JP2003150595A - Database system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a database system for minimizing access to a data server by constructing database processing dispersedly into a client terminal and the data server. SOLUTION: This database system is composed of the client terminal 3 having a local database 5, and the data server 1 connected to this client terminal 3 via a communication transmission passage 2, and having an RDB 4 being a database and a DB version control table 7 for recording version information on the RDB 4 and version information on the database 5. When a retrieval request is made for the client terminal 3, the client terminal 3 inquires of the server 1 about a version of the one's own database 5, retrieves the one's own database 5 when confirming the fact of being the newest version, and retrieves the database after renewing the one's own database by acquiring difference information on the database from the data server 1 when the newest version cannot be confirmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database system having a data search and acquisition function between a data server and a client terminal connected by a communication medium.

[0002]

2. Description of the Related Art FIG. 4 is a system configuration diagram showing a conventional data management system, which is a data management system in which a data server and a client terminal are connected by a communication medium. In FIG. 4, 1 is a data server, 2 is a communication transmission line, 3 is a client terminal (1 to N) connected to the data server 1 via the communication transmission line 4, and 4 is the data server 1.
RDB (relational)
database). FIG. 5 is a sequence diagram showing a data request / acquisition process in the conventional data management system.

Next, the operation will be described with reference to FIG. In this type of data search / acquisition method, a data search / acquisition request is made from the plurality of client terminals 3 (1 to N) to the data server 1 implementing the RDB 4. In the data server 1, in response to these data search / acquisition requests received from each client terminal 3, the data matching the conditions is searched and acquired from the RDB 4 and transmitted to the requesting client terminal 3.

[0004]

Since the conventional data search / acquisition request between the data server and the client terminal has been processed as described above, the data server 1
On the side, when data search / acquisition requests are simultaneously received from a plurality of client terminals 3, batch processing is performed, and thus a large amount of data processing performance is required. Also, when the load is high, it is impossible to process the data search / acquisition request, and the DBMS (data)
There is a drawback in that the CPU is occupied for a long time due to the base management system) processing.

To solve this problem, Japanese Patent Laid-Open No. 11-1950
In Japanese Patent Publication No. 29, in response to a search request from a client terminal to a data server, a search program (applet) for acquiring data corresponding to a search condition from a database and performing a search for the acquired data is added to the client terminal. A sending system has been proposed. The purpose of this proposal is to restrict the execution of similar search operations to the data server in order to further narrow down the data once acquired (the applet sent to the client terminal at the same time as the data acquired in the initial search). By further narrowing down the data acquired in the client terminal), the load required for data search is reduced. However, in this proposal, when the initial search requests from a plurality of client terminals occur simultaneously, the data server once processes the respective requests in a batch. Therefore, an increase in the DBMS load on the data server cannot be denied when a large number of search requests are simultaneously issued from a plurality of client terminals. Further, in the method proposed by Japanese Patent Laid-Open No. 11-195029, when the communication line is disconnected, the client terminal cannot execute the initial search request or the data update request to the data server, and the data operation is not possible at all. There is also the problem that

The present invention has been made in order to solve the above-mentioned problems and provides a database system in which database processing is distributed and constructed in client terminals and data servers, and access to the data servers is suppressed as much as possible. Is the primary purpose. In addition, even when the communication between the data server and the client terminal is disconnected,
The second purpose is to obtain a database system that can continue data search / screen display operations or data registration / update operations on the client terminal side.

Further, when the data server and the client terminal are connected by a public communication medium, database processing can be performed in a state where the network connection is cut off, except for processing for fetching the latest information from the data server to the client terminal. The third purpose is to obtain a database system. In addition, client terminals and mobile terminals connect to the network by dial-up, etc.
When the client is temporarily connected to the data server and used only when necessary, the client terminal can execute data search display / store even when disconnected from the data server, and the software cost of the client terminal at this time is suppressed. The fourth purpose is to obtain a database system that can

[0008]

In a database system according to the present invention, in a database system in which a data server and a plurality of client terminals are connected via a communication transmission line, a data server having a first database, A client terminal having a second database composed of data for a predetermined period recorded in one database, wherein the client terminal is
When a search request occurs, the data server is queried for the version of the second database, and the data server confirms the match with the version of the first database before searching the second database.

Further, the data server transmits the difference information between the first database and the second database to the client terminal when the version of the first database is newer than the version of the second database of the client terminal. It is a thing. Further, when the communication transmission line is disconnected, the client terminal searches the second database.

Further, when the second database is updated by the client terminal when the communication transmission line is disconnected, the client terminal is updated during disconnection in response to restoration of the disconnected communication transmission line. The second is to notify the data server of update information of the database. Further, when the client terminal updates the second database, the client terminal manually notifies the data server of the update information.

The second database is composed of XML files.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a block diagram showing a database system according to Embodiments 1 and 3 of the present invention. In FIG. 1, 1 is a data server, 2 is a communication transmission line, and 3 is a client terminal (1 to 1 connected to the data server 1 via the communication transmission line 2.
N), 4 is RDB which is a database of the data server 1
(First database). Reference numeral 5 denotes a database (second database) managed on the client terminal 3, which stores the element name defined by the tag and the data itself by using an XML document or the like. The database 5 is composed of data stored in the data stored in the RDB 4 retroactively for a predetermined period from the latest, and the predetermined period is, for example, the number of years or months required by the system according to the capacity of the system. 6 is database 5
Is a style sheet such as XSLT used for data retrieval (data filtering) for. Reference numeral 7 is a DB version management table for managing the versions of the databases held by the respective devices of the data server 1 and the client terminal 3. Reference numeral 8 is an RD that receives data satisfying the conditions from the RDB 4 on the data server 1 and sends the data to the client terminal 3 based on the data search request received from the client terminal 3 or updates the data from the client terminal 3 by RD.
This is a DB processing function reflected in B4. 9 is the Web displayed on the client terminal 3 by the browser display function 10.
It is a search request function for receiving a data search operation on the screen and making a data search request to the database 5 or the RDB 4.

In FIG. 1, an RDB 4 is built in the data server 1. In RDB4, update date and time (2 digits for year, 2 digits for month, 2 digits for day, 2 digits for hour, 2 digits for minute, 2 digits for second) for each record
Is added. The data contents of the deleted record and the date and time of deletion (2 digits for year, 2 digits for month, 2 digits for day, 2 digits for hour, 2 minutes for minute)
It has a table for managing the deletion history (digits, 2 digits for second). Of the deletion history, the update (record deletion processing) of the database 5 of all client terminals 3 is deleted when the update of all terminals is completed.

The database 5 allows the application to determine what kind of data itself is based on the data element name, and can be easily processed as a database. The DB version management table 7 manages the versions (2 digits of year, 2 digits of month, 2 digits of day, 2 digits of hour, 2 digits of minute, 2 digits of second) of the database held by each device. The database version of the data server 1 is the database version of the client terminal 3 every time the RDB 4 is updated.
Every time data is acquired from the data server 1 and updated, the processing time (2 digits for year, 2 digits for month, 2 digits for day, 2 digits for hour,
2 digits for minutes and 2 digits for seconds) are entered.

Next, the operation relating to the data search request / acquisition will be described. In FIG. 1, the client terminal 3
More data search request occurs. In the search request function 9 on the client terminal 3, first, the data server 1
Database 5 held by client terminal 3 itself
Inquiry A is executed as to whether the version (XML file or the like) is the latest. At this time, the database version of the client terminal 3 itself is also transmitted. In the DB processing function 8 on the data server 1, after receiving the database version inquiry A from the client terminal 3, the database version of the data server itself managed by the DB version management table 7 and the received database version of the client terminal 3 The comparison B is executed. After that, transmission C of the database version comparison result (match / mismatch) is executed to the client terminal 3.

The client terminal 3 receives the database version comparison result by the transmission C. If the comparison result is a match, the style sheet 6 for performing data search (filtering) is applied to the locally managed database (XML file or the like) 5, and the data search D is executed. The search request function 9 acquires the search result E by the processing of the above-described data search D, and executes the screen display F of the search result on the browser display function 10. In the data server 1, when the result of the database version comparison process B does not match (the database version is newer than the database version managed by the client terminal 3 itself on the data server 1), the comparison to the client terminal 3 is performed next. The difference information of the acquired database is transmitted in accordance with the result transmission.

The difference information of the database is the update date and time (2 digits of year, 2 months of month) among the records held in RDB4.
(Digit, 2 digits for day, 2 digits for hour, 2 digits for minute, 2 digits for second) are newer than the database version of the client terminal 3, and a record deletion history newer than the database version of the client terminal 3 from the table managed as the deletion history. It has been acquired H. The client terminal 3 updates the database 5 managed by itself from the difference information of the database received by this processing. After the update ends normally, the own DB version in the DB version management table 7 on the data server 1 is updated. After that, the search request function 9 executes a data search process on the updated database 5.

According to the first embodiment, even when a plurality of client terminals 3 exist and a large number of data search requests occur simultaneously, the data server 1 has a mismatched database version by the above-described processing. The difference data is transmitted only to the terminal 3 by the RDB process, and the client terminal 3 having the same database version is searched for the local database 5 held by the client terminal. The load is distributed to the respective client terminals 3, and the high load due to executing the database search processing for all the client terminals on the data server 1 can be avoided.

Embodiment 2. 2 is a block diagram showing a database according to the second embodiment of the present invention. In FIG. 2, 1 to 5 are the same as those in FIG.

Next, the operation will be described. In FIG. 2, first, the communication between the data server 1 and the client terminal 3 is disconnected. Even in the state where the communication is disconnected, the client terminal 3 retains the database 5 (XML file or the like) locally, so that the operation of data search or data update can be continued. When communication between the data server 1 and the client terminal 3 is restored, the data server 1 is notified of the processing (data search and data update) executed for the database 5 while the client terminal 3 is disconnected, and the data server 1 RDB4 is updated.

The update of the RDB4 on the data server 1 is realized by transmitting the XML file on the client terminal 3 to the data server 1 and reflecting this on the RDB4. When data is updated to a certain record on the RDB4, there is a possibility that the record on the RDB4 has already been updated by another client terminal during the communication disconnection described above. At this time, the update date and time (2 digits for year, 2 digits for month, 2 digits for day, 2 digits for hour, 2 minutes for minute) in the record in RDB4
(Digit, second digit), update date and time (year two digits, month two digits, day two digits, hour two digits, minute two digits, second two digits) when the client terminal 3 updates the record in the local XML file. )
If is old, the data update process for this record is not performed. This ensures the validity of the time series of data updates. After the data update processing on the RDB4 from the client terminal 3, the data managed by the RDB4 is again acquired by the client terminal 3 and the information update (update of the XML file) is executed, whereby the database on the RDB4 and the client terminal 3 is updated. 5 (XML file etc.) can be ensured.

According to the second embodiment, even if the communication between the data server and the client terminal is cut off, the client terminal can perform local data search and ensure system consistency when restored. .

Embodiment 3. The third embodiment will be described with reference to FIG. In the third embodiment, in FIG. 1, an inquiry A to the data server as to whether the version of the database 5 (XML file or the like) held by the client terminal 3 itself is the latest, and information of the database when the version is not the latest The update is a system for manually executing an operator operation of the client terminal 3.

When a search request is generated by the operation of the client terminal 3, the search request function 9 has a database 5 (XML file or the like) that is locally held by itself.
The search process is executed for. Further, also when registering or updating new information of data, data registration or updating is performed with respect to the database 5 (XML file or the like) held locally in the client terminal 3. After completing the data processing to some extent, the operator requests the data server 1 to update the database by manually operating the screen.
As a result, communication connection to the data server 1 and DBMS processing do not occur for each data update processing. Therefore, if the data is registered or updated by mistake, the communication connection and the DB are wasted due to the operation being redone.
MS processing can be suppressed, which can reduce communication costs and DBMS load.

According to the third embodiment, it is possible to suppress communication connection and DBMS processing when executing data registration and update,
Communication costs and DBMS load can be reduced.

Fourth Embodiment FIG. 3 is a diagram showing the software configuration of the database system according to the fourth embodiment of the present invention. In FIG. 3, reference numerals 3, 5, and 6 are the same as those in FIG. 11 is OS, 12 is JD
K [Java (registered trademark) Development
Kit: Java (registered trademark) program development environment / execution environment], 13 is a servlet engine, and 14 is an HTT
P service, 15 is a browser for displaying a Web screen, and 16 is an XML document creation function for updating data in the database 5 (XML file or the like) held by the client terminal itself. Reference numeral 17 denotes an XML document search function for executing a search on the database 5 (XML file or the like) held by the client terminal itself.

Next, the operation will be described. Generally, when a database management function is realized, generally expensive general-purpose RDBMS (relational database) is used for storing and managing data and for manipulating data.
ase management system) software is required. When it becomes necessary to implement the database management function in all of the plurality of client terminals in the system configuration shown in FIG. 4 due to system use or the like, at present, it is necessary to implement the above-mentioned RDBMS software in each client terminal. As the number of client terminals increases, the system construction cost (RDBMS software purchase cost) will increase.

In the fourth embodiment, an XML file or the like is applied to construct the database 5 in the client terminal 3. The data element name defined by the tag such as XML and the data itself are saved in a file. By this data element name, the application can easily determine what kind of data itself is, and it becomes possible as a database. Further, data operations such as searching for the database 5 on the client terminal 3 are realized by applying the sentence conversion style sheet 6 such as XSLT and extracting the data from the database 5 constructed by the XML file described above. .

According to the fourth embodiment, it is not necessary to purchase and install the RDBMS software for each client terminal, and the system construction cost (RDBMS software purchase cost) can be reduced.

[0030]

Since the present invention is constructed as described above, it has the following effects. In a database system in which a data server and a plurality of client terminals are connected via a communication transmission line, a second server including a data server having a first database and data for a predetermined period recorded in the first database When a search request occurs, the client terminal queries the data server for the version of the second database, and the data server confirms the match with the version of the first database. Since the second database is searched after that, it is possible to disperse the load required for the data search when a large number of data search requests are generated by a plurality of client terminals.

Further, the data server transmits the difference information between the first database and the second database to the client terminal when the version of the first database is newer than the version of the second database of the client terminal. Therefore, the difference information may be transmitted only when the version of the first database is newer than the version of the second database, and high load can be avoided.
Further, since the client terminal searches the second database when the communication transmission path is disconnected, the client terminal can perform the search even when the communication transmission path is disconnected.

Further, when the second database is updated by the client terminal when the communication transmission line is disconnected, the client terminal is updated during disconnection in response to restoration of the disconnected communication transmission line. Since the update information of the second database is notified to the data server, it is possible to ensure the consistency of the data of the first database and the data of the second database when the communication transmission path is restored from the disconnection. Also, when the client terminal updates the second database, the update information is manually notified to the data server, so that the update information can be transmitted collectively.
Communication connection and DBMS processing can be suppressed.

Since the second database is composed of XML files, the system construction cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a database system according to first and third embodiments of the present invention.

FIG. 2 is a block diagram showing a database according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a software configuration of a database system according to a fourth embodiment of the present invention.

FIG. 4 is a system configuration diagram showing a conventional data management system.

FIG. 5 is a sequence diagram showing a data request / acquisition process in a conventional data management system.

[Explanation of symbols]

1 data server, 2 communication transmission line, 3 client terminal, 4 RDB, 5 database, 6 style sheet, 7 DB version management table, 8 DB processing function,
9 Search request function, 10 Browser display function, 11 O
S, 12 JDK [Java (registered trademark) Level
moment Kit], 13 Servlet engine,
14 HTTP services, 15 browsers, 16 XM
L document creation function, 17 XML document search function.

Claims (6)

[Claims] 1. A database system in which a data server and a plurality of client terminals are connected via a communication transmission line, the data server having a first database,
A client terminal having a second database composed of data for a predetermined period recorded in the first database is provided, and the client terminal inquires the version of the second database when a search request is made. To the data server, and after the data server confirms a match with the version of the first database, the database system is searched. 2. The data server, when the version of the first database is newer than the version of the second database of the client terminal, sends the difference information between the first database and the second database to the client terminal. The database system according to claim 1, wherein the database system transmits. 3. The database system according to claim 1, wherein the client terminal searches the second database when the communication transmission line is disconnected. 4. When the second database is updated by the client terminal when the communication channel is disconnected, the client terminal is updated during disconnection in response to restoration of the disconnected communication channel. The database system according to any one of claims 1 to 3, wherein the updated information of the second database is notified to the data server. 5. The database system according to any one of claims 1 to 4, wherein the client terminal manually notifies the data server of the update information when updating the second database. . 6. The database system according to claim 1, wherein the second database is composed of an XML file.