JP2017167958A - Database client, database client program, database client control method, and database system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a database client capable of executing a process on a database at such as data registration time without being affected by other database clients.SOLUTION: A database client according to the present invention comprises: maximum registration count acquisition means for acquiring the maximum number of items that can be registered in a database server; current registration count acquisition means for acquiring the current number of items currently registered in the database server from a registration count table which is managed for each database client; current registration count update means for updating a current registration count corresponding to the database client in the registration count table held by the database server; comparison means for comparing the maximum number of registered items with the sum of the current registration count of each database client; and control means for issuing a database processing request according to the comparison result of the comparison means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a database client, a database client program, a database client control method, and a database system, and can be applied to, for example, a database system that manages the upper limit of the number of data (records) registered in a database.

  Generally, in a database server / client system (hereinafter referred to as “DB-S / C system”), a database client (hereinafter referred to as “DB client”) to a database server (hereinafter referred to as “DB server”). A connection session is generated, a data registration request or an update request, that is, a transaction is transmitted, and a result is received.

  In the DB-S / C system, a DB client application (hereinafter also referred to as “APL”) needs to control transactions so as not to exceed the upper limit value of resources held by the DB server.

  For example, as shown in FIG. 4, in a conventional DB-S / C system composed of two DB clients and a DB server that holds a database, the maximum number of data (records) that can be registered in the database as a system is When the number is 1000, each DB client (DB client APL) needs to be controlled so that its own registration request does not exceed 1000 that is a threshold value (resource upper limit value).

  The maximum registration number (1000 cases) serving as a threshold is registered in a database (maximum registration number table) at the time of system construction, for example. Note that the maximum number of registrations usually does not change, and each DB client APL only refers to this data. Further, the current registration number (registration number table) in the system is updated by each DB client APL every time data registration processing is performed (+1 when data is registered, -1 when data is deleted). is there. Data registration (addition of records to the data table) is performed in conjunction with the update of the number of registrations.

  By the way, in the DB-S / C system, when a plurality (two in FIG. 4) of DB clients APL perform data registration at the same time, exclusive control is required to maintain data consistency (for example, Patent Document 1). For example, as shown in FIG. 4, a certain DB client APL performs data registration after locking the data in the registration number table and eliminating the transaction processing of other DB clients APL.

JP-A-11-272536

  However, this lock becomes a bottleneck in the DB client on the lock receiving side, and the registration processing performance of the DB client APL is suppressed.

  That is, the DB client on the lock receiving side waits for its own registration process until the number of registrations is unlocked. This means that the data registration processing of all DB clients concentrates and competes for data update of the number of registrations, and it is difficult to say that the DB-S / C system can exhibit sufficient performance. It was.

  Therefore, there is a demand for a database client, a database client program, a database client control method, and a database system that can execute processing on a database such as data registration without being affected by other database clients.

  In the first aspect of the present invention, in a database client that connects to a database server and makes a database processing request, (1) maximum registration number acquisition means for acquiring a maximum registration number that is the maximum number of data items that can be registered in the database server (2) current registration number acquisition means for acquiring a current registration number, which is the number of data currently registered in the database server, from a registration number table managed for each of a plurality of database clients; (3) Current registration number updating means for updating the current registration number corresponding to the database client in the registration number table held by the database server; (4) the maximum registration number acquired by the maximum registration number acquisition means; and the current registration Comparison means for comparing the total number of current registration numbers of each database client acquired by the number acquisition means; (5) according to the comparison result of the comparison means, and having a control unit for performing the database processing request.

  The database client program according to the second aspect of the present invention is a database client program for connecting to a database server and registering a computer mounted on the database client that makes a database processing request. Maximum registration number acquisition means for acquiring the number, and (2) current registration for acquiring the current registration number, which is the number of data currently registered in the database server, from a registration number table managed for each of the plurality of database clients Number acquisition means; (3) current registration number update means for updating the current registration number corresponding to the database client in the registration number table held by the database server; and (4) acquired by the maximum registration number acquisition means. The maximum registration count and each database acquired by the current registration count acquisition means. Comparing means for comparing the current number of registered sum of the client, characterized in that function as (5) in accordance with the comparison result of the comparing means, control means for performing the database processing request.

  According to a third aspect of the present invention, there is provided a database client control method used for a database client that makes a database processing request by connecting to a database server, and includes a maximum registration number acquisition unit, a current registration number acquisition unit, a current registration number update unit, And (1) the maximum registration number acquisition unit acquires a maximum registration number that is a maximum value of the number of data that can be registered in the database server, and (2) the current registration number acquisition unit includes: A current registration number which is the number of data currently registered in the database server is obtained from a registration number table managed for each of a plurality of database clients, and (3) the current registration number update means includes the database server Updating the number of current registrations corresponding to the database client in the registration number table held by (4) The maximum registration number acquired by the maximum registration number acquisition unit is compared with the total value of the current registration number of each database client acquired by the current registration number acquisition unit. (5) The control unit includes: The database processing request is made according to the comparison result.

  The fourth aspect of the present invention is a database system comprising a plurality of database clients and a database server that executes database processing in response to a database processing request from each of the database clients, and the database serving as a component of the database system The database client according to the first aspect of the present invention is applied as a client.

  According to the present invention, it is possible to execute processing for a database such as data registration without being influenced by other database clients.

It is a block diagram which shows the whole structure of the DB-S / C system of embodiment. It is explanatory drawing which shows the database table memorize | stored in the database of embodiment. It is a flowchart which shows the characteristic operation | movement of DB client APL of embodiment. It is a block diagram which shows the whole structure of the conventional DB-S / C system.

(A) Main Embodiment Hereinafter, an embodiment of a database client, a database client program, a database client control method, and a database system according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 1 is a block diagram showing the overall configuration of the DB-S / C system 1 of this embodiment.

  The DB-S / C system 1 includes two DB clients 10 (10-1, 10-2) and a DB server 20. The DB client 10 (10-1, 10-2) and the DB server 20 are connected to the network N, respectively. In the following description, the processing and configuration common to the DB clients will be described as the DB client 10.

  The DB-S / C system 1 is an environment in which a transaction such as database data update or registration is given from the DB client 10 to the DB server 20 and processing is performed.

  The DB client 10 gives a database transaction to the DB server 20. In FIG. 1, the number of DB clients 10 is two, but the number is not limited. The DB client 10 is installed by installing a client program on an information processing apparatus such as a personal computer (not limited to one, but may be configured to be able to perform a plurality of distributed processing), for example. Built. The DB client 10 includes a DB client APL 10A.

  The DB client APL 10A is an application that executes various types of processing (SQL processing, etc.) on a database. When registering or deleting data in the database 22, the DB client APL 10 </ b> A according to this embodiment performs processing on the database 22 after updating the number of registrations corresponding to its own client in a registration number table T <b> 2 described later. The detailed operation of the DB client APL 10A will be clarified in the operation section described later.

  The DB server 20 performs processing of a transaction given from the DB client 10 (DB client APL 10A), and has an RDBMS 21 and a database 22.

  The RDBMS 21 has a function of a relational database management system and, for example, processes a transaction received from the DB client 10.

  The database 22 is a data (record) storage unit. FIG. 2 is an explanatory diagram showing a database table stored in the database 22.

  The registration maximum number table T1 in FIG. 2A is a table that determines the maximum number of data that can be registered in the database 22 (a data table T3 described later). In the registration maximum number table T1, one piece of data is registered at the time of system construction. The DB client APL 10A can know the upper limit that can be registered in the database 22 by referring to this data.

  A registration number table T2 in FIG. 2B is a table showing the number of data currently registered in the database (data table T3) for each DB client 10. The registered number table T2 includes an item “DB client” for identifying each DB client 10 and an item “registered number” indicating the number of data currently registered by each DB client 10. The DB client APL 10A can know the number of data currently registered in the database 22 by referring to the “number of registrations” of the data corresponding to its own DB client 10.

  A data table T3 in FIG. 3C is a table in which predetermined data is registered or deleted by each DB client APL 10A. The items (items C1 to C3) in the data table T3 shown in FIG. 3C are examples, and the number of items is not limited to this. Further, in this example, for the sake of simplicity, an example in which one data table T3 is provided is shown, but it goes without saying that a plurality of data tables may be held. The maximum number in the registration maximum number table T1 indicates a threshold value that can be registered in the data table T3.

(A-2) Operation | movement of embodiment Next, operation | movement of DB-S / C system 1 of this embodiment which has the above structures is demonstrated. In the following, a description will be given by taking as an example the case where the DB client 10-1 registers data in the DB server 20 (database 22). Note that, when deleting data, basically, the same processing as that for registering data is performed, and therefore a description will be given as appropriate.

  FIG. 3 is a flowchart illustrating the characteristic operation of the DB client APL 10A according to the embodiment.

  The DB client APL 10A updates the “number of registrations” of data corresponding to the item “DB client” from the registration number table T2 (+1 at the time of data registration, −1 at the time of data deletion) (S101). For example, when the DB client APL 10A performs data registration processing, the value of the item “DB client” is “DB client 10-1”, and the value of the item “registration number” of the data is “401”. To “402”. At this stage, no data is actually registered in the maximum registration number table T1, and this update processing of the registration number is a reserved meaning for registering data from now on.

  Next, the DB client APL 10A acquires the number of data currently registered in the database 22 (S102). Specifically, the DB client APL 10A obtains the total value of the values of the “registration number” item of all the data in the registration number table T2. For example, the DB client APL 10A determines from the registration number table T2 that the “DB client” item is “DB client 10-1”, the value “402” (the value of the “registration number” item). In this process, “1” is added from the value shown in FIG. 2B) and the value “302” of the “registration number” item of the data “DB client 10-2” is acquired. Then, a total value (704) obtained by adding the number of registrations of each client is obtained.

  Next, the DB client APL 10A compares the maximum number of registrations, which is the maximum number of data that can be registered in the database 22, with the current number of registrations obtained by the process of step S102 described above (S103). The DB client APL 10A performs the process of the next step S104 when the current number of registrations is less than or equal to the maximum number of registrations, and performs the process of step S105 described later when the number of registrations exceeds the maximum number of registrations.

  The maximum registration number is a value input in the item of maximum registration number in the registration maximum number table T1, and is “1000” in FIG. For example, when the number of registrations obtained in step S102 is 704, the DB client APL 10A determines that the current number of registrations is equal to or less than the maximum number of registrations (1000), and executes the process of the next step S104. To do.

  The DB client APL 10A requests the DB server 20 to perform a process of actually registering (or deleting) data with respect to the maximum registration number table T1 (S104).

  If the DB client APL 10A determines that the current number of registrations exceeds the maximum number of registrations in the process of step S103, the DB client APL 10A determines that the registration error (registration number over) (S105).

  Then, the DB client APL 10A updates the “registration number” of data corresponding to the item “DB client” from the registration number table T2 (S106). Specifically, the DB client APL 10A subtracts “1” from the number of registrations obtained by adding “1” in the above-described step S101, and returns to the state before executing the process in the above-described step S101.

(A-3) Effect of Embodiment According to the first embodiment, each DB client APL 10A affects other clients if the number of registered data corresponding to its own client in the registered number table T2 is updated. You can register (or delete) data without receiving it. In other words, each DB client 10 can register (or delete) data without causing any waiting time by eliminating the need for exclusive control of data for managing the number of registrations commonly referred to by each client. It became.

(B) Other Embodiments In addition to the above-described embodiments, the following modified embodiments can be exemplified.

  (B-1) In the above embodiment, the maximum number of data that can be registered in the database 22 is provided as the maximum number of registrations as the entire DB-S / C system 1, but as a modification, each DB client is individually The maximum number of data that can be registered in each DB client is provided for each DB client, and the upper limit of data is managed by comparing the maximum number of registrations for each DB client and the current number of registered clients.

  (B-2) In the above embodiment, when the DB client APL 10A registers or deletes data, the DB client APL 10A obtains the current number of registrations and compares the maximum number of registrations (S102, S103). As a modification, when deleting data, this process may be omitted, and the process of step S104 may be performed after step S101.

  (B-3) In the above embodiment, the maximum registration number is managed in the form stored in the database 22 as the registration maximum number table T1, but as a modification, the DB server 20 is a file of a predetermined format. It is good also as a structure to manage (hold). In this case, the DB client 10 acquires the maximum registration number by accessing a file managed by the DB server 20. Further, each DB client 10 may be configured to acquire the maximum registration number in advance and store it in an internal file.

  DESCRIPTION OF SYMBOLS 1 ... DB-S / C system, 10 (10-1, 10-2) ... DB client, 10A (10A-1, 10A-2) ... DB client APL, 20 ... DB server, 21 ... RDBMS, 22 ... Database , T1... Registered maximum number table, T2. Registered number table, T3.

Claims (6)

In the database client that connects to the database server and makes a database processing request,
Maximum registration number acquisition means for acquiring a maximum registration number that is the maximum number of data items that can be registered in the database server;
Current registration number acquisition means for acquiring a current registration number, which is the number of data currently registered in the database server, from a registration number table managed for each of a plurality of database clients;
Current registration number updating means for updating the current registration number corresponding to the database client in the registration number table held by the database server;
Comparison means for comparing the maximum registration number acquired by the maximum registration number acquisition means with the total value of the current registration numbers of each database client acquired by the current registration number acquisition means;
A database client comprising: control means for making the database processing request according to a comparison result of the comparison means. The database processing request is a request for data registration processing for a predetermined data table,
The current registration number update means updates the current registration number corresponding to the database client in the registration number table according to the number of data to be registered,
The control means performs the database processing request when the comparison means determines that the total value is equal to or less than the maximum registration number, and when the total value exceeds the maximum registration number The database client according to claim 1, wherein the database processing request is canceled. The database processing request is a request for data deletion processing for a predetermined data table,
The current registration number update means updates the current registration number corresponding to the database client in the registration number table according to the number of data to be deleted,
The database client according to claim 1, wherein the control unit makes the database processing request regardless of a result of the comparison unit. Connect to the database server and connect the computer installed in the database client that makes database processing requests.
Maximum registration number acquisition means for acquiring a maximum registration number that is the maximum number of data items that can be registered in the database server;
Current registration number acquisition means for acquiring a current registration number, which is the number of data currently registered in the database server, from a registration number table managed for each of a plurality of database clients;
Current registration number updating means for updating the current registration number corresponding to the database client in the registration number table held by the database server;
Comparison means for comparing the maximum registration number acquired by the maximum registration number acquisition means with the total value of the current registration numbers of each database client acquired by the current registration number acquisition means;
A database client program that functions as a control unit that makes the database processing request in accordance with a comparison result of the comparison unit. In the database client control method used for database clients that connect to the database server and make database processing requests,
A maximum registration number acquisition means, a current registration number acquisition means, a current registration number update means, a comparison means, and a control means;
The maximum registration number acquisition means acquires a maximum registration number that is a maximum value of the number of data that can be registered in the database server,
The current registration number acquisition means acquires the current registration number, which is the number of data currently registered in the database server, from a registration number table managed for each of a plurality of database clients,
The current registration number update means updates the current registration number corresponding to the database client in the registration number table held by the database server,
The comparison unit compares the maximum registration number acquired by the maximum registration number acquisition unit with the total value of the current registration number of each database client acquired by the current registration number acquisition unit,
The database client control method, wherein the control means makes the database processing request according to a comparison result of the comparison means. In a database system comprising a plurality of database clients, and a database server that executes database processing according to database processing requests from each of the database clients,
A database system according to any one of claims 1 to 3, wherein the database client according to any one of claims 1 to 3 is applied as the database client that is a component of the database system.

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