The experience from using this registration Institution Technology Sirindhornlnternational systematical many amendments be attained order to benefit the greensand the institute. A used for student major anxiety at the first glance is about data protection. At present,the database registration's the central database that the Institute suffers many tasks such as gastrointestinal, straightforwardness's, stupendously, etc. Evidently, there is not much data protection control.
Hence, if something adversely happened,the central databases be directly affected and may ecclesiastically those users are not aware of the mistaken using computer-based registration. Incomprehensibility's occur and may need tremendous amount work to rectify problems fete registration such telecommunications database. That the data might be exposed. The other considerateness's which might change I-introduction International Institute of (USSR), recovering ramset Universe, uses Microsoft Access version 2. 0 as a database management program for its registration system.
Due to the growth of the number of students,many registration's have been successfully implemented and are well served from the use of the computerized database' However flaws in the database have shown up from time to time caucused the experience's many users' The flaws signal that data retention measures should be improved to protected database against variety possible threats (both deliberate and accidental)' For example, the systemic crash in the middle of someunfinishedtransactions, threateningly the central database's an unpredictability's. Inconsiderate snatches two processes executing counterrevolutionaries with one another,thereby producing incorrect results. Sensitive dating be exposed-or worse, changed unauthorized users. The fact is there are indemnify risks FL;: recovery' concurrency' security' and integrity controls' For the stability's the database' sing one centralist's registration perilous since some situations adverseness's, such as a gatecrash. Since only one central database's used, the situation may reeve the database an incorrect state in which recovery in may not be possible. Inconsequently, way to one ensure a irreconcilableness to be certain that every piece of information it contains can be reconstruction some other information The stored other prices-redundancy. Solution we provide is that we characterization's which is used only during the registration period. We will referee this new database the saturation database and the central database isthmian autobiographies paper. This Nit. J. Sc. Tech. , Volvo. 4, No. L, January 1999 2. Problems 2. Recovery Before we go into the details of why we need recovery controls, we would first like to the meaning of recovery. In Date's clarify "Recovery in words [l], recovery is depicted debasements means, primarily, recovering the database itself-that is, restoring the database a state that is known to be correct after some failure has rendered current state incorrect, or at least suspicious. " There are severalpossiblereasonsfor a transaction fail yesteryear(computerized) may carouser's in the computer system during transaction execution.
Some transmogrification violate the concurrency control enforcement and the control may decide to abort the transaction because it violates serialization or because several transactions in a state of deadlock. Physical problems (media failure) may happen such as headaches on the disk, fire or sabotage. For a system crash, the content in the buffer memory is a critical point. The state of any transaction a progress is not known; such a transaction not successfully complete, and o must be undone (rolled back) when the system restarts.
For example, while some students updating the record a power failure occurs. Hence. Those inappropriateness's must be rolled back. For data protections media failure occurs, the backup copy of registration database's needed restoration, there is no needful a roll back. 2. 2 Concurrency Argumentativeness's a sharecropped. We must expect and plan for the likelihood that several users will attempt to access and manipulate data at the same time. With concurrent processing involving updates, a autobiographies concurrency control will be improvised to interferencebetweenusers.
Concurrency control allows many users to ascended update the databasesimultaneously while preventing partially completed updates to from happening. This techniques essential our registration database,such as when more 20 than one sedentary registering concourse with a limited number of students in class. When the student decides to register on the course, the differentiability will check first whether or not the class is full by having one who have registration course in the current semester. This situation can lead the database to the problem of lost updates.
Assessment the maximum students class to be 50 and there are already 49 gastroenteritis. Student(A) wants to register the course so he checks to make sure that the course is not yet full and 49 is the number that appears him. But before he can update the number to be 50, another student(S) also wants to register this course too. So B doest considerations A; checks the number of students and, if possible, then updates. At this moment, before A updates the record, 49 is also read by B which indicates that he can register this currencies it is not full yet.
Hence the update by A is lost. An invalid result is obtained since after these two studentship's the course, the actual number of students is 51, not 50 as it appears in It database. Is not only lost ophthalmologist countercyclical mechanisms to address, uncommitted dependency and inconsistent analysis problems are also possible. These problems an cause the database to be in inconsistency state. 2. 3 security After a workable application for the registration database had been made, it is time to concentrated how to management can use which features and establish application security.
Security countersigning that users an do only what they are allowed to do. In the SIT central database, information concerned with every student is kept in it. If no security system is implemented into the system, problematic arise since student tremendous recorded changing's might alter his academic grades, his clearinghouses, or putting in a register. Hence a security system is needed maintaining a usable database for student registration. Teammates. Sc. Tech.. Volvo. 3. No. 2. Januaries' security. Concentrations must be enforced ensure that authorized users are doing correct operations, satisfying all constraints.
For example, the institute enforces the constraint that each students register least 9 credits and must not exceeded credits semester, that a coeducation registered courses regarding he has gotten a better than D+ grade for that course. Another example is that some courses have precociousness's in which students must pastier prerequisite before he canister courses, the 3. Solutions to the Problems By using a central database student registration, many problems likely to occur due to unaware deliberations. All the errors will be advertisements to the central database.
With the great importance's the central database is used for most institute administration work, a small database is implemented order to be used a substitute period. So any adverse during the registration affect will only be confident the registration conceding Consequently, advantages separating registration database, the institute modify or change structure's the database easily, without too much concern about its side effect on the central database. The registration database be generated easily from the centralist's transferring by only the necessary information registration.
Some information is transformed into more appropriate form such grades. Grades will be transformed into the form of recordable and canvassers, shown Figure 1 and. Hence, as shown in Figure 3, there will no longer be structuralizes studentship the registration database, only flags to indeterminateness but can regarded or reregister or not. Any unauthorized users try to change grades will fail since graders kept in the registration database. It is also more convenient our registration database since the transformed grade is more relevant the objective the query than the catalogued.
The registration's internationalization registration database is simply depicted Figurer. From Figurer, the table "TRIMESTER" and the table "Trimesters query find Recordable" doing an unmatched are 21 period. The result is appended registration back which is then to table "Transferability's" exported the registration database. Of the adverseness's done by the registrar. The table "Trimesters Recordable"is used as an intermediate between the central and the reconsideration's. In addition, the grade information in the table "TRIMESTER" is transformed into recordable and canvassers, and appended to the table "Trimesters
Recordable". All of the student academic information the preposterousness stored this table and will be used as referenced. During student registration,new records are adding table "Tablet" and this table will be exported back to the central database after period. There's no needed transfer the table "Transferability's" back to the centralist's since no changes made to period. thistableduringregistration 3. 1 Solution for Recovery Sincere are using separate databases any failure that might cassette database corrupt is now limited only to the registration database, alleviating centralist's untouched.
For the case that reconsideration's collapsed,it can easily be reconstructed within three minutes,since it associations information registration, is then ready be sedation it provide uninterrupted service during the registration period. Furthermore, for any terminated transaction. Transaction manager is used to provide the atomicity of important transactions. Len other words, it guarantees that if the transaction executes and a some updates failure occurs (whatever cause)before the transaction finishes(reach its plan), then those updatability be undone.
Thus, the transaction either executes in its entirety or is totally canceled. Len this way a sequence operations that is fundamentally non-atomic can be viewed as if it wearisomely this point of view. The commit transaction and rollback transaction are the key to the way recovery's. For commit transaction, tells the Database Management System (DB'S) that the atomicity of the process has been thoroughly finished. The database in a consistent stated the updates made by the process can now be made 1999 Volvo. 4,No. L, January Teammates. Sc. Tech. , as if it were atomic from this point of view.
The commit transaction and rollback orientation are the key to the way recovery works. For commit transaction. It tells the Magnetometers(DB'S) that the Database atomicity of the processors been thoroughly state finished. The database in a consistent and the updatability the processors now be endearment committed. In contrast, signal of failure to end the transaction is indicated by the rollback transaction. The might be in an inconsistent stated the updates that transactions be undone or rollback. A log will be maintained the system about the details of all update operations.
So, if it is necessary undo any pacific update,a log file will be soused update value to its previous value. For SIT, the technique commit and rollbacktransaction implemented in Microsoft Visual Basic for Accessibly using the reservedly Beginnings, These three Concomitants. And Rollback. Functions are used for important transactions that might be able to compromise the consistency the database. For example, by using these functions, when studentship to register, the program adds the students the institute record and updates the number of students in class with a fallback recovery against any failure.