Benefits Of The Entity Relationship Diagram

Published Date: 02 Nov 2017

Basic idea of data model is a plan for building a database. Describing how can we use data and representing data are purposes of the data model.

Different data models

Physical data model

A physical data model represents the actual structure of a database tables and columns or the messages sent between computer processes. Here the messages sent between computer processes. Here the entity type usually represent tables and relationship type lines represent the foreign keys between tables

Logical data model

Logical data model all entity types have attributes and relationship types for all the data. That is called as "fully attributed". Also that model fully normalized. Logical data model might relate to a physical model but that is not the only possibility.

Conceptual data model

Conceptual data model is a model of the things in the business and the relationship among them, rather than a model of data about those things. A conceptual data model might include some rules, but it would not place limits on the data that can be held about something or include derived data,

Canonical data model

This means a data model that is fully normalized and in which no derived data is hels. Because of that logical data model might or night not be a canonical data model.

Intergration data model

Intergaration data model intergarated with a number of separate applications. In order to do this it need to instantiable.

why older data models are being replaced by new data models ?

The technologies are not really all that new It’s just that "traditionally" data modelling has not been seen as being relevant to these areas. we need to show how and why data modelling IS relevant for today’s varied IT landscape. Thus we must show that it’s relevant for the new technologies. Because of that we shold repalce the older data models being replace by new data models.

Task 1.2

Briefly explain the benefits and limitations of having the entity relationship diagram and explain the database normalization.

Entity Relationship diagram (ERD)

ERD stands for Entity Relationship Diagram and it is basically a snapshot or brief of various data structures. ERD is developed to show the entities present in a database as well as the relationship between tables in that database

Benefits of the entity relationship diagram.

provides a visual representation of the design.

It is normally key to have an ERD if we are looking to come up with an valuable database design. This is as the behavior allow the designer in focusing on the method of the database will primarily work with all the data flows and relationships. It is general to the ERD being used collectively with data flow diagrams so as to make a better visual representation

makes effective communication.

An ERD actually conveys the key entities in a some database and their relationship with each other. ERD usually provides symbols for representing three different kinds of information. Diamonds are used for representing the relationships, ovals are usually used for representing attributes and boxes represent the entities. This allows a designer to effectively communicate what exactly the database may be like

simple to understand.

ERD is simple to understand and simple to create. In impact, this design can be used to be offered to the representatives for both authorization and evidence. The representatives can also make their contributions to the design, giving the ways of rectifying and developing the design

High flexible

The ERD model is so flexible to use as additional relationships can be derived instantly from the currently available ones. This can be done using other relational tables and mathematical formulae.

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The ERD therefore the ERD acts like the plan for the database and it make it possible for the creation of an accurate design that demonstrates the needs of the project.

Limitations of the entity relationship diagram.

Limited constraint representation.

Limited relationship representation.

No representation of data manipulation.

Loss of information.

Database Normalization.

Normalization is the process of creating table designs by assigning specific field or attributes to each table in the database. A table design specific the field and identifies the primary key in a particular table or file. There are two goals of the normalization process.

eliminating redundant data

Ensuring data dependencies make sense.

Both of these are worthy goals as they reduce the amount of space a database consumes and ensure that data is logically stored.

(shelly, et al., 2009)

The Normal Forms

The database has developed guidelines for determining that databases are normalized. These are referred to as normal forms and are numbered from one to five. In practical applications, we often see 1NF, 2NF, and 3NF along with the occasional 4NF. Fifth normal form is very rarely seen.

1st normal form.

First normal form (1NF) sets the very fundamental guidelines for an established database.

Preventing duplicative columns from the same table.

Create different tables for each group of related data and identify each row with a unique column or set of columns.

2nd normal form.

Second normal form further cover the concept of removing duplicative data.

Encounter all of the requirements of the first normal form.

Remove subsets of data that apply to multiple rows of a table and place them in different tables.

Bring relationships between these new tables and their predecessors through the use of foreign keys.

3rd normal form.

Third normal form goes further one step.

Encounter all the requirements of the second normal form.

Remove columns that are not dependent on the primary key

Boyce Code normal form (4th normal form)

The Boyce-Code Normal Form, refers one more requirement.

Encounter all the requirements of the third normal form.

Every determinant should be a candidate key.

(Chapple, n.d.)

Task 1.3

Briefly explain the concept of database management system and its importance using examples from the different database environment.

What is database?

A database is a collection of information that is established so that it can instantly be accessed, managed, and updated. In one vision, databases can be classified according to types of content.

(Leake, 2006)

What is database management system (DBMS)?

A DBMS is greatest referred to as a collection of programs that handle the database structure and that control shared connection to the data in the database. Latest database management systems also store the relationships between the database components and take care of determining the required access paths to those components.

A database management system is the combination of data, hardware, software and users to help an enterprise manage its operational data

(Anon., n.d.)

Importance of DBMS.

In Business.

A database management system (DBMS) is the category of applications used for creating, organizing, retrieving, analyzing, and sorting information.

Businesses have many uses for accurate, complete databases. Firms usually maintain databases of clients, vendors, employees, inventory, supplies, product transactions, and service requests, among additional things. A database system that can manage all the acceptable attributes of a type of data and to provide the ideal methods for analyzing the data is key management tool for all businesses

In banking and finance.

If database systems are release it will take long time to process all the financial dealings manually and the stock exchange also relies on computer systems for recording purchase and also selling of stock that happens very instantly and also in large quantities. The sum of money involved in these transactions in large.

In transport.

The airlines all use online seat reservation systems and have system for scheduling aircraft, for building and maintaining timetables, for handling the in-flight catering and for mechanical servicing of the planes. Similar systems exist for railway, sea and road transport, they all use database technology.

In education.

Courses, materials and assignment all expect highly on database technology in all sectors of education. All too the between of database technology with hypermedia delivery systems make it possible for courseware to be maintained up-to data and release to the consumer.

In healthcare

Primary healthcare has long expected on database technology to arrange hospital beds or appointments at clinics. The patient health report has been the subject of intensive study over many years as of its complexity of structure, content and media and also because of the confidence and privacy issues. Epidemiology uses database technology to keep and organize key information from many patients in order to allow statically reproduction to identify trends and to alert medical practitioners to possible epidemics. More currently data mining technology have been applied to this area dependent again on database technology

In government sector.

Government administration will be paralyzed without database technology. The collection of taxes and payment of social security features depends totally on database technology

( Kedar, 2009)