This assignment has been takes place in order to understand the case scenario given and develop a required system as per your understanding. The coursework will enhance the database skills of the database designer and helps in future projects.
Database system is used to provide simple and convenient way to store, update and retrieve data from database. A database is a software program generated by computer which is used to access the data from database. Database not only cares about the data updating, modification and insertion in the database but it also cares about how to protect the data from unauthorised access.
What is Best Solution Database?
In ‘best solution database’ particular eachemployees will be known by their ID, Name and department name they are belong to. And in this database each and every employee can be work in one or more projects but they are not belonging to more than one department.
Every department have unique department code and they are identified by department code and department name. For different types of jobs or projects department code is also different. For example: Employees belongs to different department using different codes. Database stored details of each project and also stored which particular employee will be selected for each project.
Best solution database having important personal details of each employee and few points are given below why it is so important:
Itcan be described as available source of information which includes details of employees as Education information, contact information, work schedule, salary information and so on.
Best solution database are highly efficient. Members of the department can easily receive information about employees or management whenever required.
As the information is given by the employees should be correct or accurate and that information is straight from the source. Employee can be able to access their information at any time from database. Therefore, employee can keep database updated.
Update on time bound
The information added to the employee best solution database will be available for long time until those employees.
We are facing different kind of problems when we design the database, like data integrity, security, recovery and concurrency.
Data integrity is related to validity of data and it is basically used. It is use to maintain correctness and behavior of data which is stored in database, which is basically used to store, processes and recover data fromdatabase. There are several ways by which data integrity can be compromised. These are:
· Human errors when entering the data
· Viruses or software bugs
· Disk crashes or other hardware malfunctions
· Data transmission error from one computer to another computer
· Even natural disasters, such as floods and fire
There are some ways by which we can protect our database, these are:
· Controlling access to data via security mechanisms
· Design the user interface which prevent the database to invalid data input
· Regularly backing up the data
· By using the error detection and correction software when we transmitting the data
There are two rules related with data integrity in any database:
· Primary keys cannot have the value of NULL
· Foreign key can have a value of NULL
Data integrity can be fall under the conditions which is given below:
· Entity IntegrityEntity integrity requires that all the rows in a table have a primary key value or unique identifier.
· Domain IntegrityDomain Integrity applies an authorized entry for any given column within database system. It does this by the format, restricting the range of values and the type of entries which is being inserted.
· Referential IntegrityReferential integrity are the rows which cannot be deleted if a foreign key is pointing to the row because other records stored in the database is also used those rows.
· User-defined Integrityuser-defined integrity applies some sort of specific rule in the database system. It can be fall outside or inside of the other integrities.
By following the rules which are associated with data integrity we can maintain our database better and also find the information very easily. When an integrity violation is detected in the database, there are some methods which can be used to recover the data from damage. The methods are Majority vote, Raid parity, etc.
Majority vote-The majority vote strategy of recovering the data from damage helps to resolve the problem of determining whether the redundant information and actual data is stored is unmodified, in the case of a mismatch between both of them. The detection technique like mirroring is involved in the majority vote technique. When there is N copies of the data (N>2), upon the violation, the data contained in the majority of the copies can be unmodified, to some level of certainty can be recovered from the content in the majority of copies.
RAID Parity-RAID parity is uses an erasure code for generating the parity information at the bit level or block level. In computer, parity refers the technique of checking the data whether it is over written or lost when it is transmitting from one computer to another computer. The RAID parity is added a parity bit and binary bit with the group off bits that are moved together. The purpose of adding the bit is ensuring about the bits being moved are arrived successfully or not. The total number of bits is counted before it sent. At the receiving end each group of incoming bits is checked either it is odd or even. If the number is odd a transmission error is occurred and an error message is sent to the user.
In simple, Data security means protecting the data from unauthorized access by unknown user and protects it from corruption. The focal point behind the data security is to ensure the privacy while protecting the corporate and personal data. It also include the accidental or intentional demolition, corruption or infection of data. There is some steps which helps to protect the data, these are:
· Data encryption: Data encryption is a type of tool which helps us to protect or secure our data. In case, if the data is stolen or hard disk of the data is stolen then nobody can read the data if it is encrypted.
· Data backup: Data backup is also helps to protect and recover our data if it will be lose. But we have to ensure about the data is properly backed up or not, and also test it to confirm that when you need your data it will be recovered.
· Establish a strong password: we can also protect our data by implementing a strong password. It is an easiest thing and we can easily do it to strengthen our security. We can make a strong password by combining capital and lower-case letter, symbols, numbers and give it a proper length about 8 to 12 characters long. Make sure that every individual has their own user id and password.
· Strong firewall: A strong firewall protects our network by controlling the input and output internet traffic.
· Antivirus protection: Antivirus and anti-malware software are essential to our system. It protects our system from virus and malware which cause your data damage or corrupted.
· Database server security: we can secure our data by securing the server where the data is stored.
· Database table access control: The data stored in tabular form in the database.We can protect our data by giving a control on the database table.
Data recovery is the process of restoring or recovering the data in case, if it is losing, stolen, damage or corrupted. The data recovery software is used to recover the data and create the backup of stored data. We can also recover the lost data by creating the recovery point, date or time in the system.
Data concurrency is the terms or property of database system by which many users can access the data at the same time. But sometime in multiuser database there is some problems occur, so In general, the multiuser database uses some form of data locking which solve the problems occurs in data concurrency. Locks are the type of mechanism which prevents destructive interaction between transactions accessing the same resource. The resource includes mainly two types of object:
· The system object is not visible to users, like shared data structure in the data dictionary rows and memory.
· User objects such as rows and table.
We can also manage the data concurrency in following ways:
· Pessimistic concurrency control: In this method of managing the data concurrency, a table rows is available to the users.
· Optimistic concurrency control: In this method, a row of table will not be available to other database users while changing the data.
· Last in wins: In this method, row of table won’t be available to users while the data is in updated stage. The record is simply written out.
In case any employee can changes or update information he or she will able to update any information.
The information about the employees cannot be kept as public but it can also be kept as private from anyone except admin or the head of the organization. Therefore, it is safer to have an employee best solution database in an organization.
By taking these points above we can able to create the employee database system for Events R Us it includes all points as we discussed above about employees and database.
Several disadvantages of file system
· Data redundancy and inconsistency
· Atomicity problems
· Data isolation
· Concurrent access anomalies
· Security problems
· Difficulty in accessing the data
· Integrity problems
Advantages of proposed Database Systems (Event r Us)
· Controlling Data Redundancy- It enforce to make the data unique so that redundant data can’t be entered
· Elimination of Inconsistency – Since the repetitive data is entered, the changes made in one file will reflect the changes made in other file.
· Better service to the users- It provides timely and accurate information to the users which were not there in conventional file system.
· Flexibility of the System is improved- The data content changes can be easily done in centralized database as compared to traditional file system.
· Integrity can be improved
· Standards can be enforced
· Security can be improved
· Organization's requirement can be easily identified
· Data Model must be developed
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