Introduction to Database Management System
Database management system is an application used to connect with user. It is also used to interact with various other applications in data evaluation.. Database is an important and intrinsic part for any organisation system. It is tool use by companies to store their data of employees. information of their work and various other kind of data. Database are use to store and extract data. DBMS is an application which is provides organisations a platform on which all the information is managed. It allows user to access data, update data and searching of data. It gives many links to user like programming, analysis of systems, human computer interaction and interfacing with systems.
Present report describes about various issues and problems in database application in context with organisations environment. Evaluation of feature and database of DBMS system in companies has been done. Further more, development methodology of database in enterprises have been evaluated. Entity relation ship model for the given organisation has been illustrated. More over, database development cycle and, concept of normalisation has been explained. Effectivenesses of DBMS and improvements required are also illustrated.
1.1 Key issues and application of databases in organisations
There are various issues discovered in database of Shoengalleric Art Gallery. Database have many issue which can effect the proper functioning of the organisation (Abadi and et.al., 2013). Issue like redundancy of data, interdependency, security issue, data integrity and data validity. Following are some issues of company's database :
Data Redundancy: It is the most vital issue which is found in database of the organisation. Data redundancy is the condition in which same data is reflected in two different places (Coronel and Morris, 2016). This means two distinct places are showing same information which is causes repetition problem. Redundancy occurs when two or more tables in the database holds same value. For example in art gallery shop redundancy can occur when two customers have same name.
Security Issue : Security of data is termed data stored in database should be kept safe from unauthorised people. as Security issue occurs when organisations stores the information of customers, financial data, HR records etc. Large amount of information contained in database can be steal by hacker for illegal use. The theft of information can causes loss of reputation of firm. Is also causes problems to customers.
Data integrity : It is defined as consistency and accuracy of data. It is indicated by alternation of data within two tables of database. In designing phase of database it is needed that data is stored ion right table and no repetition/ missing of data is there.
Data validity : It is defined as validation of data in the single database. It is a process used to ensure that all the field within the database are showing some valid value. Consistent value is required in the table and table should not return null value (Di and Kerns, 2015). For example in customer database of shop amount field of table can not contain null value.
Application database in organisations
Databases in organisation plays an important role in storing data of company. An organisation contains three level of functional activities. The data of all these activities within the organisation is stored in the database. Corporate database holds data related to company, operations and various plans. It provides effective storage of data. It allows users to put queries and access of data. It provides a platform in which is user friendly and provides easy interaction to users. There are various roles of database administrator which are taking back ups, recovery of data, creation of new database, ensuring security of database and upgrading database.
1.2 Feature and advantage of database management system
There are various features of database management system that can help Shoengalleric Art Gallery shop in managing the data. DBMS applications are used widely by all business entities to mange the data effectively. Some benefits of database management system in the organisation are as follows:
Data availability : it is one of most useful feature of DBMS which helps in reflecting same data of firm available to many employees at the same time. It supports in enabling multiple access to authorized users (Dimitrieski and et.al., 2015). That data is made available to all the users remotely. For example gallery shop can made its data available every time to all its branches. Its employees can access data at any time using internet.
Minimized redundancy : Data and information stored in which is stored in database management system is compact and it appears only at one place. This feature help in reducing redundancy of data. For any business for it required that data should repeat again and again. DBMS help in reducing the cost of maintaining significant information of business in storage devices.
Accuracy and consistency of data : DBMS provides accuracy of data by using data integrity feature (Embley and Thalheim, 2014.). It gives user a relevant piece of data for use. Using database organisations can assist the integrity of their significant records of business. It provides a platform on which changes are to be made only at one place. It also prevent faults,bugs, and loss of data.
Features of DBMS:
Consistency : Implementation of database any organisation benefits them to sue file formats that are consistent and standard. This feature make the data manipulation and update easy. It became easy for business venture to easily update data because there are some rules in database which are applied to al type of data (Coronel and Morris, 2016). Customization of business records become easier due to this feature.
Data structuring : Whole data in the database is stored in the form of hierarchical structures. Table, rows field and tuple are used to feed data. It become easier for administrator to update and recover the data.
Query languages : DBMS uses query languages to store and retrieve data. Query language are use for data collection, searching , data sorting, modification and manipulation
Customized database : DBMS provide various options that can be used to make customized elements according to requirement of user.
Metadata : Data base management system provides a library which is called metadata. This data dictionary gives information about how data is organized within the system.
2.1 Data base development methodology
According to case study Shoengalleric is an art gallery which is situated in China. Company has many branches sin the country due to which it is difficult for the gallery to mange its data using paperwork methodology (Embley and Thalheim, 2014). Sharing of information is poor due to use of old method in storing data. The organisation wants to build its database for effective management of data. Data base will help gallery in reducing errors in storing of data. Following are the designing methodology that should be used in making of database for the art gallery. The methodology is divided into three parts :
Conceptual database design
In this designing method conceptual data model is made for the organisation. This model is totally depends on implementing details like target DBMS,system programs, languages for programming and issue of performance (Harrington, 2016).
Logical database design
in this database design construction information does not depends on particular database management system. This type of designing method uses conceptual model to make logical model. This model gets affected by data models like relational database model. This logical model works as a source of data for physical model (Hernandez, 2013). It generates output in form of global logical model which contains ER diagram and relational diagrams. Data dictionary is also the part of this model. All this information is used by physical designer to make efficient design of physical model.
Physical database structure
In this method database is implemented on secondary storage devices. This phase explains about base relation, organisation of files and various indexes used for accomplishing data access. This type of database design allows database designer to determine how to implement it.
There are various components used in database deigning methods which are as follows :
Requirement specification : In requirement analysis phase two aspect are considered. First is planning in which system strategy is considered. It also concerns about planning of whole DDLC. Second one is system definition in which scope and limitation of the present database is defined (Kiani and Zivari, 2014).
Database designing : In this two model are given consideration to create database. First is logical model in which complete design of database is made on paper. Second is physical model in which logical model is use to make decision of this phase.
Implementation phase : In the implementation phase conversion of data and testing of system is done.
2.2 Entity relation ship modelling and normalization techniques of database
There are two techniques which can be used by Shoengalleric art gallery to design it database. Techniques are as follows:
ER modelling : Entity relationship modelling is used in designing of database. This model uses object of real work to represent relation between entities. (Shu and Cheong, 2014) Entity is defined as an object which is different from on another. Example of entity in case can be employee of art gallery organisation. Entity can contain values. ER model is an technique use to understand and manage data which is independent form the real database.
ER modelling have following components :
- Entity : It is a thing which has independent identity. This is the base on which data is collected. For example employee of firm is an entity.
- Instance entity : It is a particular subset of entity type such as particular employee of employee entity type.
- Regular entity : This entity contain its own characteristic such as particular employee will have it unique attributes (Vissers and et.al., 2016).
- Weak entity : This entity depends on another entity for it attributes. This type of entity does not contain any key characteristic. For example leader and employee relationship in which employee depends on leader for everything. Here employee is weak entity.
- Attributes : Attributes describes properties and detail of entity. These attributes ion er modelling are described using oval shape (Embley and Thalheim, 2014). For example employee attribute will be name , phone no. , address etc.
- Key attribute : It is an attribute which remains unique for each entity in the model. Such as employee_id, employee_name, employee_address etc. Any key attribute which contains two or more characteristic the it is called composite key.
- Simple attribute : It is a single attribute which have no further scope to be divided. For example id of employee emp_id (Dimitrieski and et.al., 2015.).
- Composite attribute : It is an attribute which can be divide further. Such as emp_name , emp_first name, emp_last name.
Line which connects entities together are called relationships. For example workers works for art gallery. Here “work for” is relationship between worker entity and firm . Notation for relationship in ER modelling is diamond shape. Weak entities are connected by weak relationship notation which is diamond within diamond. Relationship degrees are unary binary and ternary (Hernandez, 2013). Cardinality of relationship is 1: 1, 1:N, M:1, M:M.
Normalisation in database
Normalisation is process in which anomalies in the database are removed for making consistent database. Anomalies like repeated data, data duplicacy and wrong manipulation of data are removed to ensure consistency (Vissers and et.al., 2016). In this process three step are followed which are update anomalies, delete anomalies and insert anomalies.
Normalisation has 3 normal forms which are as follows :
First normal form : 1NF is defined in the table definition itself. This describes that all attribute within the relation should have atomic field. Value in atomic field are indivisible.
Second normal form : 2NF contains prime and non prime attribute. Prime attribute is part of prime key and non prime is not the part of prime key (Shu and Cheong, 2014).
For example non prime has functional dependency on prime key. If A-> B contains then there cannot be any subset of C of A in which C-> B is also true.
Third normal form: A relation should in 2NF to be in 3NF. In this normal form non prime attributes depends transitively on prime key.
Boy codded normal form : BCNF is an extension of 3NF. It describes that no trivial functional dependency A-> B A should be a super key.
According to the case study it has been found that Shoengalleric art gallery organisation was facing issue in marinating its data as paperwork in the firm was increasing due to use of outdated procedures used in the office. This issue can be solved by using database design techniques. Organisation is facing data repetition problem in old method of data storing. These database will support company to achieve minimized redundancy of data. Database administrator of the firm will be able to made data available to all the workers of the organisation. The data availability feature of the database system will help company to give access of data to all the authorized workers.
Data consistency is also an issue in the storage of data. Data consistency feature will help organisation in providing accurate data to its users. Employees of the company can easily search data in database, update and manipulate data. This would be easy for workers of art gallery by using query languages. Data dictionary will help users to understand the structuring and operations of database. Making customised database would also be easy for organisation.
Database development methodology will support database designer to design it make efficient database. Appropriate requirement analysis will support designer to make effective database which can solve current issues of company. Planning phase of requirement specification can help in finding appropriate strategy. Using logical model and physical model approaches will make it easy for designer. Testing is required of database to identify errors and bugs in the proposed system. Entity relationship modelling can help in making entities in making entities in organisation's database. Designer can use employee and customer entities to define relationships. All the attribute of employee entity can support in making effective database of employees. This database would contain information about each employee in each store of the gallery. Attribute of customers would get saved in customers database. This database would contain all the data about each customer of art gallery.
Database system can also solve the issue of record keeping of product. Manager can easily maintain the data about products. Data bas administrator of the organisation can update, delete and manipulate the data about products. DBA can insert the data about product if it is available in the store. Similarly deletion would be done on unavailability of item. DBA can use normalisation process to remove anomalies in the database. Removing errors would be easy for company by using normalisation method which was not available in older methods.
Proposed database management system has been made by database designer which has solved various issues of company. Issue of data redundancy has been solved by using database to store data. Shoengalleric art gallery manager is now able to make data available for its employees and user. Authorized user can access the data remotely anytime. It has helped organisation to make data consistency in database. Security feature of system has been supporting company to secure their employee and customer data. Thus data security has been enhanced in the organisation. ER diagrams has supported in making appropriate entity for each data which is to be store in the application. Normalisation technique has been used in database to remove errors and bugs form the system.
Database development life cycle has supported in require collection analysis, data conversion and testing of data. DDLC is also helping maintenance and prototyping of data. However, there are some problems in the current database system as some value in the table field are repeating. On adding age data of employee in the field the system is returning null value. Customers information is redundant in the database. Same information about one customer reflects in two field which is causing data redundancy issue. There is some security issue also which is allowing unauthorized user to access data of customer. In the newly designed database there are some errors which is causing problems in deleting the obsolete data form the database. Data validity problem is also there in the database due to which some field are returning null values.
Summing up the above report it can be concluded that database is necessary requirement for any organisation to store and retrieve data effectively. It helps in organising and managing significant data of the company. Database features like data redundancy, data consistency, data integrity and data validity supports in making effective application system. Various issue in maintaining data using old approaches gets solved. Database development methodology is an effective tool used in designing of database. Logical, physical and conceptual model are used in this methodology to design database system of the art gallery. DDLC approach is an effective approach to design database. Normalisation is a feature of database that removes anomalies form the database. Entity relationship diagram define entity and relationship between those entities.
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