. Each entry is composed of a user ID  431 , a security rank  432  and attribute information  433  of a user. The security rank  432  indicates a rank or a level of the security. In this example, the entry having the user ID  431  of “B001” and “B002” indicates the registration of the guest ID as the user ID. 
     FIG. 4 shows an example of a data format of the security table  420  registered in the security table registering unit  42 . The security table  420  indicates an access right to the closed portion of the schedule for each security rank  432 . An alphabet on an abscissa axis indicates a security rank of a user to be accessed, while an alphabet on an ordinate axis indicates a security rank of a user who wants to access the user data. In the access right, a value of “1” indicates access enabled, while a value of “0” indicates access disabled. In this table, assuming that the top rank is A and the rank goes down one by one from A to Z, this table is an example of a common security management, in which if (the security rank of the user who wants to access the data)≧(the security rank of the user to be accessed), the user who wants to access the data is always permitted to access the data, while if not, he or she is not permitted to access the data. In actual, this data format does not need the table, because the access right can be obtained by comparing the security rank of both of the users with each other. However, if the access right is obtained from the security ranks of the user who wants to access the data and the other user to be accessed in a complicated manner, the security table  420  is necessary. 
     FIG. 5 shows an example of a data format of the user data  410 . The user data  410  stores the schedules of the users as the user data of two or more users. The user ID  431  is an ID number indicating an owner of the user data to be accessed. In the schedule information of each user, the open portion  411  is a portion to be accessed by any user irrespective of the access right. Concretely, the open portion  411  corresponds to a day and a time portion of the schedule. In particular, the open portion  411  indicates to any user only a free time an the schedule of the user to be accessed. The closed portion  412  indicates the data to only the user who has an access right and contains private information or information about a trade secret such as a destination of a business trip and an important matter on business. 
     Herein, the description will be oriented to the actual procedure for accessing the schedule data. 
     At first, the description will be oriented to the procedure about how the user of the PC  20  served as a client unit of the client-server system  100  makes access to a schedule of the user registered in the system  100  itself. 
     The user of the PC  20  (User ID: C003) issues a request for accessing the schedule data included in his or her own system to the LAN control unit  11  of the server unit  10  through the LAN  30  by transmitting the data for specifying the user ID of his or her own and the user to be accessed (such as an employee number, a name or a user ID of his or her own). The user ID management unit  12  is operated to check if the received user ID is the data of the user managed by the client-server system to which the management unit  12  belongs by referring to the user ID management unit  12 . In this case, the user ID indicates a user registered in that client-server system. Hence, the security rank (B) for the user ID is read from the server unit, and the data for specifying the ID of the user who wants to access the data, the corresponding security rank and the user to be accessed are passed to the security check unit  13 . Then, the security check unit  13  operates to determine if the access to the closed portion  412  of the requested schedule is permitted by referring to the security table registering unit  42  and then pass the determined result to the user data registering unit  14 . The user data managing unit  14  operates to access the user data registering unit  41  for reading the schedule data of the user to be requested to be accessed and transmitting the permitted portion to the PC  20  through the user ID management unit  12 , the LAN control unit  11 , and the LAN  30 . 
     In turn, the description will be oriented to the procedure about how a user of one schedule management system issues a request for access to a user of the other schedule management system. 
     FIG. 6 shows this procedure and a flow of process from when the PC ( 20 ) issues a request for accessing a schedule of another user to when the PC ( 20 ) obtains the requested schedule information. The PC ( 20 ) operates to issue to a server unit ( 10 ) a request for accessing a schedule with a user ID for issuing a request and the other user ID to be accessed of the other system (step  31 ). The user ID management unit  12  receives this request through the LAN  30  and the LAN control unit  11  (step  32 ), and stores the correspondence between the requested user ID and the physical address of the PC  20 . Next, the user ID management unit  12  operates to check the ID of the user for giving an accessing request by referring to the user ID table  43  (step  33 ) and then pass the control to the ID conversion unit  15  if the user to be accessed belongs to the different system from the system of the user who wants to access the data. The ID conversion unit  15  operates to convert the user ID into the guest ID by referring to the ID conversion table ( 44 ) (step  34 ) and transfer a request for access to the server unit  50  of the different client-server system  500  through the gateway  16  and the network  90  (step  35 ). If the user ID is not registered in the ID registration table  44 , the ID conversion unit  15  rejects the request for access. The request for access contains a guest ID, a user ID and a user ID of a user to be accessed. The user ID management unit  52  of the server unit  50  receives the request for access (step  36 ) and checks if the guest ID and the user ID  431  of the user to be accessed are registered in a user ID table registration unit  83  (step  37 ). If both of the IDs are not registered in the unit  83 , the user ID management unit  52  rejects the request for access. The user ID management unit  52  rejects the request for access containing the guest ID without through the gateway  56 . If both of the IDs are registered in the registration unit  83 , the user ID of the user for giving a request for access, its security rank  432 , the user ID of the user to be accessed, and its security rank  432  are passed to the security check unit  53 . The security check unit  53  operates to obtain an access right for the user for giving a request for access by referring to the security table  82  (step  38 ) and pass the user ID of the user for giving a request for access, the user ID of the user to be accessed and the access right to the user data management unit  54 . The user data management unit  54  operates to retrieve the data stored in the user data registering unit  81  and read the user data registered under the user ID  431  of the user to be accessed (step  39 ). If the access right is enabled, the overall schedule information is transferred to the server unit  10  through the gateway  56  and the network  90 , while if the access right is disabled, only the open portion  411  of the schedule information is transferred to the server unit  10  (steps  40  and  41 ). This schedule information contains the user IDs of the user for giving an access request and the user to be accessed. The user ID management unit  12  receives this schedule information (step  42 ) and obtains a physical address of the PC  20  from the user ID of the user for giving an access request and transmits the schedule information to the PC  20  which issues an access request through the LAN control unit  11  and the LAN  30  (step  43 ). The PC  20  receives this schedule information (step  44 ) and displays it on the display unit. 
     In the foregoing embodiment, when the PC ( 20 ) makes access to the server unit, the user ID of the requester is sent with the information for specifying the user to be accessed (such as an employee number, a name and a user ID). Instead, the user ID of the requester is sent to the server unit. Then, the state of the client-server system permitted to be accessed by the user ID is checked (Concretely, the indexes such as a name and an employee number about the user data permitted to be accessed are output to the client unit.) Next, the information for specifying the user to be accessed may be input to the server unit. 
     Further, in the foregoing embodiment, the gateway ( 16 ,  56 ) is provided inside of the server unit ( 10 ,  50 ). In place, the gateway ( 16 ,  56 ) may be located independently of the server unit ( 10 ,  50 ). In place of the gateway ( 16 ,  56 ), another inter-network connecting unit such as a router may be selected according to the type of the network  90 . Or, a simple communication control mechanism of the network may be utilized. Moreover, in the foregoing embodiment, the user ID of the requester is transferred from the server unit  10  to the server unit  50  and then returns to the server unit  10 . This is an ID for taking correspondence with the PC  20 . In place of the user ID, it may be replaced with a transaction ID numbered by the user ID management unit  12 . The content of the user data  431  is not limited to the information about the schedule of the user. It may be any data. The user data  431  is divided into the open portion  411  and the closed portion  412 . In actual, all of the user data  431  may be the open portion. In this case, the security rank  432 , the security table  420  and the security check unit  13  are not necessary. On the contrary, all of the user data may be the closed portion. 
     In the foregoing embodiment, one schedule management system is configured of just one server unit. In place, it may employ a multi-server system and therefore be configured of two or more server units. The schedule management system configured as described above has two or more server units connected through one LAN, one of which server units has a gateway and the others of which server units do not have gateways. The content of the user ID table  430  is the same in any server unit included in the system. Each server unit takes the responsibility of the corresponding user group. The flow of process of the multi-server type schedule management system is the same as the flow of process shown in FIG. 6 from the steps  31  to  36 . At a step  37 , it is checked if the guest ID and the user ID  431  of the user to be accessed are registered by referring to the user ID table  430 . If both of the IDs are registered, it is determined if the user ID of the user to be accessed belongs to the user group to be processed by the server unit. If the request for accessing the schedule may be processed by the server unit, the flow of process from the subsequent steps  38  to  44  is the same as the flow of process shown in FIG.  6 . If the user ID of the user to be accessed belongs to a user group to be processed by another server unit included in the same information management system, the user ID and its security rank are sent to that server through the LAN control unit and the LAN. Then, this server is operated to perform the process from the steps  38  to  40  and then send the schedule information to the server  1 - 2 . The server unit operates to just relay the schedule information and then send it to the server unit through the gateway. The flow of process from the subsequent steps  42  to  44  is the same as the flow of process shown in FIG.  6 . As mentioned above, the multi-server type information management system enables to distribute the user data  410  and the processing load to two or more server units. 
     As set forth above, according to the present invention, the user who passes the checking gates of the user ID and the guest ID can make access to all the user data belonging to the other system. Further, the system provides a capability of fine controlling the access right to the closed portion of the user data according to the security ranks of the user to be accessed and the user for giving an access request.