JPS592159A - Data controlling system - Google Patents

Abstract

PURPOSE:To reduce frequency generated by an undesired waiting state, by executing a registration onto a control table as necessary by a user, and inhibiting an access from other user against the registered access unit. CONSTITUTION:When a user checks one record in some access unit, and thereafter, executes write to a record in other access unit, in case when he desires an exclusive control to the latter record, an entry regarding the latter record is added onto a control table 3 by an inserting command. When the entry concerned is registered, a data base control system 2 operates to a record corresponding to the registered entry as if the access is executed in a locked state, and inhibits updating from other user, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (4) Technical Field of the Invention The present invention provides a data control method, in particular, a data control system, in which the control unit of exclusive control performed by a database management system is kept relatively small, and then The desired control unit is controlled so that it can be temporarily locked,
This invention relates to nine data control methods that suppress the frequency of occurrence of undesired waiting states as much as possible.

(6) Technical background and problems In databases, an access unit consisting of one or more records is treated as the minimum access unit, and users are organized into a logical structure under the control of a program called a database management system DBMS. It is configured so that records can be accessed using . Then, when trying to update a record consisting of
The database management system performs exclusive control based on the access unit. In other words, when multiple users are attempting to update the record at the same time, only one user is allowed to perform the process, and the others are not allowed to perform the process. will be forced to wait until the end.

If such a unit of exclusive control is set to a large size, while one user is updating a record, another user may try to update a different record within the unit of exclusive control. In some cases, you may have to wait,
The larger the unit of exclusive control is, the more serious one problem becomes.

For this.

However, the unit of exclusive control mentioned above will be made smaller.

For example, when a user performs processing conversationally,
There may be cases where you want to check the contents of a record in an access unit, write to a record in another access unit, and then prevent other users from updating the contents of the latter record. .

In such a case, it is not preferable to increase the unit of exclusive control, and it is desirable that the user be able to place a desired record in a locked state by temporarily registering it.

The present invention aims to solve the above problems.
The data control method of the present invention includes a database in which a plurality of access units each consisting of one or more records are stored, and the access unit is controlled in response to control from a plurality of application programs. In a data processing system equipped with a database management system that performs exclusive control of Based on the state in which the lock request and/or lock release request is registered on the control table by the command.

The database management system is characterized in that the database management system prohibits updates to the registered records. This will be explained below with reference to the drawings.

0 Embodiment of the Invention FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flowchart of an embodiment illustrating access to a control table according to the present invention, and FIG. shows an explanatory diagram illustrating the correspondence between commands and the contents of the control table.

In FIG. 1, l is a database, 2 is a database management system (DBMS), and 3 is a control table, which can be provided in the form of il) in the present invention.
4-0.4-1. . . . are application programs, 5-. 0.5-1. -i respectively the user (or the terminal used by the user), 6 represents the command (or the data format of the command) used in the present invention. Also, songs A, B, etc. represent the entire areas of files A and B, respectively, and 7 represents the access unit, which in the illustrated case is also the unit of exclusive control performed by the database management system.

It may be considered that the database management system 2 has an original function of, for example, a function of prohibiting other users from accessing an access unit while an update process is being performed by the user who constitutes the access unit.
In the case of the present invention, this function is utilized. In the case of the present invention.

Command 6 is prepared so that the user can register it on the control table 3 as necessary, and when viewed from the database management system 2, the registered access unit can be seen as if it were actually being updated. Furthermore, access from other users to the registered access unit is prohibited. Note that the key on the control table 3 is a key for identifying records, and L
D is a key that can identify the user, and "data" represents the actual contents of the record.

As for the operation code OP of command 6.

(I) R+r#αd (reading) Read the entries on the control table 3.

(1) is 1FzJ1ert (addition)...
...Add an entry on control table 3.

(110u: updαta (change)...
The contents of the entries on the control table 3 are changed.

It can be assumed that there are such things.

When a user checks one record in an access unit and then writes to a record in another access unit, if he desires exclusive control over the latter record, the user selects state S1 shown in FIG. An entry related to the latter record is added to the control table 3 using an insert command as shown in FIG.

Note that when the entry is registered by the addition, the database management system 2 operates as if the record corresponding to the registered entry is being accessed in a locked state, preventing other users from accessing it. Updates etc. will be prohibited.

When adding in the above state S1, the control table s
Assuming that the record is not registered above,
The process advances from state S2 to state S6, and locking is completed. If it has already been registered on the control table 3, the above addition will result in an error. At this time, since the lock for the access unit may have been released (unlocked) depending on the case, state S shown in FIG.
Try executing the update command as shown in step 3. Note that disguising the iD as PlankLo in the update φ command can be considered to mean that if the iD on the control table 3 is blank, it should be changed.

After issuing an update command, a read command (not shown in FIG. 9) is issued to read whether or not the entry on the control table 3 has been changed. If the change was successful, proceed from state S4 to state 86,
The lock is completed.

If it has not been changed, state S shown in 9
It becomes busy as shown in 5.

Entries registered on the control table 3 are unregistered by a command when necessary processing is completed. In this case, as in the illustrated state S7,
An update command is used, and the iD in the data section of the command is set to Plankro. This means that the iD of the entry on the control table is changed to blank.

This will be explained in detail with reference to FIG.

Now, suppose that the control table 3 (3
-A), the entry corresponding to the record with (1) key Kl remains unlocked, and (1)
The entry corresponding to the record with 2 in the key is user I.
8, and the entry corresponding to the record with 3 in the +10 key remains unlocked.

Under this state, as shown in FIG. 3(B), user I6 inserts a record with key 4 to lock it.
Suppose you issue a command. At this time, if the command is accepted, an entry corresponding to the record having 4 in the key is registered as shown in Table 3-B.

Under this condition, for the record number 2 with 1 in the key, the third
Assume that the user 110 issues an insert command as shown in FIG. In this case, the entry for the record with the key Kl remains unlocked in the control table 3.
(3-B) An error occurs because it remains on the top. And when user IIO issues an update command,
When the update is accepted, tD is set to IIO as shown in Table 3-C.

Next, it is assumed that the user I12 issues an insert command as shown in FIG. 30 for a record having a key of 1. In this case, the entry for the record with key 1 remains locked and is sent to control table 3 (3-C).
An error occurs because it exists above. Then, even when the user IIO issues an update command, the change is not accepted and results as shown in Table 3-D.

Note that under the condition shown in FIG.
for records with 4 in the key.

When you issue an update command such as the command <(14, ni 4.l6) (K4tu, D)> and perform the unlock process, entries will appear in table 3 in the form rK4゜, D J. The rest will be unlocked.

■As described in detail, according to the present invention, the unit of exclusive control is set small, and a database is controlled in a manner as if a record consisting of the above is being accessed by a user or a command. It becomes possible to make a reservation by showing it to the management system. This reduces the frequency of undesired waiting states and makes it possible to make necessary reservations.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating access to a control table according to the present invention, and FIG. 3 is a diagram showing commands and contents of the control table. An explanatory diagram illustrating the relationship between the two is shown. In the figure, 1 is a database, 2 is a database management system, 3 is a control table, 4 is an application program, 5 is a user, and 6 is a command. Sai1m Sai11 '1'3 flash

Claims (1)

[Scope of Claims] A database is provided in which a plurality of access units constituted by one or more records are stored, and exclusive control of the access units is provided in response to control from a plurality of application programs. In a data processing system comprising a database management system that performs The record is configured to be registered on a control table as a pair of a key that identifies the record, an ID that can identify the user, and the record contents, and the user registers a lock request and/or a lock release request on the control table by a command. The data self-control system is characterized in that the database management system prohibits updating of the registered record based on the state of the registered record.